One of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing October 8, 2022JPEGOctober 3, 2023JPEGOctober 8, 2022October 3, 2023October 8, 2022JPEGOctober 3, 2023JPEGOctober 3, 2023JPEGJuly through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought.The OLI (Operational Land Imager) instrument on Landsat 8 captured this image (right) of the parched Rio Negro in the Brazilian province of Amazonas near the city of Manaus on October 3, 2023. On that date, the level of the river, the largest tributary of the Amazon River, had dropped to 15.14 meters (50.52 feet), according to data collected by the Port of Manaus. For comparison, the image on the left shows the same area on October 8, 2022, when the water level was 19.59 meters, a more typical level for October. Rio Negro water levels continued to drop in the days after the image was collected, reaching a record low of 13.49 meters on October 17, 2023.Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia.“Overall, this is a pretty unusual and extreme situation,” said René Garreaud, an atmospheric scientist at the University of Chile. “The primary culprit exacerbating the drought appears to be El Niño.” This cyclical warming of surface waters in the central-eastern Pacific functions somewhat like a boulder in the middle of a stream, disrupting atmospheric circulation patterns in ways that lead to wetter conditions over the equatorial Pacific and drier conditions over the Amazon Basin.According to news outlets, the low river water levels on the Rio Negro and other nearby rivers have disrupted drinking water supplies in hundreds of communities, slowed commercial navigation, and led to fish and dolphin die-offs.Manaus, the capital and largest city of the Brazilian state of Amazonas, is the primary transportation hub for the upper Amazon, serving as an important transit point for soap, beef, and animal hides. Other industries with a presence in the city of two million people include chemical, ship, and electrical equipment manufacturing.NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe water level of the largest tributary of the Amazon River has hit a record low.Image of the Day for October 18, 2023 Image of the Day Water Human Presence View more Images of the Day:The impact of severe drought on the Negro River, a tributary of the Amazon River, and other rivers in the basin is dramatically evident in this pair of images, which show that every body of water has shrunk in 2010 compared to 2008. Image of the Day Atmosphere Land The volume of water in New Mexico’s largest reservoir has dropped to historic lows due to drought and persistent demand. Image of the Day Water Human Presence Acquired June 25, 2011, and June 22, 2010, these false-color images compare conditions along the Souris River, which reached a historic crest at Minot, North Dakota in June 2011. Land Floods Acquired May 11, 2011, and April 21, 2007, these false-color images show the Mississippi River near Natchez, Mississippi. The image from May 2011 shows flooded conditions. Land Floods January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing October 8, 2022JPEGOctober 3, 2023JPEGOctober 8, 2022October 3, 2023October 8, 2022JPEGOctober 3, 2023JPEGOctober 3, 2023JPEGJuly through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought.The OLI (Operational Land Imager) instrument on Landsat 8 captured this image (right) of the parched Rio Negro in the Brazilian province of Amazonas near the city of Manaus on October 3, 2023. On that date, the level of the river, the largest tributary of the Amazon River, had dropped to 15.14 meters (50.52 feet), according to data collected by the Port of Manaus. For comparison, the image on the left shows the same area on October 8, 2022, when the water level was 19.59 meters, a more typical level for October. Rio Negro water levels continued to drop in the days after the image was collected, reaching a record low of 13.49 meters on October 17, 2023.Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia.“Overall, this is a pretty unusual and extreme situation,” said René Garreaud, an atmospheric scientist at the University of Chile. “The primary culprit exacerbating the drought appears to be El Niño.” This cyclical warming of surface waters in the central-eastern Pacific functions somewhat like a boulder in the middle of a stream, disrupting atmospheric circulation patterns in ways that lead to wetter conditions over the equatorial Pacific and drier conditions over the Amazon Basin.According to news outlets, the low river water levels on the Rio Negro and other nearby rivers have disrupted drinking water supplies in hundreds of communities, slowed commercial navigation, and led to fish and dolphin die-offs.Manaus, the capital and largest city of the Brazilian state of Amazonas, is the primary transportation hub for the upper Amazon, serving as an important transit point for soap, beef, and animal hides. Other industries with a presence in the city of two million people include chemical, ship, and electrical equipment manufacturing.NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe water level of the largest tributary of the Amazon River has hit a record low.Image of the Day for October 18, 2023 Image of the Day Water Human Presence View more Images of the Day:The impact of severe drought on the Negro River, a tributary of the Amazon River, and other rivers in the basin is dramatically evident in this pair of images, which show that every body of water has shrunk in 2010 compared to 2008. Image of the Day Atmosphere Land The volume of water in New Mexico’s largest reservoir has dropped to historic lows due to drought and persistent demand. Image of the Day Water Human Presence Acquired June 25, 2011, and June 22, 2010, these false-color images compare conditions along the Souris River, which reached a historic crest at Minot, North Dakota in June 2011. Land Floods Acquired May 11, 2011, and April 21, 2007, these false-color images show the Mississippi River near Natchez, Mississippi. The image from May 2011 shows flooded conditions. Land Floods September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 6, 2020September 7, 2023September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter rapidly growing in volume just a few years earlier, northwest Iran’s Lake Urmia nearly dried out in autumn 2023. The largest lake in the Middle East and one of the largest hypersaline lakes on Earth at its greatest extent, Lake Urmia has for the most part transformed into a vast, dry salt flat. On September 7, 2023, the OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (right) of the desiccated lakebed. It stands in contrast to the image from three years earlier (left), acquired by the OLI on Landsat 8 on September 8, 2020, when water filled most of the basin and salt deposits were only visible around the perimeter of the lake. The replenishment followed a period of above-average precipitation that sent a surge of freshwater into the basin, expanding its watery footprint. Drier conditions have since brought levels back down. The longer-term trend for Urmia has been one toward drying. In 1995, Lake Urmia reached a high-water mark; then in the ensuing two decades, the lake level dropped more than 7 meters (23 feet) and lost approximately 90 percent of its area. Consecutive droughts, agricultural water use, and dam construction on rivers feeding the lake have contributed to the decline. A shrinking Lake Urmia has implications for ecological and human health. The lake, its islands, and surrounding wetlands comprise valuable habitat and are recognized as a UNESCO Biosphere Reserve, Ramsar site, and national park. The area provides breeding grounds for waterbirds such as flamingos, white pelicans, and white-headed ducks, as well as a stopover for migratory species. However, with low lake levels, what water remains becomes more saline and taxes the populations of brine shrimp and other food sources for larger animals. A shrinking lake also increases the likelihood of dust from the exposed lakebed becoming swept up by winds and degrading air quality. Recent studies have linked the low water levels in Lake Urmia with respiratory health impacts among the local population.The relative effects of climate, water usage, and dams on Lake Urmia’s water level is a topic of debate. The lake did see some recovery during a 10-year restoration program beginning in 2013. However, the efficacy of that effort has been difficult to parse since strong rains also fell during that period. Some research has concluded that climatic factors were primarily responsible for the recovery. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.View this area in EO ExplorerA few years after a fresh influx of water raised its levels, the large lake has nearly gone dry.Image of the Day for October 10, 2023 Image of the Day Land Water View more Images of the Day:Water levels are at their lowest since 1937. Image of the Day Water Drought Fires Long and short. Deep and shallow. Salty and fresh. Blue and brown. These are Africa’s Lake Tanganyika and Lake Rukwa. Image of the Day Land Water In May 2016, the reservoir behind Hoover Dam reached its lowest level since the 1930s. Image of the Day Water When the water gets saltier in Iran’s largest lake, the microscopic inhabitants can turn the water dark red. Image of the Day Water Water Color January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing October 8, 2022JPEGOctober 3, 2023JPEGOctober 8, 2022October 3, 2023October 8, 2022JPEGOctober 3, 2023JPEGOctober 3, 2023JPEGJuly through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought.The OLI (Operational Land Imager) instrument on Landsat 8 captured this image (right) of the parched Rio Negro in the Brazilian province of Amazonas near the city of Manaus on October 3, 2023. On that date, the level of the river, the largest tributary of the Amazon River, had dropped to 15.14 meters (50.52 feet), according to data collected by the Port of Manaus. For comparison, the image on the left shows the same area on October 8, 2022, when the water level was 19.59 meters, a more typical level for October. Rio Negro water levels continued to drop in the days after the image was collected, reaching a record low of 13.49 meters on October 17, 2023.Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia.“Overall, this is a pretty unusual and extreme situation,” said René Garreaud, an atmospheric scientist at the University of Chile. “The primary culprit exacerbating the drought appears to be El Niño.” This cyclical warming of surface waters in the central-eastern Pacific functions somewhat like a boulder in the middle of a stream, disrupting atmospheric circulation patterns in ways that lead to wetter conditions over the equatorial Pacific and drier conditions over the Amazon Basin.According to news outlets, the low river water levels on the Rio Negro and other nearby rivers have disrupted drinking water supplies in hundreds of communities, slowed commercial navigation, and led to fish and dolphin die-offs.Manaus, the capital and largest city of the Brazilian state of Amazonas, is the primary transportation hub for the upper Amazon, serving as an important transit point for soap, beef, and animal hides. Other industries with a presence in the city of two million people include chemical, ship, and electrical equipment manufacturing.NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe water level of the largest tributary of the Amazon River has hit a record low.Image of the Day for October 18, 2023 Image of the Day Water Human Presence View more Images of the Day:The impact of severe drought on the Negro River, a tributary of the Amazon River, and other rivers in the basin is dramatically evident in this pair of images, which show that every body of water has shrunk in 2010 compared to 2008. Image of the Day Atmosphere Land The volume of water in New Mexico’s largest reservoir has dropped to historic lows due to drought and persistent demand. Image of the Day Water Human Presence Acquired June 25, 2011, and June 22, 2010, these false-color images compare conditions along the Souris River, which reached a historic crest at Minot, North Dakota in June 2011. Land Floods Acquired May 11, 2011, and April 21, 2007, these false-color images show the Mississippi River near Natchez, Mississippi. The image from May 2011 shows flooded conditions. Land Floods September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 6, 2020September 7, 2023September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter rapidly growing in volume just a few years earlier, northwest Iran’s Lake Urmia nearly dried out in autumn 2023. The largest lake in the Middle East and one of the largest hypersaline lakes on Earth at its greatest extent, Lake Urmia has for the most part transformed into a vast, dry salt flat. On September 7, 2023, the OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (right) of the desiccated lakebed. It stands in contrast to the image from three years earlier (left), acquired by the OLI on Landsat 8 on September 8, 2020, when water filled most of the basin and salt deposits were only visible around the perimeter of the lake. The replenishment followed a period of above-average precipitation that sent a surge of freshwater into the basin, expanding its watery footprint. Drier conditions have since brought levels back down. The longer-term trend for Urmia has been one toward drying. In 1995, Lake Urmia reached a high-water mark; then in the ensuing two decades, the lake level dropped more than 7 meters (23 feet) and lost approximately 90 percent of its area. Consecutive droughts, agricultural water use, and dam construction on rivers feeding the lake have contributed to the decline. A shrinking Lake Urmia has implications for ecological and human health. The lake, its islands, and surrounding wetlands comprise valuable habitat and are recognized as a UNESCO Biosphere Reserve, Ramsar site, and national park. The area provides breeding grounds for waterbirds such as flamingos, white pelicans, and white-headed ducks, as well as a stopover for migratory species. However, with low lake levels, what water remains becomes more saline and taxes the populations of brine shrimp and other food sources for larger animals. A shrinking lake also increases the likelihood of dust from the exposed lakebed becoming swept up by winds and degrading air quality. Recent studies have linked the low water levels in Lake Urmia with respiratory health impacts among the local population.The relative effects of climate, water usage, and dams on Lake Urmia’s water level is a topic of debate. The lake did see some recovery during a 10-year restoration program beginning in 2013. However, the efficacy of that effort has been difficult to parse since strong rains also fell during that period. Some research has concluded that climatic factors were primarily responsible for the recovery. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.View this area in EO ExplorerA few years after a fresh influx of water raised its levels, the large lake has nearly gone dry.Image of the Day for October 10, 2023 Image of the Day Land Water View more Images of the Day:Water levels are at their lowest since 1937. Image of the Day Water Drought Fires Long and short. Deep and shallow. Salty and fresh. Blue and brown. These are Africa’s Lake Tanganyika and Lake Rukwa. Image of the Day Land Water In May 2016, the reservoir behind Hoover Dam reached its lowest level since the 1930s. Image of the Day Water When the water gets saltier in Iran’s largest lake, the microscopic inhabitants can turn the water dark red. Image of the Day Water Water Color July 1 - September 30, 2023MPEG For several months in 2023, global sea surface temperatures reached record-high levels, fueled by decades of human-caused climate warming and a recent boost from the natural climate phenomenon El Niño. Some areas—including the seas around Florida, Cuba, and the Bahamas—saw particularly high temperatures, with implications for the health of coral reefs.Corals thrive within a small range of temperatures and become stressed when water is too hot or cold. Bleaching occurs when stressed corals expel the algae that live inside them, stripping corals of their color. Extreme bleaching can leave a reef susceptible to starvation, disease, and even death. Observations made by divers in the Florida Keys found that the marine heatwave in summer 2023 caused widespread bleaching.Stress on corals can also be detected using data from satellites. This animation shows the evolution of accumulated heat stress from July through September 2023. The colors depict “degree heating weeks” (°C-weeks)—a measure that provides an estimate of the severity and duration of thermal stress. Data for the product are compiled by NOAA’s Coral Reef Watch, which blends observations from polar orbiting satellites such as the NASA-NOAA Suomi NPP, and from geostationary satellites such as GOES, with computer models.Observations have shown that when the accumulated heat stress reaches a value of 4, significant coral bleaching can result. At values of 8, coral bleaching and widespread mortality are likely. By midway through this animation, in August, heat stress across much of the region already soared well above both of those thresholds. According to NOAA, cumulative heat stress by late September 2023 hit 22°C-weeks (40°F-weeks), nearly triple the previous record for the region.Bleaching was already observed in some areas as early as July. Notice that areas of coral reef (gray) near the Florida Keys, Cuba, and the Bahamas, are among the first areas to show high cumulative heat stress. Hurricane Idalia in late August helped cool surface waters somewhat, but only temporarily.Nearing mid-October, waters around the Florida Keys were under a bleaching watch. Further south, waters around parts of Cuba and the Bahamas remained at bleaching alert level 2, the highest level of the scale, signifying that severe bleaching and mortality are likely.NASA Earth Observatory animation by Wanmei Liang, using Daily 5km Degree Heating Weeks data from Coral Reef Watch. Coral reef data from UNEP-WCMC, WorldFish Centre, WRI, TNC. Story by Kathryn Hansen.View this area in EO ExplorerThe seas around Florida, Cuba, and the Bahamas saw large accumulations of heat stress beginning in summer 2023, with implications for the health of coral reefs.Image of the Day for October 16, 2023 Image of the Day Water Temperature Extremes View more Images of the Day:Warmer-than-average temperatures are showing up locally and globally, with consequences for people, landscapes, and ecosystems. Image of the Day Water Image of the Day Life Water Image of the Day Heat Life Water Studying corals from above could help scientists understand how these critical ecosystems will weather a changing climate. Image of the Day Land Life Water January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing October 8, 2022JPEGOctober 3, 2023JPEGOctober 8, 2022October 3, 2023October 8, 2022JPEGOctober 3, 2023JPEGOctober 3, 2023JPEGJuly through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought.The OLI (Operational Land Imager) instrument on Landsat 8 captured this image (right) of the parched Rio Negro in the Brazilian province of Amazonas near the city of Manaus on October 3, 2023. On that date, the level of the river, the largest tributary of the Amazon River, had dropped to 15.14 meters (50.52 feet), according to data collected by the Port of Manaus. For comparison, the image on the left shows the same area on October 8, 2022, when the water level was 19.59 meters, a more typical level for October. Rio Negro water levels continued to drop in the days after the image was collected, reaching a record low of 13.49 meters on October 17, 2023.Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia.“Overall, this is a pretty unusual and extreme situation,” said René Garreaud, an atmospheric scientist at the University of Chile. “The primary culprit exacerbating the drought appears to be El Niño.” This cyclical warming of surface waters in the central-eastern Pacific functions somewhat like a boulder in the middle of a stream, disrupting atmospheric circulation patterns in ways that lead to wetter conditions over the equatorial Pacific and drier conditions over the Amazon Basin.According to news outlets, the low river water levels on the Rio Negro and other nearby rivers have disrupted drinking water supplies in hundreds of communities, slowed commercial navigation, and led to fish and dolphin die-offs.Manaus, the capital and largest city of the Brazilian state of Amazonas, is the primary transportation hub for the upper Amazon, serving as an important transit point for soap, beef, and animal hides. Other industries with a presence in the city of two million people include chemical, ship, and electrical equipment manufacturing.NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe water level of the largest tributary of the Amazon River has hit a record low.Image of the Day for October 18, 2023 Image of the Day Water Human Presence View more Images of the Day:The impact of severe drought on the Negro River, a tributary of the Amazon River, and other rivers in the basin is dramatically evident in this pair of images, which show that every body of water has shrunk in 2010 compared to 2008. Image of the Day Atmosphere Land The volume of water in New Mexico’s largest reservoir has dropped to historic lows due to drought and persistent demand. Image of the Day Water Human Presence Acquired June 25, 2011, and June 22, 2010, these false-color images compare conditions along the Souris River, which reached a historic crest at Minot, North Dakota in June 2011. Land Floods Acquired May 11, 2011, and April 21, 2007, these false-color images show the Mississippi River near Natchez, Mississippi. The image from May 2011 shows flooded conditions. Land Floods September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 6, 2020September 7, 2023September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter rapidly growing in volume just a few years earlier, northwest Iran’s Lake Urmia nearly dried out in autumn 2023. The largest lake in the Middle East and one of the largest hypersaline lakes on Earth at its greatest extent, Lake Urmia has for the most part transformed into a vast, dry salt flat. On September 7, 2023, the OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (right) of the desiccated lakebed. It stands in contrast to the image from three years earlier (left), acquired by the OLI on Landsat 8 on September 8, 2020, when water filled most of the basin and salt deposits were only visible around the perimeter of the lake. The replenishment followed a period of above-average precipitation that sent a surge of freshwater into the basin, expanding its watery footprint. Drier conditions have since brought levels back down. The longer-term trend for Urmia has been one toward drying. In 1995, Lake Urmia reached a high-water mark; then in the ensuing two decades, the lake level dropped more than 7 meters (23 feet) and lost approximately 90 percent of its area. Consecutive droughts, agricultural water use, and dam construction on rivers feeding the lake have contributed to the decline. A shrinking Lake Urmia has implications for ecological and human health. The lake, its islands, and surrounding wetlands comprise valuable habitat and are recognized as a UNESCO Biosphere Reserve, Ramsar site, and national park. The area provides breeding grounds for waterbirds such as flamingos, white pelicans, and white-headed ducks, as well as a stopover for migratory species. However, with low lake levels, what water remains becomes more saline and taxes the populations of brine shrimp and other food sources for larger animals. A shrinking lake also increases the likelihood of dust from the exposed lakebed becoming swept up by winds and degrading air quality. Recent studies have linked the low water levels in Lake Urmia with respiratory health impacts among the local population.The relative effects of climate, water usage, and dams on Lake Urmia’s water level is a topic of debate. The lake did see some recovery during a 10-year restoration program beginning in 2013. However, the efficacy of that effort has been difficult to parse since strong rains also fell during that period. Some research has concluded that climatic factors were primarily responsible for the recovery. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.View this area in EO ExplorerA few years after a fresh influx of water raised its levels, the large lake has nearly gone dry.Image of the Day for October 10, 2023 Image of the Day Land Water View more Images of the Day:Water levels are at their lowest since 1937. Image of the Day Water Drought Fires Long and short. Deep and shallow. Salty and fresh. Blue and brown. These are Africa’s Lake Tanganyika and Lake Rukwa. Image of the Day Land Water In May 2016, the reservoir behind Hoover Dam reached its lowest level since the 1930s. Image of the Day Water When the water gets saltier in Iran’s largest lake, the microscopic inhabitants can turn the water dark red. Image of the Day Water Water Color July 1 - September 30, 2023MPEG For several months in 2023, global sea surface temperatures reached record-high levels, fueled by decades of human-caused climate warming and a recent boost from the natural climate phenomenon El Niño. Some areas—including the seas around Florida, Cuba, and the Bahamas—saw particularly high temperatures, with implications for the health of coral reefs.Corals thrive within a small range of temperatures and become stressed when water is too hot or cold. Bleaching occurs when stressed corals expel the algae that live inside them, stripping corals of their color. Extreme bleaching can leave a reef susceptible to starvation, disease, and even death. Observations made by divers in the Florida Keys found that the marine heatwave in summer 2023 caused widespread bleaching.Stress on corals can also be detected using data from satellites. This animation shows the evolution of accumulated heat stress from July through September 2023. The colors depict “degree heating weeks” (°C-weeks)—a measure that provides an estimate of the severity and duration of thermal stress. Data for the product are compiled by NOAA’s Coral Reef Watch, which blends observations from polar orbiting satellites such as the NASA-NOAA Suomi NPP, and from geostationary satellites such as GOES, with computer models.Observations have shown that when the accumulated heat stress reaches a value of 4, significant coral bleaching can result. At values of 8, coral bleaching and widespread mortality are likely. By midway through this animation, in August, heat stress across much of the region already soared well above both of those thresholds. According to NOAA, cumulative heat stress by late September 2023 hit 22°C-weeks (40°F-weeks), nearly triple the previous record for the region.Bleaching was already observed in some areas as early as July. Notice that areas of coral reef (gray) near the Florida Keys, Cuba, and the Bahamas, are among the first areas to show high cumulative heat stress. Hurricane Idalia in late August helped cool surface waters somewhat, but only temporarily.Nearing mid-October, waters around the Florida Keys were under a bleaching watch. Further south, waters around parts of Cuba and the Bahamas remained at bleaching alert level 2, the highest level of the scale, signifying that severe bleaching and mortality are likely.NASA Earth Observatory animation by Wanmei Liang, using Daily 5km Degree Heating Weeks data from Coral Reef Watch. Coral reef data from UNEP-WCMC, WorldFish Centre, WRI, TNC. Story by Kathryn Hansen.View this area in EO ExplorerThe seas around Florida, Cuba, and the Bahamas saw large accumulations of heat stress beginning in summer 2023, with implications for the health of coral reefs.Image of the Day for October 16, 2023 Image of the Day Water Temperature Extremes View more Images of the Day:Warmer-than-average temperatures are showing up locally and globally, with consequences for people, landscapes, and ecosystems. Image of the Day Water Image of the Day Life Water Image of the Day Heat Life Water Studying corals from above could help scientists understand how these critical ecosystems will weather a changing climate. Image of the Day Land Life Water Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.Advertisement Scientific Data volume 7, Article number: 112 (2020) Cite this article 30k Accesses126 Citations88 AltmetricMetrics detailsRemotely sensed biomass carbon density maps are widely used for myriad scientific and policy applications, but all remain limited in scope. They often only represent a single vegetation type and rarely account for carbon stocks in belowground biomass. To date, no global product integrates these disparate estimates into an all-encompassing map at a scale appropriate for many modelling or decision-making applications. We developed an approach for harmonizing vegetation-specific maps of both above and belowground biomass into a single, comprehensive representation of each. We overlaid input maps and allocated their estimates in proportion to the relative spatial extent of each vegetation type using ancillary maps of percent tree cover and landcover, and a rule-based decision schema. The resulting maps consistently and seamlessly report biomass carbon density estimates across a wide range of vegetation types in 2010 with quantified uncertainty. They do so for the globe at an unprecedented 300-meter spatial resolution and can be used to more holistically account for diverse vegetation carbon stocks in global analyses and greenhouse gas inventories.Measurement(s)biomass carbon densityTechnology Type(s)digital curationFactor Type(s)climatic zone • above or below ground • land coverSample Characteristic - Environmentorganic materialSample Characteristic - LocationEarth (planet)Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.11872383Terrestrial ecosystems store vast quantities of carbon (C) in aboveground and belowground biomass1. At any point in time, these stocks represent a dynamic balance between the C gains of growth and C losses from death, decay and combustion. Maps of biomass are routinely used for benchmarking biophysical models2,3,4, estimating C cycle effects of disturbance5,6,7, and assessing biogeographical patterns and ecosystem services8,9,10,11. They are also critical for assessing climate change drivers, impacts, and solutions, and factor prominently in policies like Reducing Emissions from Deforestation and Forest Degradation (REDD+) and C offset schemes12,13,14. Numerous methods have been used to map biomass C stocks but their derivatives often remain limited in either scope or extent12,15. There thus remains a critical need for a globally harmonized, integrative map that comprehensively reports biomass C across a wide range of vegetation types.Most existing maps of aboveground biomass (AGB) and the carbon it contains (AGBC) are produced from statistical or data-driven methods relating field-measured or field-estimated biomass densities and spaceborne optical and/or radar imagery12,15,16. They largely focus on the AGB of trees, particularly those in tropical landscapes where forests store the majority of the region’s biotic C in aboveground plant matter. Land cover maps are often used to isolate forests from other landcover types where the predictive model may not be appropriate such that forest AGB maps intentionally omit AGB stocks in non-forest vegetation like shrublands, grasslands, and croplands, as well as the AGB of trees located within the mapped extent of these excluded landcovers17. Non-forest AGB has also been mapped to some extent using similar approaches but these maps are also routinely masked to the geographic extent of their focal landcover18,19,20,21. To date, there has been no rigorous attempt to harmonize and integrate these landcover-specific, remotely sensed products into a single comprehensive and temporally consistent map of C in all living biomass.Maps of belowground biomass (BGB) and carbon density (BGBC) are far less common than those of AGB because BGB cannot be readily observed from space or airborne sensors. Consequently, BGB is often inferred from taxa-, region-, and/or climate-specific “root-to-shoot” ratios that relate the quantity of BGB to that of AGB22,23,24. These ratios can be used to map BGB by spatially applying them to AGB estimates using maps of their respective strata5. In recent years, more sophisticated regression-based methods have been developed to predict root-to-shoot ratios of some landcover types based on covariance with other biophysical and/or ecological factors25,26. When applied spatially, these methods can allow for more continuous estimates of local BGB5,27. Like AGBC, though, few attempts have been made to comprehensively map BGBC for the globe.Despite the myriad of emerging mapping methods and products, to date, the Intergovernmental Panel on Climate Change (IPCC) Tier-1 maps by Ruesch and Gibbs28 remains the primary source of global AGBC and BGBC estimates that transcend individual landcover types. These maps, which represents the year 2000, were produced prior to the relatively recent explosion of satellite-based AGB maps and they therefore rely on an alternative mapping technique called “stratify and multiply”15, which assigns landcover-specific biomass estimates or “defaults” (often derived from field measurements or literature reviews) to the corresponding classified grid cells of a chosen landcover map12. While this approach yields a comprehensive wall-to-wall product, it can fail to capture finer-scale spatial patterns often evident in the field and in many satellite-based products12,15. The accuracy of these maps is also tightly coupled to the quality and availability of field measurements29 and the thematic accuracy and discontinuity of the chosen landcover map.Given the wealth of landcover-specific satellite based AGB maps, a new harmonization method akin to “stratify and multiply” is needed to merge the validated spatial detail of landcover-specific remotely sensed biomass maps into a single, globally harmonized product. We developed such an approach by which we (i) overlay distinct satellite-based biomass maps and (ii) proportionately allocate their estimates to each grid cell (“overlay and allocate”). Specifically, we overlay continental-to-global scale remotely sensed maps of landcover-specific biomass C density and then allocate fractional contributions of each to a given grid cell using additional maps of percent tree cover, thematic landcover and a rule-based decision tree. We implement the new approach here using temporally consistent maps of AGBC as well as matching derived maps of BGBC to generate separate harmonized maps of AGBC and BGBC densities. In addition, we generate associated uncertainty layers by propagating the prediction error of each input dataset. The resulting global maps consistently represent biomass C and associated uncertainty across a broad range of vegetation in the year 2010 at an unprecedented 300 meter (m) spatial resolution.Our harmonization approach (Fig. 1) relies on independent, landcover-specific biomass maps and ancillary layers, which we compiled from the published literature (Table 1). When published maps did not represent our epoch of interest (i.e. grasslands and croplands) or did not completely cover the necessary spatial extent (i.e. tundra vegetation), we used the predictive model reported with the respective map to generate an updated version that met our spatial and temporal requirements. We then used landcover specific root-to-shoot relationships to generate matching BGBC maps for each of the input AGBC maps before implementing the harmonization procedure. Below we describe, in detail, the methodologies used for mapping AGBC and BGBC of each landcover type and the procedure used to integrate them.Generalized, three-step workflow used to create harmonized global biomass maps. In step one, woody AGB maps are prepared, combined, converted to AGBC density and used to create separate but complementary maps of BGBC. In step two, a similar workflow is used to generate matching maps of AGBC and BGBC for tundra vegetation, grasses, and annual crops. In step three, all maps are combined using a rule-based decision tree detailed in Fig. 3 to generate comprehensive, harmonized global maps. All input data sources are listed and described in Table 1.Since the first remotely sensed woody AGB maps were published in the early 1990s, the number of available products has grown at an extraordinary pace16 and it can thus be challenging to determine which product is best suited for a given application. For our purposes, we relied on the GlobBiomass AGB density map30 as our primary source of woody AGB estimates due to its precision, timestamp, spatial resolution, and error quantification. It was produced using a combination of spaceborne optical and synthetic aperture radar (SAR) imagery and represents the year 2010 at a 100 m spatial resolution – making it the most contemporary global woody AGB currently available and the only such map available for that year. Moreover, GlobBiomass aims to minimize prediction uncertainty to less than 30% and a recent study suggests that it has high fidelity for fine-scale applications31.The GlobBiomass product was produced by first mapping the growing stock volume (GSV; i.e. stem volume) of living trees, defined following Food and Agriculture Organization (FAO) guidelines32 as those having a diameter at breast height (DBH) greater than 10 centimeters (cm). AGB density was then determined from GSV by applying spatialized biomass expansion factors (BEFs) and wood density estimates. These factors were mapped using machine learning methods trained from a suite of plant morphological databases that compile thousands of field measurements from around the globe33. The resulting AGB estimates represent biomass in the living structures (stems, branches, bark, twigs) of trees with a DBH greater than 10 cm. This definition may thereby overlook AGB of smaller trees and/or shrubs common to many global regions. Unlike other maps, though, the GlobBiomass product employs a subpixel masking procedure that retains AGB estimates in 100 m grid cells in which any amount of tree cover was detected in finer resolution (30 m) imagery34. This unique procedure retains AGB estimates in tree-sparse regions like savannahs, grasslands, croplands, and agroforestry systems where AGB is often overlooked17, as well as in forest plantations. The GlobBiomass product is the only global map that also includes a dedicated uncertainty layer reporting the standard error of prediction. We used this layer to propagate uncertainty when converting AGB to AGBC density, modelling BGBC, and integrating with C density estimates of other vegetation types.Bouvet et al.35 – some of whom were also participants of the GlobBiomass project – independently produced a separate AGB density map for African savannahs, shrublands and dry woodlands circa 2010 at 25 m spatial resolution35 (hereafter “Bouvet map”), which we included in our harmonized product to begin to address the GlobBiomass map’s potential omission of small trees and shrubs that do not meet the FAO definition of woody AGB. This continental map of Africa is based on a predictive model that directly relates spaceborne L-band SAR imagery – an indirect measure of vegetation structure that is sensitive to low biomass densities36 – with region-specific, field-measured AGB. Field measurements (n = 144 sites) were compiled from 7 different sampling campaigns – each specifically seeking training data for biomass remote sensing – that encompassed 8 different countries35. The resulting map is not constrained by the FAO tree definition and is masked to exclude grid cells in which predicted AGB exceeds 85 megagrams dry mater per hectare (Mg ha−1) – the threshold at which the SAR-biomass relationship saturates. To avoid extraneous prediction, it further excludes areas identified as “broadleaved evergreen closed-to-open forest”, “flooded forests”, “urban areas” and “water bodies” by the European Space Agency’s Climate Change Initiative (CCI) Landcover 2010 map37 and as “bare areas” in the Global Land Cover (GLC) 2000 map38. While the Bouvet map is not natively accompanied by an uncertainty layer, its authors provided us with an analytic expression of its uncertainty (SE; standard error of prediction) as a function of estimated AGB (Eq. 1) which we used to generate an uncertainty layer for subsequent error propagation.We combined the GlobBiomass and Bouvet products to generate a single woody biomass map by first upscaling each map separately to a matching 300 m spatial resolution using an area-weighted average to aggregate grid cells, and then assigning the Bouvet estimate to all overlapping grid cells, except those identified by the CCI Landcover 2010 map as closed or flooded forest types (Online-only Table 1) which were not within the dryland domain of the Bouvet map. While more complex harmonization procedures based on various averaging techniques have been used by others39,40, their fidelity remains unclear since they fail to explicitly identify and reconcile the underlying source of the inputs’ discrepancies41. We thus opted to use a more transparent ruled-based approach when combining these two woody biomass maps, which allows users to easily identify the source of a grid cell’s woody biomass estimate. Given the local specificity of the training data used to produce the Bouvet map, we chose to prioritize its predictions over those of the GlobBiomass product when within its domain. In areas of overlap, the Bouvet map values tend to be lower in moist regions and higher in dryer regions (Fig. 2), though, where used, these differences rarely exceed ±25 megagrams C per hectare (MgC ha−1).Difference between underlying woody aboveground biomass maps in Africa. Maps considered are the GlobBiomass30 global map and the Bouvet35 map of Africa. Both maps were aggregated to a 300 m spatial resolution and converted to C density prior to comparison using the same schema. The difference map was subsequently aggregated to a 3 km spatial resolution and reprojected for visualization. Negative values denote lower estimates by Bouvet et al.35, while positive values denote higher estimates.We then converted all woody AGB estimates to AGBC by mapping climate and phylogeny-specific biomass C concentrations from Martin et al.42. Climate zones were delineated by aggregating classes of the Köppen-Gieger classification43 (Table 2) to match those of Martin et al.42. Phylogenetic classes (angiosperm, gymnosperm and mixed/ambiguous) were subsequently delineated within each of these zones using aggregated classes of the CCI Landcover 2010 map (Online-only Table 1). Martin et al.42 only report values for angiosperms and gymnosperms so grid cells with a mixed or ambiguous phylogeny were assigned the average of the angiosperm and gymnosperm values and the standard error of this value was calculated from their pooled variance. Due to residual classification error in the aggregated phylogenetic classes, we weighted the phylogeny-specific C concentration within each climate zone by the binary probability of correctly mapping that phylogeny (i.e. user’s accuracy)44 using Eq. 2where, within each climate zone, μc is the mean probability-weighted C concentration of the most probable phylogeny, μm is the mean C concentration of that phylogeny from Martin et al.42, pm is the user’s accuracy of that phylogeny’s classification (Table 3), and μn and μo are the mean C concentrations of the remain phylogenetic classes from Martin et al.42. Standard error estimates for these C concentrations were similarly weighted using summation in quadrature (Eq. 3)where \({\sigma }_{c}\) is the probability-weighted standard error of the most probable phylogeny’s C concentration and \({\sigma }_{m}\), \({\sigma }_{n}\) and \({\sigma }_{o}\) are the standard errors of the respective phylogeny-specific C concentrations from Martin et al.42. Probability-weighted C concentrations used are reported in Table 4.Mapped, probability-weighted C estimates were then arithmetically applied to AGB estimates. Uncertainty associated with this correction was propagated using summation in quadrature of the general form (Eq. 4)where \({\mu }_{f}=f(i,j,\ldots ,k)\), \({\sigma }_{f}\) is the uncertainty of μf, and \({\sigma }_{i},{\sigma }_{j},\ldots ,{\sigma }_{k}\), are the respective uncertainty estimates of the dependent parameters (standard error unless otherwise noted). Here, μf, is the estimated AGBC of a given grid cell, and is the product of its woody AGB estimate, and its corresponding C concentration.The tundra and portions of the boreal biome are characterized by sparse trees and dwarf woody shrubs as well as herbaceous cover that are not included in the GlobBiomass definition of biomass. AGB density of these classes has been collectively mapped by Berner et al.18,45 for the North Slope of Alaska from annual Landsat imagery composites of the normalized difference vegetation index (NDVI) and a non-linear regression-based model trained from field measurements of peak AGB that were collected from the published literature (n = 28 sites). Berner et al.18 note that while these field measurements did not constitute a random or systematic sample, they did encompass a broad range of tundra plant communities. In the absence of a global map and due the sparsity of high quality Landsat imagery at high latitudes, we extended this model to the pan-Arctic and circumboreal regions using NDVI composites created from daily 250 m MODIS Aqua and Terra surface reflectance images46,47 that were cloud masked and numerically calibrated to Landsat ETM reflectance – upon which the tundra model is based – using globally derived conversion coefficients48. We generated six separate 80th percentile NDVI composites circa 2010 – one for each of the MODIS missions (Aqua and Terra) in 2009, 2010 and 2011 – following Berner et al.18. We chose to use three years of imagery (circa 2010) rather than just one (2010) to account for the potential influence that cloud masking may exert upon estimates of the 80th NDVI percentile in a single year. We then applied the tundra AGB model to each composite, converted AGB estimates to AGBC by assuming a biomass C fraction of 49.2% (SE = 0.8%)42 and generated error layers for each composite from the reported errors of the AGB regression coefficients and the biomass C conversion factor using summation in quadrature as generally described above (Eq. 4). A single composite of tundra AGBC circa 2010 was then created as the pixelwise mean of all six composites. We also generated a complementary uncertainty layer representing the cumulative standard error of prediction, calculated as the pixelwise root mean of the squared error images in accordance with summation in quadrature. Both maps were upscaled from their native 250 m spatial resolution to a 300 m spatial resolution using an area weighted aggregation procedure, whereby pixels of the 300 m biomass layer was calculated as the area weighted average of contained 250 m grid cells, and the uncertainty layer was calculated – using summation in quadrature – as the root area-weighted average of the contained grid cells squared.Grassland AGBC density was modelled directly from maximum annual NDVI composites using a non-linear regression-based model developed by Xia et al.19 for mapping at the global scale. This model was trained by relating maximum annual NDVI as measured by the spaceborne Advanced Very High-Resolution Radiometer (AVHRR) sensor to globally distributed field measurements of grassland AGBC that were compiled from the published literature (81 sites for a total of 158 site-years). Like the tundra biomass training data, these samples did not constitute a random or systematic sample but do encompass a comprehensive range of global grassland communities. Given the inevitable co-occurrence of trees in the AVHRR sensor’s 8 km resolution pixels upon which the model is trained, it’s predictions of grassland AGBC are relatively insensitive to the effects of co-occurring tree cover. We thereby assume that its predictions for grid cells containing partial tree cover represent the expected herbaceous AGBC density in the absence of those trees. Maximum model predicted AGBC (NDVI = 1) is 2.3 MgC ha−1 which is comparable to the upper quartile of herbaceous AGBC estimates from global grasslands49 and suggests that our assumption will not lead to an exaggerated estimation. For partially wooded grid cells, we used modelled grassland AGBC density to represent that associated with the herbaceous fraction of the grid cell in a manner similar to Zomer et al.17 as described below (See “Harmonizing Biomass Carbon Maps”).We applied the grassland AGBC model to all grid cells of maximum annual NDVI composites produced from finer resolution 16-day (250 m) MODIS NDVI imagery composites circa 201050,51. Here again, three years of imagery were used to account for potential idiosyncrasies in a single year’s NDVI composites resulting from annual data availability and quality. As with AGB of tundra vegetation, annual composites (2009–2011) were constructed separately from cloud-masked imagery collected by both MODIS missions (Aqua and Terra; n = 6) and then numerically calibrated to AVHRR reflectance using globally derived conversion coefficients specific to areas of herbaceous cover52. We then applied the AGBC model to each of these composites and estimated error for each composite from both the AVHRR calibration (standard deviation approximated from the 95% confidence interval of the calibration scalar) and the AGBC model (relative RMSE) using summation in quadrature. A single map of grassland AGBC circa 2010 was then created as the pixelwise mean of all six composites and an associated error layer was created as the pixelwise root mean of the squared error images. Both maps were aggregated from their original 250 m resolution to 300 m to facilitate harmonization using the area-weighted procedure described previously for woody and tundra vegetation (see section 1.2).Prior to harvest, cropland biomass can also represent a sizable terrestrial C stock. In annually harvested cropping systems, the maximum standing biomass of these crops can be inferred from annual net primary productivity (ANPP). While spaceborne ANPP products exist, they generally perform poorly in croplands53,54. Instead, cropland ANPP is more commonly derived from crop yields20,21,53. We used globally gridded, crop-specific yields of 70 annually harvested herbaceous commodity crops circa 2000 by Monfreda et al.20 – the only year in which these data were available. These maps were produced by spatially disaggregating crop-yield statistics for thousands of globally distributed administrative units throughout the full extent of a satellite-based cropland map20. These maps were combined with crop-specific parameters (Online-only Table 2) to globally map AGBC as aboveground ANPP for each crop following the method of Wolf et al.21. This method can be simplified as (Eq. 5)where y is the crop’s yield (Mg ha−1), ω is the dry matter fraction of its harvested biomass, h is its harvest index (fraction of total AGB collected at harvest) and c is the carbon content fraction of its harvested dry mass. This simplification assumes, following Wolf et al.21, that 2.5% of all harvested biomass is lost between the field and farmgate and that unharvested residue and root mass is 44% C.Total cropland AGBC density was then calculated as the harvested-area-weighted average of all crop-specific AGBC estimates within a given grid cell. Since multiple harvests in a single year can confound inference of maximum AGBC from ANPP, we further determined the harvest frequency (f) of each grid cell by dividing a cell’s total harvested area (sum of the harvested area of each crop reported within a given grid cell) by its absolute cropland extent as reported in a complementary map by Ramankutty et al.55. If f was greater than one, multiple harvests were assumed to have occurred and AGBC was divided by f to ensure that AGBC estimates did not exceed the maximum standing biomass density.Since the yields of many crops and, by association, their biomass have changed considerably since 200056,57, we calibrated our circa 2000 AGBC estimates to the year 2010 using local rates of annual ANPP change (MgC ha−1 yr−1) derived as the Theil-Sen slope estimator – a non-parametric estimator that is relatively insensitive to outliers – of the full MODIS Terra ANPP timeseries (2000–2015)58. Total ANPP change between 2000 and 2010 for each grid cell was calculated as ten times this annual rate of change. Since MODIS ANPP represents C gains in both AGB and BGB, we proportionately allocated aboveground ANPP to AGBC using the total root-to-shoot ratio derived from the circa 2000 total crop AGBC and BGBC maps (described below). Since error estimates were not available for the yield maps or the crop-specific parameters used to generate the circa 2000 AGBC map, estimated error of the circa 2010 crop AGBC map was exclusively based on that of the 2000–2010 correction. The error of this correction was calculated as the pixel-wise standard deviation of bootstrapped simulations (n = 1000) in which a random subset of years was omitted from the slope estimator in each iteration. The 8 km resolution circa 2000 AGBC map and error layer were resampled to 1 km to match the resolution of MODIS ANPP using the bilinear method prior to ANPP correction and then further resampled to 300 m to facilitate harmonization.Woody crops like fruit, nut, and palm oil plantations were not captured using the procedure just described and their biomass was instead assumed to be captured by the previously described woody biomass products which retained biomass estimates in all pixels where any amount of tree cover was detected at the sub-pixel level (see section 1.1).Matching maps of BGBC and associated uncertainty were subsequently produced for each of the landcover-specific AGBC maps using published empirical relationships.With the exception of savannah and shrubland areas, woody BGBC was modelled from AGBC using a multiple regression model by Reich et al.25 that considers the phylogeny, mean annual temperature (MAT), and regenerative origin of each wooded grid cell and that was applied spatially using maps of each covariate in a fashion similar to other studies5,27. Tree phylogeny (angiosperm or gymnosperm) was determined from aggregated classes of the CCI Landcover 2010 map37 (Online-only Table 1) with phylogenetically mixed or ambiguous classes assumed to be composed of 50% of each. MAT was taken from version 2 of the WorldClim bioclimatic variables dataset (1970–2000) at 1 km resolution59 and resampled to 300 m using the bilinear method. Since there is not a single global data product mapping forest management, we determined tree origin – whether naturally propagated or planted – by combining multiple data sources. These data included (i) a global map of “Intact Forest Landscapes” (IFL) in the year 201360 (a conservative proxy of primary, naturally regenerating forests defined as large contiguous areas with minimal human impact), (ii) a Spatial Database of Planted Trees (SDPT) with partial global coverage61, (iii) national statistics reported by the FAO Global Forest Resources Assessment (FRA) on the extent of both naturally regenerating and planted forests and woodlands within each country in the year 201062, and (iv) national statistics reported by the FAOSTAT database (http://www.fao.org/faostat) on the planted area of plantation crops in 2010. Within each country, we assumed that the total area of natural and planted trees was equal to the corresponding FRA estimates. If the FAOSTAT-reported area of tree crops exceeded FRA-reported planted area, the difference was added to FRA planted total. All areas mapped as IFL were assumed to be of natural origin and BGB was modelled as such. Likewise, besides the exceptions noted below, all tree plantations mapped by the SDPT were assumed to be of planted origin. In countries where the extent of the IFL or SDPT maps fell short of the FRA/FAOSTAT reported areas of natural or planted forests, respectively, we estimated BGBC in the remaining, unknown-origin forest grid cells of that country (BGBCu), as the probability-weighted average of the planted and natural origin estimates using Eq. 6where \(BGB{C}_{p}\) and \(BGB{C}_{n}\) are the respective BGBC estimates for a grid cell assuming entirely planted and natural origin, respectively, and \({\Delta }_{p}\) and \({\Delta }_{n}\) are the respective differences between (i) the FRA/FAOSTAT and (ii) mapped extent of planted and natural forest within the given grid cell’s country. While the mapped extent of IFL forests within a given country never exceeded that country’s FRA reported natural forest extent, there were infrequent cases (n = 22 of 257) in which the mapped extent of tree plantations exceeded the corresponding FRA/FAOSTAT estimate of planted forest area. In these cases, we down-weighted the BGB estimates of SDPT forests in a similar fashion such that the weight of their planted estimate (\({\omega }_{p}\)) was equal to the quotient of (i) the FRA/FAOSTAT planted area and (ii) the SDPT extent within the country, and the weight of the natural origin estimate applied to the SDPT extent (\({\omega }_{n}\)) was equal to \(1-{\omega }_{p}\).A BGBC error layer was then produced using summation in quadrature from the standard error estimates of the model coefficients, the AGBC error layer, the relative RMSE of MAT (27%), and the derived global uncertainty of the phylogeny layer. Phylogeny error was calculated as the Bernoulli standard deviation (δ) of the binary probability (p) of correct classification (i.e. “area weighted user’s accuracy”44; Table 3) using Eq. 7.Since savannahs and shrublands are underrepresented in the regression-based model25, their BGBC was instead estimated using static root-to-shoot ratios reported by Mokany et al.22, which are somewhat conservative in comparison to the IPCC Tier-1 defaults23,24 put favoured for consistency with methods used for grasslands (see below). Error was subsequently mapped from that of the AGBC estimates and the root-to-shoot ratios applied (Table 5).BGBC of tundra vegetation was mapped from AGBC using a univariate regression model derived by Wang et al.26 that predicts root-to-shoot ratio as a function of MAT. We applied the model using the WorldClim version 2 MAT map59 and propagated error from the AGBC estimates, the relative RMSE of MAT and the standard error of regression coefficients. Where tundra AGB exceeded 25 Mg ha−1 – the maximum field-measured shrub biomass reported by Berner et al.18 – vegetation was considered to include trees and the Reich et al.25 method described earlier for woody vegetation was used instead.In the absence of a continuous predictor of grassland root-to-shoot ratios, we applied climate specific root-to-shoot ratios from Mokany et al.22 to the corresponding climate regions of the Köppen-Gieger classification43 (Table 2). Here, again, these ratios vary slightly from the IPCC Tier-1 defaults23,24 but were chosen for their greater sample size and specificity. Grassland BGBC error was mapped from the error of the AGBC estimates and the respective root-to-shoot ratios.Cropland BGBC was again estimated from crop-specific yields and morphological parameters (Online-only Table 2) following Wolf et al.21 and Eq. 8where y is the crop’s yield (Mg ha−1), r is the root-to-shoot ratio of the crop, and h is its harvest index. Here again we assume that 2.5% of all harvested biomass is lost between the field and farmgate and that root biomass is 44% C, following Wolf et al.21. BGBC error was mapped from the error of the 2000-to-2010 ANPP correction for BGBC allocation as described above for cropland AGBC.The AGBC and BGBC maps were harmonized separately following the same general schema (Fig. 3). Given that our harmonized woody biomass map contains biomass estimates for grid cells in which any amount of tree cover was detected at the subpixel level (see section 1.1), we conserved its estimates regardless of the landcover reported by the 2010 CCI map in order to more fully account for woody biomass in non-forested areas17. We then used the MODIS continuous vegetation fields percent tree cover map for 201063 to allocate additional biomass density associated with the most probable herbaceous cover (grass or crop) to each grid cell in quantities complementary to that of the grid cell’s fractional tree cover estimate (Eq. 9)where μT is the total biomass estimate of a grid cell, μw is the woody biomass estimate for the grid cell, μh is its herbaceous biomass estimate, and q is the MODIS fractional tree cover of the grid cell. Since MODIS tree cover estimates saturate at around 80%64, we linearly stretched values such that 80% was treated as complete tree cover (100%). Moreover, we acknowledge that percent cover can realistically exceed 100% when understory cover is considered but we were unable to reasonably determine the extent of underlying cover from satellite imagery. As such, our approach may underestimate the contribution of herbaceous C stocks in densely forested grid cells. The most likely herbaceous cover type was determined from the CCI Landcover 2010 map, which we aggregated into two “likely herbaceous cover” classes – grass or crop – based on the assumed likelihood of cropland in each CCI class (Online-only Table 1). However, due to inherent classification error in the native CCI Landcover map, when determining the herbaceous biomass contribution we weighted the relative allocation of crop and grass biomass to a given grid cell based on the probability of correct classification by the CCI map (i.e. “user’s accuracy”, Table 6) of the most probable herbaceous class (\({p}_{i}\)) such that μh can be further expressed as (Eq. 10)where μi is the predicted biomass of the most probable herbaceous class, and μj is that of the less probable class.Decision tree used to allocate landcover-specific biomass estimates to each grid cell of our harmonized global products.The uncertainty of a grid cell’s total AGBC or BGBC estimate (\({\sigma }_{T}\)) was determined and mapped from that of its components (\({\mu }_{w}\,{\rm{and}}\,{\mu }_{h}\)) by summation in quadrature which can be simplified as (Eq. 11)where \({\sigma }_{w}\) is the error of the grid cell’s estimated μw, \({\sigma }_{h}\) is the error of its estimated μh, and \({\sigma }_{q}\) is the error of its q. Here, \({\sigma }_{h}\) can be further decomposed and expressed as Eq. 12 to account for the accuracy weighted allocation procedure expressed previously (Eq. 10)where \({\sigma }_{i}\) is the error of the estimated biomass density of the most probable herbaceous class, \({\delta }_{i}\) is the estimated standard deviation of that class’s Bernoulli probability (p; Eq. 7), and \({\sigma }_{j}\) is the error of the estimated biomass density of the less probable herbaceous subclass.Exceptions to the above schema were made in the tundra and boreal biomes – as delineated by the RESOLVE Ecoregions 2017 biome polygons65 – where thematic overlap was likely between the woody and tundra plant biomass maps. A separate set of decision rules (Fig. 3) was used to determine whether grid cells in these biomes were to be exclusively allocated the estimate of the tundra plant map or that of the fractional allocation procedure described above. In general, any land in these biomes identified as sparse landcover by the CCI landcover map (Online-only Table 1) was assigned the tundra vegetation estimate. In addition, lands north of 60° latitude with less than 10% tree cover or where the tundra AGBC estimate exceeded that of the woody AGBC estimate were also exclusively assigned the tundra vegetation estimate. Lands north of 60° latitude not meeting these criteria were assigned the woody value with the additional contribution of grass.Subtle numerical artefacts emerged from the divergent methodologies employed north and south of 60°N latitude. These were eliminated by distance weighting grid cells within 1° of 60°N based on their linear proximity to 60°N and then averaging estimates such that values at or north of 61°N were exclusively based on the northern methodology, those at 60°N were the arithmetic average of the two methodologies and those at or south of 59°N were exclusively based on the southern methodology. This produced a seamless, globally harmonized product that integrates the best remotely sensed estimates of landcover-specific C density. Water bodies identified as class “210” of the CCI 2010 landcover map were then masked from our final products.Data layers (n = 4, Table 7) for the maps of AGBC and BGBC density (Fig. 4) as well as their associated uncertainty maps which represent the combined standard error of prediction (Fig. 5) are available as individual 16-bit integer rasters in GeoTiff format. All layers are natively in a WGS84 Mercator projection with a spatial resolution of approximately 300 m at the equator and match that of the ESA CCI Landcover Maps37. Raster values are in units megagrams C per hectare (MgC ha−1) and have been scaled by a factor of ten to reduce file size. These data are accessible through the Oak Ridge National Laboratory (ORNL) DAAC data repository (https://doi.org/10.3334/ORNLDAAC/1763)66. In addition, updated and/or derived vegetation-specific layers that were used to create our harmonized 2010 maps are available as supplemental data on figshare67.Globally harmonized maps of above and belowground living biomass carbon densities. (a) Aboveground biomass carbon density (AGBC) and (b) belowground biomass carbon density (BGBC) are shown separately. Maps have been aggregated to a 5 km spatial resolution and reprojected here for visualization.Uncertainty of grid cell level above and belowground biomass carbon density estimates. Uncertainty is shown here as the coefficient of variation (%; standard error layer divided by mean estimate layer) of estimated AGBC (a) and BGBC (b) densities after harmonization. Maps have been aggregated to a 5 km spatial resolution and projected for visualization.Our harmonized products rely almost exclusively upon maps and models that have been rigorously validated by their original producers and were often accompanied by constrained uncertainty estimates. Throughout our harmonization procedure, we strived to conserve the validity of each of these products by minimizing the introduction of additional error and by tracking any introductions, as described above, such that the final error layers represent the cumulative uncertainty of the inputs used. Ground truth AGB and BGB data are almost always collected for individual landcover types. Consequently, we are unable to directly assess the validity of our integrated estimates beyond their relationships to individual landcover-specific estimates and the extents to which they were modified from their original, previously-validated form prior to and during our harmonization procedure.Temporal and spatial updates made to existing landcover-specific maps of non-tree AGB resulted in relatively small changes to their predictions. For example, we used numerically calibrated MODIS imagery to extend the Landsat-based tundra plant AGB model beyond its native extent (the North Slope of Alaska) to the pan-Arctic region since neither a comparable model nor a consistent Landsat time series were available for this extent. We assessed the effects of these assumptions by comparing our predictions for the North Slope with those of the original map18 (Fig. 6a). Both positive and negative discrepancies exist between ours and the original, though these rarely exceed ±2 MgC ha−1 and no discernibly systematic bias was evident.Differences between landcover-specific AGBC estimates from the original published maps and the modified versions used as inputs to create the 2010 harmonized global maps. Tundra vegetation AGBC (a) is compared to the Landsat-based map of Berner et al.45 for the north slope of Alaska after converting it to units MgC ha−1. Here, the comparison map was subsequently aggregated to a 1 km resolution and reprojected for visualization. Grassland AGBC (b) is compared to the AVHRR-based map of Xia et al.19 which represents the average estimate between 1982–2006. For visualization, the map was aggregated to a 5 km resolution and subsequently reprojected after being masked to MODIS IGBP grasslands in the year 200685 following Xia et al.19. As such, this map does not necessarily represent the spatial distribution of grid cells in which grassland estimates were used. Cropland AGBC (c) is compared to the original circa 2000 estimates to assess the effects of the 2000-to-2010 correction. The map is masked to the native extent of the combined yield maps and aggregated to a 5 km resolution for visualization. For all maps, negative values indicate that our circa 2010 estimates are lower than those of the earlier maps while positive values indicate higher estimates.Our updated map of grassland biomass carbon in the year 2010 was similarly made by applying the original AVHRR-based model to calibrated MODIS imagery. This too resulted in only subtle changes to the original biomass map (Fig. 6b) that were rarely in excess of 0.5 MgC ha−1. In most areas, our estimates were higher than those of Xia et al.19 who mapped the mean AGBC density between 1986 and 2006. Most of these elevated estimates corresponded with areas in which significant NDVI increases (“greening”) have been reported while notably lower estimates in the Argentine Monte and Patagonian steppe biomes of southern South America, likewise, correspond with areas of reported “browning”68,69. Both greening and browning trends are well documented phenomena and have been linked to climatic changes70. Moreover, we further compared AGBC estimates from both the original Xia et al.19 map and our 2010 update to AGBC field measurements coordinated by the Nutrient Network that were collected from 48 sites around the world between 2007 and 200949. The RMSE (0.68 MgC ha−1) of our updated map was 10% less that of the Xia et al. map for sites with less than 40% tree cover. Likewise, our 2010 estimates were virtually unbiased (bias = −0.01 MgC ha−1) in comparison to the Xia map (bias = 0.25 MgC ha−1). While still noisy, these results suggest that our temporal update improved the overall accuracy of estimated grassland AGBC.Finally, cropland biomass carbon maps were also updated from their native epoch (2000) to 2010 using pixel-wise rates of MODIS ANPP change over a ten-year period. While MODIS ANPP may be a poor snapshot of crop biomass in a single year, we assumed that its relative change over time reflects real physiological shifts affecting the cropland C cycle. This correction also resulted in only small differences that rarely exceeded ±2 MgC ha−1 and that, spatially, correspond well with observed declines in the yields of select crops that have been linked to climate change71,72 (Fig. 6c). Nonetheless, updated global yield maps comparable to those available for 2000 would greatly improve our understanding of the interactions between climate change, crop yields, and C dynamics.Belowground biomass is notoriously difficult to measure, model, and also to validate. We accounted for the reported uncertainty of nearly every variable considered when estimating belowground biomass and pixel-level uncertainty, but we were unable to perform an independent validation of our harmonized estimates at the pixel level due to a paucity of globally consistent field data. To complete such a task, a globally orchestrated effort to collect more BGB samples data across all vegetation types is needed.Given this lack of data, we instead compared the estimated uncertainty of our BGBC maps to that of our AGBC estimates to infer the sources of any divergence (Fig. 5). As expected, our cumulative BGBC uncertainty layer generally reveals greater overall uncertainty than our AGBC estimates, with BGBC uncertainty roughly twice that of AGBC throughout most of the globe. The highest absolute uncertainty was found in biomass rich forests. Arid woodlands, especially those of the Sahel and eastern Namibia, generally had the greatest relative BGBC uncertainty, though their absolute uncertainty was quite small (generally less than 3 MgC ha−1). Here, biomass estimates of sparse woody vegetation were primarily responsible for heightened relative uncertainty. High relative and absolute BGBC uncertainty were also associated with predictions in select mountainous forests (e.g. east central Chile) as well as forested areas in and around cities. These patterns were largely driven by AGB uncertainty in the GlobBiomass product.The GlobBiomass global woody AGB map produced by Santoro et al.30 comprises the backbone of our integrated products and, with few exceptions, remains largely unchanged in our final AGBC map. The native version of the GlobBiomass map is accompanied by an error layer describing the uncertainty of each pixel’s biomass estimate and this too forms the core of our integrated uncertainty layers. In areas with tree cover, the global average error of GlobBiomass estimates is 39 Mg ha−1 or 50% with greater relative uncertainty in densely forested areas, along the margins of forested expanses like farm fields and cities, and in similar areas with sparse tree cover.Adding additional grass or crop biomass in complementary proportion to a grid cell’s tree cover often did not exceed the estimated error of the original GlobBiomass map (Fig. 7). Grid cells exceeding GlobBiomass’s native uncertainty comprise less than 40% of its total extent. Exceptions were primarily found in grassland and cropland dominated regions where tree cover was generally sparse, and, consequently, the herbaceous biomass contribution was relatively high. Even so, the absolute magnitude of these additions remains somewhat small (less than 2.3 MgC ha−1 for grassland and 15 MgC ha−1 for cropland).Differences between the final harmonized AGBC map and GlobBiomass AGBC. GlobBiomass AGB was aggregated to a 300 m spatial resolution and converted to C density prior to comparison. Negative values indicate areas where the new map reports lower values than GlobBiomass while positive value denote higher estimates.Larger deviations from GlobBiomass were also present in areas of both dryland Africa and the Arctic tundra biome, where we used independent layers to estimate woody biomass. In African drylands, GlobBiomass likely underestimates woody biomass by adopting the conservative FAO definition (DBH > 10 cm), which implicitly omits the relatively small trees and shrubs that are common to the region. The Bouvet map of Africa that we used to supplement these estimates is not bound by this constraint, was developed from region-specific data, and predicts substantially higher AGB density throughout much of its extent with comparatively high accuracy (RMSE = 17.1 Mg ha−1)35.GlobBiomass also included sporadic biomass estimates throughout much of the Arctic tundra biome. Trees are generally scarce throughout this biome, which is instead dominated by dwarf shrubs and herbaceous forbs and graminoids, so given GlobBiomass’s adherence to FAO guidelines, its predictions here may be spurious. We thus prioritized the estimates of the independent model developed specifically to collectively predict biomass of both woody and herbaceous tundra vegetation. These estimates were generally higher than GlobBiomass but agreed well with independent validation data from North America (RMSE = 2.9 Mg ha−1)18.While far from a perfect comparison, the only other map to comprehensively report global biomass carbon density for all landcover types is the IPCC Tier-1 map for the year 2000 by Ruesch and Gibbs28. As previously described, this map was produced using an entirely different method (“stratify and multiply”) and distinct data sources23 and represents an earlier epoch. However, the map is widely used for myriad applications, and it may thus be informative to assess notable differences between it and our new products.Ruesch and Gibbs28 report total living C stocks of 345 petagrams (PgC) in AGBC and 133 PgC in BGBC for a total of 478 PgC, globally. Our estimates are lower at 287 PgC and 122 PgC in global AGBC and BGBC, respectively, for a total of 409 PgC in living global vegetation biomass. Herbaceous biomass in our maps comprised 9.1 and 28.3 PgC of total AGBC and BGBC, respectively. Half of all herbaceous AGBC (4.5 PgC) and roughly 6% of all herbaceous BGBC (1.7 PgC) was found in croplands. Moreover, we mapped 22.3 and 6.1 PgC, respectively, in the AGB and BGB of trees located within the cropland extent. These trees constituted roughly 7% of all global biomass C and are likely overlooked by both the Ruesch and Gibbs map28 and by remotely sensed forest C maps that are masked to forested areas. Zomer et al.17 first highlighted this potential discrepancy in the Ruesch and Gibbs map28 when they produced a remarkably similar estimate of 34.2 Pg of overlooked C in cropland trees using Tier-1 defaults. However, their estimates were assumed to be in addition to the 474 PgC originally mapped by Ruesch and Gibbs28. Here, we suggest that the 28.4 PgC we mapped in cropland trees is already factored into our 409 PgC total.Our AGBC product predicts substantially less biomass C than Ruesch and Gibbs28 throughout most of the pantropical region and, to a lesser extent, southern temperate forests (Fig. 8a). This pattern has been noted by others comparing the Ruesch and Gibbs map28 to other satellite-based biomass maps73 and may suggest that the IPCC default values used to create it23 are spatially biased. In addition, well-defined areas of high disagreement emerge in Africa that directly correspond with the FAO boundaries of the “tropical moist deciduous forest” ecofloristic zone and suggest that this area, in particular, may merit critical review. Moreover, the opposite pattern is observed in this same ecofloristic zone throughout South America. Our map also predicts greater AGBC throughout much of the boreal forest as well as in African shrublands and the steppes of South America.Differences between the 2010 harmonized global maps of above and belowground biomass carbon density and those of the IPCC Tier-1 product by Ruesch and Gibbs for 2000. Comparisons of AGBC (a) and BGBC (b) maps are shown separately. Negative values indicate that the circa 2010 estimates are comparatively lower while positive values indicate higher estimates.We observed similar, though less pronounced discrepancies, when comparing BGBC maps (Fig. 8b). Notably, our map predicts substantially more BGBC throughout the tundra biome – a previously underappreciated C stock that has recently risen to prominance74 – the boreal forest, African shrublands and most of South America and Australia. However, we predict less BGBC in nearly all rainforests (Temperate and Tropical). These differences and their distinct spatial patterns correspond with the vegetation strata used to make the IPCC Tier-1 map28 and suggest that the accuracy of the “stratify and multiply” method depends heavily upon the quality of the referenced and spatial data considered. Inaccuracies in these data may, in turn, lead to false geographies. Integrating, continuous spatial estimates that better capture local and regional variation, as we have done, may thus greatly improve our understanding of global carbon geographies and their role in the earth system.The error and variance between our woody biomass estimates – when aggregated to the country level – and comparable totals reported in the FRA were less for comparisons made against FRA estimates generated using higher tier IPCC methodologies than for those based on Tier-1 approaches (Fig. 9). Across the board for AGBC, BGBC, and total C comparisons, the relative RMSE (RMSECV) of our estimates, when compared to estimates generated using high tier methods, was roughly half of that obtained from comparisons with Tier-1 estimates (Table 8). Likewise, the coefficient of determination (R2) was greatest for comparisons with Tier-3 estimates. For each pool-specific comparison (AGBC, BGBC, and total C), the slopes of the relationships between Tier-1, 2, and 3 estimates were neither significantly different from a 1:1 relationship nor from one another (p > 0.05; ANCOVA). Combined, these results suggest that our maps lead to C stock estimates congruent with those attained from independent, higher-tier reporting methodologies.Comparison of woody biomass density estimates to corresponding estimates of the FAO’s FRA and the USFS’s FIA. National woody AGBC totals derived from the woody components of our harmonized maps are compared to national totals reported in the 2015 FRA62 (a) in relation to the IPCC inventory methodology used by each country. Likewise, we derived woody AGBC totals for US states and compared them to the corresponding totals reported by the 2014 FIA75 (b), a Tier-3 inventory. We also show the additional effect of considering non-woody C – as is reported in our harmonized maps – in light green. Similar comparisons were made between our woody BGBC estimates and the corresponding estimates of both the FRA (c) and FIA (d). We further summed our woody AGBC and BGBC estimates and compared them to the total woody C stocks reported by both the FRA (e) and FIA (f).To explore this association at a finer regional scale, we also compared our woody C estimates to the United States Forest Service’s Forest Inventory Analysis75 (FIA) and found similarly strong congruence for AGBC and Total C stocks but subtle overestimates for BGBC (Fig. 9). The FIA is a Tier-3 inventory of woody forest biomass C stocks that is based on extensive and statistically rigorous field sampling and subsequent upscaling, We used data available at the state level for the year 2014 – again, the only year in which we could obtain data partitioned by AGBC and BGBC. Like our FRA comparison, we found a tight relationship between our woody AGBC totals and those reported by the FIA (Fig. 9b; RMSECV = 25.7%, R2 = 0.960, slope = 1.10, n = 48). Our woody BGBC estimates, though, were systematically greater than those reported by the FIA (Fig. 9d; RMSECV = 86.4%, R2 = 0.95, slope = 1.51, n = 48). This trend has been noted by others27 and suggests that the global model that we used to estimate woody BGBC may not be appropriate for some finer scale applications as is foretold by the elevated uncertainty reported in our corresponding uncertainty layer (Fig. 5b). Our total woody C (AGBC + BGBC) estimates (Fig. 9f), however, agreed well with the FIA (RMSECV = 34.1%, R2 = 0.961, slope = 1.17, n = 48) and thus reflect the outsized contribution of AGBC to the total woody C stock. When the contribution of herbaceous C stocks is further added to these comparisons, our stock estimates intuitively increase in rough proportion to a state’s proportional extent of herbaceous cover. The effect of this addition is particularly pronounced for BGBC estimates due to the large root-to-shoot ratios of grassland vegetation.The relative congruence of our results with higher-tier stock estimates suggests that our maps could be used to facilitate broader adoption of higher-tier methods among countries currently lacking the requisite data and those seeking to better account for C in non-woody biomass. This congruence spans a comprehensive range of biophysical conditions and spatial scales ranging from small states to large nations. Moreover, a recent study suggests that the fidelity of the underlying GlobBiomass AGB map may extend to even finer scales31. While our BGBC estimates may differ from some fine-scale estimates (Fig. 9d), their tight agreement with high tier BGBC totals at the national level (Fig. 9c) suggests that they may still be well suited for many national-scale C inventories – especially for countries lacking requisite high tier data. Use of our maps is unlikely to introduce error in excess of that currently implicit in Tier-1 estimates. Credence, though, should be given to the associated uncertainty estimates. To facilitate wider adoption of higher-tier methodologies, our maps could be used to derive new, region-specific default values for use in Tier-2 frameworks76 or to either represent or calibrate 2010 baseline conditions in Tier-3 frameworks. In so doing, inventories and studies alike could more accurately account for the nuanced global geographies of biomass C.These maps are intended for global applications in which continuous spatial estimates of live AGBC and/or BGBC density are needed that span a broad range of vegetation types and/or require estimates circa 2010. They are loosely based upon and share the spatial resolution of the ESA CCI Landcover 2010 map37, which can be used to extract landcover specific C totals. However, our products notably do not account for C stored in non-living C pools like litter or coarse woody debris, nor soil organic matter, though these both represent large, additional ecosystem C stocks77,78,79. Our maps are explicitly intended for global scale applications seeking to consider C in the collective living biomass of multiple vegetation types. For global scale applications focused exclusively on the C stocks of a single vegetation type, we strongly encourage users to instead use the respective input map or model referenced in Table 1 to avoid potential errors that may have been introduced by our harmonization procedure. For AGB applications over smaller extents, users should further consider whether locally specific products are available. If such maps are not available and our maps are considered instead, credence should be given to their pixel-level uncertainty estimates. As mentioned above, the biomass of shrublands was only explicitly accounted for in Africa and the Arctic tundra, since neither broad-scale maps nor models generalizable to other areas were available in the existing literature. As such, we caution against the use of our maps outside of these areas when shrubland biomass is of particular interest or importance. Moreover, in contrast to the estimates for all other vegetation types considered, which we upscaled to a 300 m resolution, cropland C estimates were largely based on relatively coarse 8 km resolution data that were downscaled using bilinear resampling to achieve a 300 m spatial resolution. As such, these estimates may not adequately capture the underlying finer-scale spatial variation and should be interpreted with that in mind. Likewise, we reiterate that some BGBC estimates may differ from locally derived Tier-3 estimates, and attention should thus be given to our reported pixel-level uncertainty for all applications. Finally, our maps should not be used in comparison with the IPCC Tier-1 map of Ruesch and Gibbs (2008) to detect biomass change between the two study periods due to significant methodological differences between these products.Cropland biomass maps were created in the R statistical computing environment80. All other coding was done in Google Earth Engine81 (GEE), wherein our workflow consisted of 18 interconnected scripts. All code can be found on GitHub (https://github.com/sethspawn/globalBiomassC) and permanently archived by Zenodo82.Houghton, R. A., Hall, F. & Goetz, S. J. Importance of biomass in the global carbon cycle. J. Geophys. Res. Biogeosciences 114 (2009).Huntzinger, D. N. et al. The North American Carbon Program Multi-Scale Synthesis and Terrestrial Model Intercomparison Project – Part 1: Overview and experimental design. Geosci. Model Dev 6, 2121–2133 (2013).Article ADS Google Scholar Schwalm, C. R. et al. Toward “optimal” integration of terrestrial biosphere models. Geophys. Res. Lett. 42, 4418–4428 (2015).Article ADS Google Scholar Li, W. et al. Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations. Biogeosciences 14, 5053–5067 (2017).Article Google Scholar Spawn, S. A., Lark, T. J. & Gibbs, H. K. Carbon emissions from cropland expansion in the United States. Environ. Res. Lett. 14, 045009 (2019).Article CAS ADS Google Scholar Harris, N. L. et al. Baseline Map of Carbon Emissions from Deforestation in Tropical Regions. Science 336, 1573–1576 (2012).Article CAS PubMed ADS Google Scholar Baccini, A. et al. Tropical forests are a net carbon source based on aboveground measurements of gain and loss. Science 358, 230–234 (2017).Article MathSciNet CAS PubMed MATH ADS Google Scholar Strassburg, B. B. N. et al. Global congruence of carbon storage and biodiversity in terrestrial ecosystems. Conserv. Lett 3, 98–105 (2010).Article Google Scholar West, P. C. et al. Trading carbon for food: Global comparison of carbon stocks vs. crop yields on agricultural land. Proc. Natl. Acad. Sci. 107, 19645–19648 (2010).Article CAS PubMed ADS PubMed Central Google Scholar Carvalhais, N. et al. Global covariation of carbon turnover times with climate in terrestrial ecosystems. Nature 514, 213–217 (2014).Article CAS PubMed ADS Google Scholar Brandão, A. et al. Estimating the Potential for Conservation and Farming in the Amazon and Cerrado under Four Policy Scenarios. Sustainability 12, 1277 (2020).Article Google Scholar Gibbs, H. K., Brown, S., Niles, J. O. & Foley, J. A. Monitoring and estimating tropical forest carbon stocks: making REDD a reality. Environ. Res. Lett. 2, 045023 (2007).Article ADS CAS Google Scholar Fargione, J. E. et al. Natural climate solutions for the United States. Sci. Adv. 4, eaat1869 (2018).Article PubMed PubMed Central ADS Google Scholar Griscom, B. W. et al. Natural climate solutions. Proc. Natl. Acad. Sci. 114, 11645–11650 (2017).Article CAS PubMed ADS PubMed Central Google Scholar Goetz, S. J. et al. Mapping and monitoring carbon stocks with satellite observations: a comparison of methods. Carbon Balance Manag 4, 2 (2009).Article PubMed PubMed Central CAS Google Scholar Xiao, J. et al. Remote sensing of the terrestrial carbon cycle: A review of advances over 50 years. Remote Sens. Environ. 233, 111383 (2019).Article ADS Google Scholar Zomer, R. J. et al. Global Tree Cover and Biomass Carbon on Agricultural Land: The contribution of agroforestry to global and national carbon budgets. Sci. Rep 6, 29987 (2016).Article CAS PubMed PubMed Central ADS Google Scholar Berner, L. T., Jantz, P., Tape, K. D. & Goetz, S. J. Tundra plant above-ground biomass and shrub dominance mapped across the North Slope of Alaska. Environ. Res. Lett. 13, 035002 (2018).Article ADS Google Scholar Xia, J. et al. Spatio-Temporal Patterns and Climate Variables Controlling of Biomass Carbon Stock of Global Grassland Ecosystems from 1982 to 2006. Remote Sens 6, 1783–1802 (2014).Article ADS Google Scholar Monfreda, C., Ramankutty, N. & Foley, J. A. Farming the planet: 2. Geographic distribution of crop areas, yields, physiological types, and net primary production in the year 2000. Glob. Biogeochem. Cycles 22, GB1022 (2008).Article ADS CAS Google Scholar Wolf, J. et al. Biogenic carbon fluxes from global agricultural production and consumption. Glob. Biogeochem. Cycles 29, 1617–1639 (2015).Article CAS ADS Google Scholar Mokany, K., Raison, R. J. & Prokushkin, A. S. Critical analysis of root: shoot ratios in terrestrial biomes. Glob. Change Biol. 12, 84–96 (2006).Article ADS Google Scholar IPCC 2006. 2006 IPCC Guidelines for National Greenhouse Gas Inventories. vol. 4 (IPCC National Greenhouse Gas Inventories Programme, 2006).IPCC 2019. 2019 Refinement to the 2006 IPCC Guidlines for National Greenhouse Gas Inventories. vol. 4 (IPCC National Greenhouse Gas Inventories Programme, 2019).Reich, P. B. et al. Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots. Proc. Natl. Acad. Sci. 111, 13721–13726 (2014).Article CAS PubMed ADS PubMed Central Google Scholar Wang, P. et al. Belowground plant biomass allocation in tundra ecosystems and its relationship with temperature. Environ. Res. Lett. 11, 055003 (2016).Article ADS CAS Google Scholar Russell, M. B., Domke, G. M., Woodall, C. W. & D’Amato, A. W. Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States. Carbon Balance Manag 10, 20 (2015).Article PubMed PubMed Central CAS Google Scholar Ruesch, A. & Gibbs, H. New IPCC Tier-1 Global Biomass Carbon Map for the Year 2000. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, http://cdiac.ess-dive.lbl.gov (2008).Schimel, D. et al. Observing terrestrial ecosystems and the carbon cycle from space. Glob. Change Biol. 21, 1762–1776 (2015).Article ADS Google Scholar Santoro, M. et al. GlobBiomass - global datasets of forest biomass. PANGAEA https://doi.org/10.1594/PANGAEA.894711 (2018).Huang, W. et al. High-Resolution Mapping of Aboveground Biomass for Forest Carbon Monitoring System in the 3 Tri-State Region of Maryland, Pennsylvania and Delaware, USA. Environ. Res. Lett. 14, 095002 (2019).Article ADS Google Scholar Food and Agricultural Organization. FRA 2015 Terms and Definitions. (Food and Agricultural Organization of the United Nations, 2012).Quegan, S. et al. DUE GlobBiomass: D6 - Global Biomass Map Algorithm Theoretical Basis Document. GlobBiomass, http://globbiomass.org/wp-content/uploads/DOC/Deliverables/D6_D7/GlobBiomass_D6_7_Global_ATBD_v2.pdf (2017).Hansen, M. C. et al. High-Resolution Global Maps of 21st-Century Forest Cover Change. Science 342, 850–853 (2013).Article CAS PubMed ADS Google Scholar Bouvet, A. et al. An above-ground biomass map of African savannahs and woodlands at 25 m resolution derived from ALOS PALSAR. Remote Sens. Environ. 206, 156–173 (2018).Article ADS Google Scholar Le Toan, T., Beaudoin, A., Riom, J. & Guyon, D. Relating forest biomass to SAR data. IEEE Trans. Geosci. Remote Sens 30, 403–411 (1992).Article ADS Google Scholar European Space Agency. 300 m Annual global land cover time series from 1992 to 2015. European Space Agency - Climate Change Initiative, http://maps.elie.ucl.ac.be/CCI/viewer/download.php (2017).Bartholomé, E. & Belward, A. S. GLC2000: a new approach to global land cover mapping from Earth observation data. Int. J. Remote Sens. 26, 1959–1977 (2005).Article ADS Google Scholar Avitabile, V. et al. An integrated pan-tropical biomass map using multiple reference datasets. Glob. Change Biol. 22, 1406–1420 (2016).Article ADS Google Scholar Englund, O. et al. A new high-resolution nationwide aboveground carbon map for Brazil. Geo Geogr. Environ. 4, e00045 (2017).Article Google Scholar Scholze, M., Buchwitz, M., Dorigo, W., Guanter, L. & Quegan, S. Reviews and syntheses: Systematic Earth observations for use in terrestrial carbon cycle data assimilation systems. Biogeosciences 14, 3401–3429 (2017).Article CAS ADS Google Scholar Martin, A. R., Doraisami, M. & Thomas, S. C. Global patterns in wood carbon concentration across the world’s trees and forests. Nat. Geosci. 11, 915 (2018).Article CAS ADS Google Scholar Kottek, M., Grieser, J., Beck, C., Rudolf, B. & Rubel, F. World Map of the Köppen-Geiger climate classification updated. Meteorol. Z. 15, 259–263 (2006).Article Google Scholar Olofsson, P. et al. Good practices for estimating area and assessing accuracy of land change. Remote Sens. Environ. 148, 42–57 (2014).Article ADS Google Scholar Berner, L. T., Jantz, P., Tape, K. D. & Goetz, S. J. ABoVE: Gridded 30-m Aboveground Biomass, Shrub Dominance, North Slope, AK, 2007–2016. Oak Ridge National Laboratory Distributed Active Archive Center https://doi.org/10.3334/ORNLDAAC/1565 (2018).Vermote, E. F. & Wolfe, R. MYD09GQ MODIS/Aqua Surface Reflectance Daily L2G Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MYD09GQ.006 (2015).Vermote, E. F. & Wolfe, R. MOD09GQ MODIS/Terra Surface Reflectance Daily L2G Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MOD09GQ.006 (2015).Steven, M. D., Malthus, T. J., Baret, F., Xu, H. & Chopping, M. J. Intercalibration of vegetation indices from different sensor systems. Remote Sens. Environ. 88, 412–422 (2003).Article ADS Google Scholar Adler, P. B. et al. Productivity Is a Poor Predictor of Plant Species Richness. Science 333, 1750–1753 (2011).Article CAS PubMed ADS Google Scholar Didan, K. MYD13Q1 MODIS/Aqua Vegetation Indices 16-Day L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MYD13Q1.006 (2015).Didan, K. MOD13Q1 MODIS/Terra Vegetation Indices 16-Day L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center https://doi.org/10.5067/MODIS/MOD13Q1.006 (2015).Fensholt, R. & Proud, S. R. Evaluation of Earth Observation based global long term vegetation trends — Comparing GIMMS and MODIS global NDVI time series. Remote Sens. Environ. 119, 131–147 (2012).Article ADS Google Scholar Li, Z. et al. Comparing cropland net primary production estimates from inventory, a satellite-based model, and a process-based model in the Midwest of the United States. Ecol. Model. 277, 1–12 (2014).Article Google Scholar Turner, D. P. et al. Evaluation of MODIS NPP and GPP products across multiple biomes. Remote Sens. Environ. 102, 282–292 (2006).Article ADS Google Scholar Ramankutty, N., Evan, A. T., Monfreda, C. & Foley, J. A. Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000. Glob. Biogeochem. Cycles 22, GB1003 (2008).Grassini, P., Eskridge, K. M. & Cassman, K. G. Distinguishing between yield advances and yield plateaus in historical crop production trends. Nat. Commun. 4, 2918 (2013).Article PubMed ADS CAS Google Scholar Gray, J. M. et al. Direct human influence on atmospheric CO2 seasonality from increased cropland productivity. Nature 515, 398–401 (2014).Article CAS PubMed ADS Google Scholar Running, S. W., Mu, Q. & Zhao, M. MOD17A3H MODIS/Terra Net Primary Production Yearly L4 Global 1 km SIN Grid V055. NASA EOSDIS Land Processes Distributed Active Archive Center, https://lpdaac.usgs.gov/products/mod17a3v055/ (2015).Fick, S. & Hijmans, R. WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas. Int. J. Climatol. 37, 4302–4315 (2017).Article Google Scholar Potapov, P. et al. The last frontiers of wilderness: Tracking loss of intact forest landscapes from 2000 to 2013. Sci. Adv. 3, e1600821 (2017).Article PubMed PubMed Central ADS Google Scholar Harris, N. L., Goldman, E. D. & Gibbes, S. Spatial Database of Planted Trees (SDPT Version 1.0). World Resources Institute, https://www.wri.org/publication/planted-trees (2019).Food and Agricultural Organization. Global Forest Resources Assessment 2015: Desk Reference. (Food and Agricultural Organization of the United Nations, 2015).Dimiceli, C. et al. MOD44B MODIS/Terra Vegetation Continuous Fields Yearly L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MOD44B.006 (2015).Sexton, J. O. et al. Global, 30-m resolution continuous fields of tree cover: Landsat-based rescaling of MODIS vegetation continuous fields with lidar-based estimates of error. Int. J. Digit. Earth 6, 427–448 (2013).Article ADS Google Scholar Dinerstein, E. et al. An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm. BioScience 67, 534–545 (2017).Article PubMed PubMed Central Google Scholar Spawn, S. A. & Gibbs, H. K. Global Aboveground and Belowground Biomass Carbon Density Maps for the Year 2010. Oak Ridge National Laboratory Distributed Active Archive Center, https://doi.org/10.3334/ORNLDAAC/1763 (2019).Spawn, S. A., Sullivan, C. C., Lark, T. J. & Gibbs, H. K. Harmonized global maps of above and belowground biomass carbon density in the year 2010. figshare https://doi.org/10.6084/m9.figshare.c.4561940 (2020).Gao, Q. et al. Climatic change controls productivity variation in global grasslands. Sci. Rep 6, 26958 (2016).Article CAS PubMed PubMed Central ADS Google Scholar de Jong, R., Verbesselt, J., Schaepman, M. E. & de Bruin, S. Trend changes in global greening and browning: contribution of short-term trends to longer-term change. Glob. Change Biol 18, 642–655 (2012).Article ADS Google Scholar Gonsamo, A., Chen, J. M. & Lombardozzi, D. Global vegetation productivity response to climatic oscillations during the satellite era. Glob. Change Biol. 22, 3414–3426 (2016).Article ADS Google Scholar Ray, D. K. et al. Climate change has likely already affected global food production. Plos One 14, e0217148 (2019).Article CAS PubMed PubMed Central Google Scholar Lobell, D. B., Schlenker, W. & Costa-Roberts, J. Climate Trends and Global Crop Production Since 1980. Science 333, 616–620 (2011).Article CAS PubMed ADS Google Scholar Hu, T. et al. Mapping Global Forest Aboveground Biomass with Spaceborne LiDAR, Optical Imagery, and Forest Inventory Data. Remote Sens 8, 565 (2016).Article ADS Google Scholar Iversen, C. M. et al. The unseen iceberg: plant roots in arctic tundra. New Phytol. 205, 34–58 (2015).Article PubMed Google Scholar USDA Forest Service. Forest Inventory and Analysis National Program: Standard Tables of Forest Caron Stock Estimates by State. Forest Inventory and Analysis National Program, https://www.fia.fs.fed.us/forestcarbon/index.php (2014).Langner, A., Achard, F. & Grassi, G. Can recent pan-tropical biomass maps be used to derive alternative Tier 1 values for reporting REDD + activities under UNFCCC? Environ. Res. Lett. 9, 124008 (2014).Article ADS Google Scholar Jobbágy, E. G. & Jackson, R. B. The Vertical Distribution of Soil Organic Carbon and Its Relation to Climate and Vegetation. Ecol. Appl. 10, 423–436 (2000).Article Google Scholar Scharlemann, J. P., Tanner, E. V., Hiederer, R. & Kapos, V. Global soil carbon: understanding and managing the largest terrestrial carbon pool. Carbon Manag 5, 81–91 (2014).Article CAS Google Scholar Domke, G. M., Woodall, C. W., Walters, B. F. & Smith, J. E. From Models to Measurements: Comparing Downed Dead Wood Carbon Stock Estimates in the U.S. Forest Inventory. Plos One 8, e59949 (2013).Article CAS PubMed PubMed Central ADS Google Scholar R Core Team. R: A Language and Environment for Statistical Computing, https://www.R-project.org/ (2017).Gorelick, N. et al. Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sens. Environ. 202, 18–27 (2017).Article ADS Google Scholar Spawn, S. A. sethspawn/globalBiomassC. Zenodo https://doi.org/10.5281/zenodo.3647567 (2020).Olson, D. M. et al. Terrestrial Ecoregions of the World: A New Map of Life on EarthA new global map of terrestrial ecoregions provides an innovative tool for conserving biodiversity. BioScience 51, 933–938 (2001).European Space Agency. Land Cover CCI Product User Guide Version 2, D3.4-PUG, v2.5. European Space Agency - Climate Change Initiative, http://maps.elie.ucl.ac.be/CCI/viewer/download/ESACCI-LC-PUG-v2.5.pdf (2016).Friedl, M. A. & Sulla-Menashe, D. MCD12Q1 MODIS/Terra + Aqua Land Cover Type Yearly L3 Global 500 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MCD12Q1.006 (2019).Jing, Q., Bélanger, G., Baron, V. & Bonesmo, H. Modeling the Biomass and Harvest Index Dynamics of Timothy. Agron. J. 103, 1397–1404 (2011).Article Google Scholar West, T. O. et al. Cropland carbon fluxes in the United States: increasing geospatial resolution of inventory-based carbon accounting. Ecol. Appl. 20, 1074–1086 (2010).Article PubMed Google Scholar Unkovich, M., Baldock, J. & Forbes, M. Variability in harvest index of grain crops and potential significance for carbon accounting: examples from Australian agriculture. Adv. Agron 105, 173–219 (2010).Article Google Scholar Hay, R. K. M. Harvest index: a review of its use in plant breeding and crop physiology. Ann. Appl. Biol. 126, 197–216 (1995).Article Google Scholar Larcher, W. Physiological Plant Ecology: Ecophysiology and Stress Physiology of Functional Groups. (Springer-Verlag, 2003).Hakala, K., Keskitalo, M. & Eriksson, C. Nutrient uptake and biomass accumulation for eleven different field crops. Agric. Food Sci 18, 366–387 (2009).Article CAS Google Scholar Bolinder, M. A., Janzen, H. H., Gregorich, E. G., Angers, D. A. & VandenBygaart, A. J. An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada. Agric. Ecosyst. Environ 118, 29–42 (2007).Article Google Scholar Mackenzie, B. A. & Van Fossen, L. Managing Dry Grain In Storage. In Agricultural Engineers’ Digest vol. 20 (Purdue University Cooperative Extension Service, 1995).Goodwin, M. Crop Profile for Dry Bean in Canada. Agriculture and Agri-Food Canada, http://publications.gc.ca/collections/collection_2009/agr/A118-10-4-2005E.pdf (2005).Schulte auf’m Erley, G., Kaul, H.-P., Kruse, M. & Aufhammer, W. Yield and nitrogen utilization efficiency of the pseudocereals amaranth, quinoa, and buckwheat under differing nitrogen fertilization. Eur. J. Agron. 22, 95–100 (2005).Article CAS Google Scholar Bjorkman, T. Northeast Buckwheat Growers Newsletter No. 19. Cornell University NYSAES, http://www.hort.cornell.edu/bjorkman/lab/buck/NL/june05.php (2005).Kyle, G. P. et al. GCAM 3.0 Agriculture and Land Use: Data Sources and Methods, https://doi.org/10.2172/1036082 (2011).Bastin, S. & Henken, K. Water Content of Fruits and Vegetables. University of Kentucky Cooperative Extension Service, https://www.academia.edu/5729963/Water_Content_of_Fruits_and_Vegetables (1997).Smil, V. Crop Residues: Agriculture’s Largest HarvestCrop residues incorporate more than half of the world’s agricultural phytomass. BioScience 49, 299–308 (1999).Article Google Scholar Squire, G. R. The physiology of tropical crop production. (C.A.B. International, 1990).Williams, J. R. et al. EPIC users guide v. 0509. Texas A & M University Blackland Research and Extension Center, http://epicapex.tamu.edu/files/2013/02/epic0509usermanualupdated.pdf (2006).Okeke, J. E. Cassava varietal improvement for processing and utilization in livestock feeds. In Cassava as Livestock Feed in Africa (International Institute of Tropical Agriculture, 1992).Pongsawatmanit, R., Thanasukarn, P. & Ikeda, S. Effect of Sucrose on RVA Viscosity Parameters, Water Activity and Freezable Water Fraction of Cassava Starch Suspensions. ScienceAsia 28, 129–134 (2002).Article CAS Google Scholar Gigou, J. et al. Fonio Millet (Digitaria Exilis) Response to N, P and K Fertilizers Under Varying Climatic Conditions in West. AFRICA. Exp. Agric 45, 401–415 (2009).Article Google Scholar Food and Agricultural Organization. FAOSTAT 2001: FAO statistical databasees. FAOSTAT, http://www.fao.org/faostat/en/#data (2006).Bolinder, M. A., Angers, D. A., Bélanger, G., Michaud, R. & Laverdière, M. R. Root biomass and shoot to root ratios of perennial forage crops in eastern Canada. Can. J. Plant Sci. 82, 731–737 (2002).Article Google Scholar Deferne, J. & Pate, D. W. Hemp seed oil: A source of valuable essential fatty acids. J. Int. Hemp Assoc 3, 4–7 (1996). Google Scholar Islam, Md. R. et al. Study of Harvest Index and Genetic Variability in White Jute (Corchorus capsularis) Germplasm. J. Biol. Sci. 2, 358–360 (2002).Article Google Scholar Ahad, A. & Debnath, C. N. Shoot Root Ratio of Jute Varieties and the Nature of Association Between Root Characteristics and the Yield of Dry Matter and Fiber. Bangladesh J. Agric. Res 13, 17–22 (1988). Google Scholar Mondal, S. S., Ghosh, A. & Debabrata, A. Effect of seeding time of linseed (Linum usitatissimum) in rice (Oryza sativa)-based paira cropping system under rainfed lowland condition. Indian J. Agric. Sci 75, 134–137 (2005). Google Scholar Ayaz, S., Moot, D. J., Mckenzie, B. A., Hill, G. D. & Mcneil, D. L. The Use of a Principal Axis Model to Examine Individual Plant Harvest Index in Four Grain Legumes. Ann. Bot. 94, 385–392 (2004).Article CAS PubMed PubMed Central Google Scholar Goudriaan, J. & Van Laar, H. H. Development and growth. In Modelling Potential Crop Growth Processes: Textbook with Exercises (eds. Goudriaan, J. & Van Laar, H. H.) 69–94 (Springer Netherlands, 1994).National Research Council. Nutrient Requirements of Nonhuman Primates: Second Revised Edition. (The National Academies Press, 2003).Roth, C. M., Shroyer, J. P. & Paulsen, G. M. Allelopathy of Sorghum on Wheat under Several Tillage Systems. Agron. J. 92, 855–860 (2000).Article Google Scholar Heidari Zooleh, H. et al. Effect of alternate irrigation on root-divided Foxtail Millet (Setaria italica). Aust. J. Crop Sci 5, 205–2013 (2011). Google Scholar Brück, H., Sattelmacher, B. & Payne, W. A. Varietal differences in shoot and rooting parameters of pearl millet on sandy soils in Niger. Plant Soil 251, 175–185 (2003).Article Google Scholar Oelke, E. A., Putnam, D. H., Teynor, T. M. & Oplinger, E. S. Quinoa. In Alternative Field Crops Manual (University of Wisconsin-Extension, Cooperative Extension, 1992).Robertson, M. J., Silim, S., Chauhan, Y. S. & Ranganathan, R. Predicting growth and development of pigeonpea: biomass accumulation and partitioning. Field Crops Res 70, 89–100 (2001).Article Google Scholar Armstrong, E. Desiccation & harvest of field peas. In Pulse management in Southern New South Wales (State of New South Wales Agriculture, 1999).Fischer, R. A. (Tony) & Edmeades, G. O. Breeding and Cereal Yield Progress. Crop Sci. 50, S-85–S-98 (2010).Article Google Scholar Atlin, G. N. et al. Developing rice cultivars for high-fertility upland systems in the Asian tropics. Field Crops Res 97, 43–52 (2006).Article Google Scholar Bueno, C. S. & Lafarge, T. Higher crop performance of rice hybrids than of elite inbreds in the tropics: 1. Hybrids accumulate more biomass during each phenological phase. Field Crops Res 112, 229–237 (2009).Article Google Scholar Yang, J. & Zhang, J. Crop management techniques to enhance harvest index in rice. J. Exp. Bot 61, 3177–3189 (2010).Article CAS PubMed Google Scholar Ziska, L. H., Namuco, O., Moya, T. & Quilang, J. Growth and Yield Response of Field-Grown Tropical Rice to Increasing Carbon Dioxide and Air Temperature. Agron. J. 89, 45–53 (1997).Article Google Scholar Mwaja, V. N., Masiunas, J. B. & Weston, L. A. Effects of fertility on biomass, phytotoxicity, and allelochemical content of cereal rye. J. Chem. Ecol. 21, 81–96 (1995).Article CAS PubMed Google Scholar Bruinsma, J. & Schuurman, J. J. The effect of spraying with DNOC (4,6-dinitro-o-cresol) on the growth of the roots and shoots of winter rye plants. Plant Soil 24, 309–316 (1966).Article CAS Google Scholar Yau, S. K., Sidahmed, M. & Haidar, M. Conservation versus Conventional Tillage on Performance of Three Different Crops. Agron. J. 102, 269–276 (2010).Article Google Scholar Hojati, M., Modarres-Sanavy, S. A. M., Karimi, M. & Ghanati, F. Responses of growth and antioxidant systems in Carthamustinctorius L. under water deficit stress. Acta Physiol. Plant. 33, 105–112 (2011).Article Google Scholar Oelke, E. A. et al. Safflower. In Alternative Field Crops Manual (University of Wisconsin-Extension, Cooperative Extension, 1992).Perez, R. Chapter 3: Sugar cane. In Feeding pigs in the tropics (Food and Agricultural Organization of the United Nations, 1997).Van Dillewijn, C. Botany of Sugarcane. (Chronica Botanica Co, 1952).Pate, F. M., Alvarez, J., Phillips, J. D. & Eiland, B. R. Sugarcane as a Cattle Feed: Production and Utilization. (University of Florida Extension Institute of Food and Agricultural Sciences, 2002).Download referencesWe gratefully acknowledge all the data producers, without whom this work would not be possible. We especially thank Maurizio Santoro et al., Alexandre Bouvet et al., Jiangzhou Xia et al., Logan T. Berner et al., Chad Monfreda et al., and Julie Wolf et al. whose AGB estimates comprise the core of our harmonized products and, in many cases, whose feedback greatly improved the quality of their inclusion. We are also grateful to the thoughtful feedback of three anonymous reviewers whose suggestions greatly improved the quality of our products and the clarity of our manuscript. Funding for this project was generously provided by the David and Lucile Packard Foundation and the National Wildlife Federation.Department of Geography, University of Wisconsin-Madison, Madison, WI, USASeth A. Spawn, Clare C. Sullivan & Holly K. GibbsCenter for Sustainability and the Global Environment (SAGE), Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, WI, USASeth A. Spawn, Clare C. Sullivan, Tyler J. Lark & Holly K. GibbsYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarS.A.S. designed the harmonization procedure, compiled and standardized individual biomass layers, conducted all mapping, and led manuscript development. C.C.S., T.J.L. and H.K.G. assisted with conceptualization, and manuscript development.Correspondence to Seth A. Spawn.The authors declare no competing interests.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.The Creative Commons Public Domain Dedication waiver http://creativecommons.org/publicdomain/zero/1.0/ applies to the metadata files associated with this article.Reprints and PermissionsSpawn, S.A., Sullivan, C.C., Lark, T.J. et al. Harmonized global maps of above and belowground biomass carbon density in the year 2010. Sci Data 7, 112 (2020). https://doi.org/10.1038/s41597-020-0444-4Download citationReceived: 03 July 2019Accepted: 14 February 2020Published: 06 April 2020DOI: https://doi.org/10.1038/s41597-020-0444-4Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative Nature Water (2023)Nature Plants (2023)Nature Communications (2023)Scientific Data (2023)Nature Communications (2023)Advertisement Scientific Data (Sci Data) ISSN 2052-4463 (online) © 2023 Springer Nature LimitedSign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily. January 22 - July 26, 2023JPEGOne of the wettest wet seasons in northern Australia transformed large areas of the country’s desert landscape over the course of many months in 2023. A string of major rainfall events that dropped 690 millimeters (27 inches) between October 2022 and April 2023 made it the sixth-wettest season on record since 1900–1901.This series of false-color images illustrates the rainfall’s months-long effects downstream in the Lake Eyre Basin. Water appears in shades of blue, vegetation is green, and bare land is brown. The images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite between January and July 2023.In the January 22 image (left), water was coursing through seasonally dry channels of the Georgina River and Eyre Creek following weeks of heavy rains in northern Queensland. By April 21 (middle), floodwaters had reached further downstream after another intense period of precipitation in March. This scene shows that water had filled in some of the north-northwest trending ridges that are part of a vast fossil landscape of wind-formed dunes, while vegetation had emerged in wet soil upstream. Then by July 26 (right), the riverbed had filled with even more vegetation.The Georgina River and Eyre Creek drain approximately 210,000 square kilometers (81,000 square miles), nearly the area of the United Kingdom. Visible in the lower part of the images, the lake gets refreshed about every three years; when it reaches especially high levels, it may take 18 months to 2 years to dry up. Two smaller neighboring lakes flood seasonally. These three lakes and surrounding floodplains support hundreds of thousands of waterbirds and are designated as an Important Bird Area.Seasonal flooding is a regular occurrence in these desert river systems. However, the events of the 2022-2023 rainy season stood out in several ways. They occurred while La Niña conditions were in place over the tropical Pacific Ocean. (The wettest seasons in northern Australia have all occurred during La Niña years, according to Australia’s Bureau of Meteorology.) In addition, major rains occurring in succession, as was the case with the January and March events, have the overall effect of prolonging floods. That’s because vegetation that grows after the first event slows down the pulse of water that comes through in the next rain event.The high water has affected both local communities and ecosystems. Floods have inundated cattle farms and isolated towns on temporary islands. At the same time, they are a natural feature of the “boom-and-bust” ecology of Channel Country, providing habitat and nutrients that support biodiversity.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerRepeated heavy rains in Australia set off waves of new growth across Channel Country.Image of the Day for August 7, 2023 Image of the Day Land Water View more Images of the Day: Floods The waves off the coast of Teahupo’o can heave a crushing amount of water toward the shore and onto unlucky surfers. Image of the Day Water Waves of heavy rainfall left towns and farmland under water in October 2022. Image of the Day Water Floods Acquired February 26, 2011, and February 5, 2011, these false-color images show the impact of heavy rains in marshy areas southeast of Georgetown, Guyana. Land Floods August 25, 2023JPEGSeptember 18, 2023JPEGAugust 25, 2023September 18, 2023August 25, 2023JPEGSeptember 18, 2023JPEGSeptember 18, 2023JPEGHeavy rain from a cyclone in the Mediterranean inundated cities along the northeastern coast of Libya in early September 2023, causing thousands of deaths. The port city of Derna (Darnah), home to about 90,000 people, was one of the worst hit by the storm and suffered extensive flooding and damage. On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered two dams along the wadi to collapse. The failure of the second dam, located just one kilometer inland of Derna, unleashed 3- to 7-meter-high floodwater that tore through the city. According to news reports, the flash floods destroyed roads and swept entire neighborhoods out to sea. The images above show the city before and after the storm. The image on the right, acquired by the Operational Land Imager-2 (OLI-2) on Landsat 9 on September 18, shows eroded banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image on the left, which shows the same area on August 25 and was acquired by Landsat 8. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that 3,100 buildings in Derna were damaged by rushing water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna. Tropical-like cyclones in the Mediterranean, or “medicanes,” develop only once or twice a year, according to NOAA, and typically form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africa’s recorded history. A recent assessment by scientists at World Weather Attribution estimated that precipitation received by the region was a one-in-300 to one-in-600-year event. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerFlash floods in the port city destroyed roads and swept neighborhoods out to sea.Image of the Day for September 21, 2023 Image of the Day Land Water Floods Human Presence View more Images of the Day:The melting of frozen rivers and snowpack, and the heavy rains of late spring and summer, can send rivers out of their banks.A Mediterranean cyclone contributed to deadly flooding along the country’s coastline. Image of the Day Land Water Floods Record rainfall inundated towns and farmland in the country’s Thessaly region. Image of the Day Water Floods Human Presence A stalled storm dropped three feet of rain over four days on the Thessaly region, triggering extensive flooding. Image of the Day Atmosphere Floods An isolated low-pressure system produced torrential downpours in Spain and carried Saharan dust along its path. Image of the Day Atmosphere Land Floods Human Presence July 2002 - June 2022JPEGThe deep-blue sea is turning a touch greener. While that may not seem as consequential as, say, record warm sea surface temperatures, the color of the ocean surface is indicative of the ecosystem that lies beneath. Communities of phytoplankton, microscopic photosynthesizing organisms, abound in near-surface waters and are foundational to the aquatic food web and carbon cycle. This shift in the water’s hue confirms a trend expected under climate change and signals changes to ecosystems within the global ocean, which covers 70 percent of Earth’s surface. Researchers led by B. B. Cael, a principal scientist at the U.K.’s National Oceanography Centre, revealed that 56 percent of the global sea surface has undergone a significant change in color in the past 20 years. After analyzing ocean color data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Aqua satellite, they found that much of the change stems from the ocean turning more green. The map above highlights the areas where ocean surface color changed between 2002 and 2022, with darker shades of green representing more-significant differences (higher signal-to-noise ratio). By extension, said Cael, “these are places we can detect a change in the ocean ecosystem in the last 20 years.” The study focused on tropical and subtropical regions, excluding higher latitudes, which are dark for part of the year, and coastal waters, where the data are naturally very noisy. The black dots on the map indicate the area, covering 12 percent of the ocean’s surface, where chlorophyll levels also changed over the study period. Chlorophyll has been the go-to measurement for remote sensing scientists to gauge phytoplankton abundance and productivity. However, those estimates use only a few colors in the visible light spectrum. The values shown in green are based on the whole gamut of colors and therefore capture more information about the ecosystem as a whole. A long time series from a single sensor is relatively rare in the remote sensing world. As the Aqua satellite was celebrating its 20th year in orbit in 2022—far exceeding its design life of 6 years—Cael wondered what long term trends could be discovered in the data. In particular, he was curious what might have been missed in all the ocean color information it had collected. “There’s more encoded in the data than we actually make use of,” he said. By going big with the data, the team discerned an ocean color trend that had been predicted by climate modeling, but one that was expected to take 30-40 years of data to detect using satellite-based chlorophyll estimates. That’s because the natural variability in chlorophyll is high relative to the climate change trend. The new method, incorporating all visible light, was robust enough to confirm the trend in 20 years. At this stage, it is difficult to say what exact ecological changes are responsible for the new hues. However, the authors posit, they could result from different assemblages of plankton, more detrital particles, or other organisms such as zooplankton. It is unlikely the color changes come from materials such as plastics or other pollutants, said Cael, since they are not widespread enough to register at large scales. “What we do know is that in the last 20 years, the ocean has become more stratified,” he said. Surface waters have absorbed excess heat from the warming climate, and as a result, they are less prone to mixing with deeper, more nutrient-rich layers. This scenario would favor plankton adapted to a nutrient-poor environment. The areas of ocean color change align well with where the sea has become more stratified, said Cael, but there is no such overlap with sea surface temperature changes. More insights into Earth’s aquatic ecosystems may soon be on the way. NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite, set to launch in 2024, will return observations in finer color resolution. The new data will enable researchers to infer more information about ocean ecology, such as the diversity of phytoplankton species and the rates of phytoplankton growth. NASA Earth Observatory image by Wanmei Liang, using data from Cael, B. B., et al. (2023). Story by Lindsey Doermann.Two decades of satellite measurements show that the sea surface is shading toward green.Image of the Day for October 2, 2023 Image of the Day Life Water View more Images of the Day:Datasets from the Sentinel-6 Michael Freilich satellite will build upon three decades of sea level measurements. Image of the Day Heat Water Remote Sensing Image of the Day Life Water Image of the Day Water The use of plastic on farms has become so common in recent decades that there there’s a term for it—plasticulture. Image of the Day Human Presence August 16, 2023JPEGThe Canary Islands were at the center of a mélange of natural events in summer 2023. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this assemblage of phenomena off the coast of Africa on August 16, 2023.In the center of the scene, smoke is seen rising from a wildfire burning on Tenerife in the Canary Islands. The blaze started amid hot and dry conditions on August 15 in forests surrounding the Teide Volcano. Authorities issued evacuation orders to five villages, and responders focused on containing the fire’s spread and protecting residential areas near the coast, according to news reports. Other fires have burned on the Canary Islands this summer, including on La Palma in July.To the west, a swirling cloud moves across the Atlantic. Cloud vortices appear routinely downwind of the Canary Islands—sometimes in great abundance—and are produced when the tall volcanic peaks disrupt the air flowing past them.Elsewhere in the atmosphere, dust from the Sahara Desert was lofted out over the ocean. The river of dust crossing the Atlantic was more pronounced in previous days, when it reached islands in the Caribbean. Traveling on the Saharan Air Layer, dust sometimes makes it even further west toward Central America and the U.S. states of Florida and Texas.To round out the list, the patch of bright blue off the Moroccan coast is most likely a bloom of phytoplankton. While the exact cause and composition of the bloom cannot be determined from this image, mineral-rich desert dust has been shown to set off bursts of phytoplankton growth.In addition to the Earth’s processes seen here, one remote sensing artifact is present. A diagonal streak of sunglint makes part of this scene appear washed out. Sunglint, an effect that occurs when sunlight reflects off the surface of the water at the same angle that a satellite sensor views it, is also the reason for the light-colored streaks trailing off the islands.NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Lindsey Doermann.View this area in EO ExplorerAn assortment of natural phenomena visible from space appeared together in one image.Image of the Day for August 17, 2023 Image of the Day Atmosphere Land Water View more Images of the Day:Flights were grounded as visibility was severely hampered by a Calima event. Image of the Day Atmosphere Land Dust and Haze Human Presence In one frame International Space Station astronauts were able to capture the evolution of fringing reefs to atolls. As with the Hawaiian Islands, these volcanic hot spot islands become progressively older to the northwest. As these islands move away from their magma sources they erode and subside. Image of the Day Land Water The dry, volcanic terrain of this Canary Island is suitable for lichen and crops … and for training astronauts. Image of the Day Land The event, known locally as “la calima,” turned skies orange and degraded air quality in Gran Canaria and neighboring islands. Image of the Day Atmosphere Land Dust and Haze July 17, 2023JPEGFour funnel-shaped estuarine inlets, collectively known as Rías Baixas, line the coast of Galicia, in northwest Spain. The nutrient-rich water in these inlets supports a wealth of marine life, making the Galicia coast one of the most productive places for aquaculture.On July 17, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9, acquired this image of the Rías de Arousa (Arousa estuary), the largest and northernmost of the inlets. Small dots skirt the coasts of the embayment. In most cases, these dots are rectangular rafts designed for raising bivalves like mussels. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy. Buoys keep the lattice mussel rafts afloat on the surface of the water, and hundreds of ropes are suspended into the water column from each structure. Mussels attach to the ropes and filter feed on phytoplankton and other suspended organic particles. The rafts allow for high yields of mussels in a small area of the water. The Rías Baixas are on the northern end of the Canary current and are in a major upwelling zone. Upwelling, which brings colder, nutrient-rich water up from the bottom of the ocean, typically occurs in this area between April and October. Much of the mussel production in the Rías Baixas occurs during this time, as the mollusks filter feed on nutrients and plentiful phytoplankton supported by upwelling. Spain is the top mussel producing country in the world. Rías de Arousa alone contains over 2,400 mussel rafts, producing about 40 percent of Europe’s mussels. NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerThe estuarine inlets of Spain’s Galicia coast are some of the most productive places to grow mussels.Image of the Day for September 19, 2023 Image of the Day Water Human Presence View more Images of the Day: Dust and Haze This image shows Tropical Cyclones Eric and Fanele near Madagascar on January 19, 2009. Atmosphere Water Severe Storms This natural-color image shows Saharan dust forming an S-shaped curve off the western coast of Africa, and passing directly over Cape Verde. Atmosphere Land Dust and Haze Acquired March 8, 2010, this true-color image shows two icebergs, Iceberg B-09B and an iceberg recently broken off the Mertz Glacier, floating in the Southern Ocean, just off the George V Coast. Water Snow and Ice Sea and Lake Ice May 18, 2023JPEGSeptember 7, 2023JPEGMay 18, 2023September 7, 2023May 18, 2023JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter going dry in 2018, Laguna de Aculeo has begun to refill. NASA satellites began to detect water pooling in the parched lake in late-August, after an intense winter storm dropped as much as 370 millimeters (15 inches) of rain on some parts of central Chile. The storm was fueled by an atmospheric river and exacerbated by the rugged terrain in central Chile.When the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired this image (right) on September 7, 2023, Laguna de Aculeo covered about 5 square kilometers (2 square miles) to a depth of roughly 1 meter (3 feet). The other image (left) shows the dried water body on May 18, 2023, before the wet winter weather arrived. Although it has refilled somewhat, water spans only half the area it did up to 2010 and contains a quarter of the water volume, explained René Garreaud, an Earth scientist at the University of Chile. Seasonal changes and the influx of water have led to widespread greening of the landscape around the lake.Researchers have assessed that ongoing development and water use in the nearby community of Paine, increasing water use by farmers and in homes and pools, as well as several years of drought, likely contributed to the drawdown of the lake. Annual rainfall deficits that averaged 38 percent between 2010 and 2018 likely played a large role, according to one analysis from a team of researchers from the University of Chile.Before 2010, the shallow water body was a popular haven for boaters, swimmers, and water skiers, but the water hasn’t yet pooled up enough for swimmers or boaters to return. It is also unclear how long the new water in Aculeo will persist. “Atmospheric rivers in June and August delivered substantial precipitation along the high terrain and foothills that have giv­­en us a welcome interruption to the drought,” Garreaud said. “But Aculeo is a small, shallow lagoon that can fill up rapidly, and it's only partly filled. Bigger reservoirs and aquifers will take much longer to recover.”NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe drought in Chile isn’t over, but recent late-winter rains provided enough moisture for water to start pooling up again.Image of the Day for September 16, 2023 Image of the Day Life Water View more Images of the Day:Data from winter 2022-2023 show the greatest net gain of water in nearly 22 years, but groundwater levels still suffer from years of drought. Image of the Day Land Water As a persistent drought drags on, water levels are dropping at a key reservoir that supplies Santiago. Image of the Day Land Water A new web tool designed by NASA applied scientists could help the tribe anticipate and respond to drought. Image of the Day Water Human Presence Remote Sensing For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001. Image of the Day Land Life September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 16, 2023September 10, 2021September 16, 2023JPEGSeptember 10, 2021JPEGSeptember 10, 2021JPEGMonths of excessive heat and drought parched the Mississippi River in the summer and early fall of 2023. In September, low water levels limited barge shipments downriver and threatened drinking water supplies in some Louisiana communities, according to the Associated Press.Water levels were especially low near Memphis, Tennessee. The images above show the Mississippi River near Memphis on September 16, 2023 (left), compared to September 10, 2021 (right). The river was significantly slimmed down in 2023, exposing some of the river bottom.This is the second year in a row drought has caused the river to fall to near-record lows at many gauges. On September 26, 2023, the river level at a gauge in Memphis was -10.26 feet, close to the record low level, -10.81 feet, measured at the same place on October 21, 2022. That was the lowest level recorded there since the start of National Weather Service records in 1954. Water levels, or “gauge heights,” do not indicate the depth of a stream; rather, they are measured with respect to a chosen reference point. That is why some gauge height measurements are negative.Farther upstream, water levels at New Madrid, Missouri, have been around -5 feet—near the minimum operating level—since early September 2023. Water levels on the Mississippi normally decline in the fall and winter, and in 2022, the river did not get that low until mid-October. September 26, 2023JPEGA hot, dry summer is the main reason water levels dropped so low in 2023. Across the globe, temperatures in summer 2023 were 1.2°C (2.1°F) warmer than average. In the U.S., Louisiana and Mississippi experienced their hottest Augusts on record, according to NOAA.The U.S. Drought Monitor map above—the product of a partnership between the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska-Lincoln—shows conditions during the week of September 20-26, 2023. The map depicts drought intensity in progressive shades of orange to red. It is based on an analysis of climate, soil, and water condition measurements from more than 350 federal, state, and local observers around the country. NASA contributes measurements and models that aid the drought monitoring effort.During that week, about 38 percent of the contiguous U.S. was experiencing drought. Lack of precipitation and high temperatures over several months severely dried out soils in states along the Mississippi River Valley. The Drought Monitor reported that 80 percent of soils in Louisiana were dry (short or very short on water) as of September 24. And for most states in the river valley, over 50 percent of topsoil was dry or very dry.Shallow conditions along the river interrupted normal shipments of goods. According to the Associated Press, barge companies reduced the weight carried in many shipments in September because the river was not deep enough to accommodate their normal weight. Much of U.S. grain exports are transported down the Mississippi, and according to AP, the cost of these shipments from St. Louis southward has risen 77 percent above the three-year average. The lack of freshwater flowing into the Gulf of Mexico has also allowed saltwater to make its way up the river and into some water treatment plants in southern Louisiana, according to the Associated Press. Some parts of Plaquemines Parish are under drinking water advisories and have relied on bottled water for cooking and drinking since June.Significant rainfall would be needed to flush out saltwater in the river in Plaquemines. According to the National Weather Service’s Lower Mississippi River Forecast Center, the forecast does not look promising. If enough rainfall doesn’t arrive before mid-to-late October, saltwater could make its way to New Orleans.NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and data from the United States Drought Monitor at the University of Nebraska-Lincoln. Story by Emily Cassidy.View this area in EO ExplorerIn September, low water levels made it more challenging to ship goods down the river and allowed a wedge of saltwater to move upstream.Image of the Day for October 1, 2023 Image of the Day Water Drought View more Images of the Day:Persistent dry conditions can affect water resources, ecosystems, and agriculture.Severe drought is reducing the number of daily passages on the transoceanic shipping route. Image of the Day Water Human Presence Prolonged drought in Kansas set the stage for what may be one of the state’s smallest wheat harvests in decades. Image of the Day Land Water Drought The most severe drought in 70 years of record keeping threatens the Horn of Africa with famine. Image of the Day Land Water Drought Low water levels are making it difficult to ship goods down the river and allowing a wedge of saltwater to move upstream. Image of the Day Land Water Human Presence Remote Sensing September 25, 2023JPEGLake Winnipeg, the world’s 10th largest freshwater lake by surface area, has experienced algae blooms at a regular occurrence at least since the 1990s. A bloom of blue-green algae once again covered parts of the lake in September 2023. Located in Manitoba, Canada, the long lake has a watershed that spans one million square kilometers (386,000 square miles), draining some of Canada’s agricultural land. The lake consists of a large, deep north basin and a smaller, comparatively shallow south basin. Swirls of algae filled the south basin of the lake on September 25, 2023, when the OLI-2 (Operational Land Imager-2) on Landsat 9 acquired this image. Around this time, satellite observations analyzed by Environment and Climate Change Canada indicated that algae covered about 8,400 square kilometers (3,200 square miles), or about a third of the lake’s area.Blue-green algae, also known as cyanobacteria, are single-celled organisms that rely on photosynthesis to turn sunlight into food. The bacteria grow swiftly when nutrients like phosphorus and nitrogen are abundant in still water. The bloom pictured here may contain blue-green algae, as well as other types of phytoplankton; only a surface sample can confirm the exact composition of a bloom. Some cyanobacteria produce microcystin—a potent toxin that can irritate the skin and cause liver and kidney damage.While algae are part of a natural freshwater ecosystem, excess algae, particularly cyanobacteria, can be a nuisance to residents and tourists using the lake and its beaches for fishing, swimming, and recreation. Beaches in the south basin of Lake Winnipeg can get as many as 30,000 visitors a day during the summer months. Water samples taken at Winnipeg Beach on the west shore found that cyanobacteria levels were elevated in August, and visitors were advised to avoid swimming and fishing if green scum was visible. The health of Lake Winnipeg has been in decline in recent decades. Between 1990 and 2000, phosphorous concentrations in the lake almost doubled and algae blooms proliferated, both in terms of occurrence and extent. The major contributors to the influx of phosphorous to the lake were increased agricultural activities in the watershed and a higher frequency of flooding, which has increased runoff into the lake.Phosphorus concentrations are almost three times higher in the south basin of Lake Winnipeg, compared to the north basin. A 2019 study using data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA’s Terra satellite found that the chlorophyll-a concentrations, which are used as a measure of phytoplankton biomass, were on average more than twice as high in the south basin, compared to the north. NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.View this area in EO ExplorerAn influx of nutrients in recent decades has contributed to the proliferation of algae in the large Canadian lake.Image of the Day for October 6, 2023 Image of the Day Water Water Color View more Images of the Day:Floating, plant-like organisms reproduce abundantly when there are sufficient nutrients, sunlight, and water conditions. Extreme blooms of certain species can become harmful to marine animals and humans.Cyanobacteria covered over half of the surface of Florida’s largest freshwater lake in mid-June 2023. Image of the Day Life Water Water Color Nearly half of the lake was covered with blue-green algae in early July 2022. Image of the Day Water Remote Sensing Water Color More than 40 years after the explosive eruption of Mount St. Helens, relics from the blast continue to haunt a nearby lake. Image of the Day Water Venezuela’s Lake Maracaibo is choking with oil slicks and algae. Image of the Day Life Water Human Presence Remote Sensing October 8, 2022JPEGOctober 3, 2023JPEGOctober 8, 2022October 3, 2023October 8, 2022JPEGOctober 3, 2023JPEGOctober 3, 2023JPEGJuly through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought.The OLI (Operational Land Imager) instrument on Landsat 8 captured this image (right) of the parched Rio Negro in the Brazilian province of Amazonas near the city of Manaus on October 3, 2023. On that date, the level of the river, the largest tributary of the Amazon River, had dropped to 15.14 meters (50.52 feet), according to data collected by the Port of Manaus. For comparison, the image on the left shows the same area on October 8, 2022, when the water level was 19.59 meters, a more typical level for October. Rio Negro water levels continued to drop in the days after the image was collected, reaching a record low of 13.49 meters on October 17, 2023.Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia.“Overall, this is a pretty unusual and extreme situation,” said René Garreaud, an atmospheric scientist at the University of Chile. “The primary culprit exacerbating the drought appears to be El Niño.” This cyclical warming of surface waters in the central-eastern Pacific functions somewhat like a boulder in the middle of a stream, disrupting atmospheric circulation patterns in ways that lead to wetter conditions over the equatorial Pacific and drier conditions over the Amazon Basin.According to news outlets, the low river water levels on the Rio Negro and other nearby rivers have disrupted drinking water supplies in hundreds of communities, slowed commercial navigation, and led to fish and dolphin die-offs.Manaus, the capital and largest city of the Brazilian state of Amazonas, is the primary transportation hub for the upper Amazon, serving as an important transit point for soap, beef, and animal hides. Other industries with a presence in the city of two million people include chemical, ship, and electrical equipment manufacturing.NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.View this area in EO ExplorerThe water level of the largest tributary of the Amazon River has hit a record low.Image of the Day for October 18, 2023 Image of the Day Water Human Presence View more Images of the Day:The impact of severe drought on the Negro River, a tributary of the Amazon River, and other rivers in the basin is dramatically evident in this pair of images, which show that every body of water has shrunk in 2010 compared to 2008. Image of the Day Atmosphere Land The volume of water in New Mexico’s largest reservoir has dropped to historic lows due to drought and persistent demand. Image of the Day Water Human Presence Acquired June 25, 2011, and June 22, 2010, these false-color images compare conditions along the Souris River, which reached a historic crest at Minot, North Dakota in June 2011. Land Floods Acquired May 11, 2011, and April 21, 2007, these false-color images show the Mississippi River near Natchez, Mississippi. The image from May 2011 shows flooded conditions. Land Floods September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 6, 2020September 7, 2023September 6, 2020JPEGSeptember 7, 2023JPEGSeptember 7, 2023JPEGAfter rapidly growing in volume just a few years earlier, northwest Iran’s Lake Urmia nearly dried out in autumn 2023. The largest lake in the Middle East and one of the largest hypersaline lakes on Earth at its greatest extent, Lake Urmia has for the most part transformed into a vast, dry salt flat. On September 7, 2023, the OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (right) of the desiccated lakebed. It stands in contrast to the image from three years earlier (left), acquired by the OLI on Landsat 8 on September 8, 2020, when water filled most of the basin and salt deposits were only visible around the perimeter of the lake. The replenishment followed a period of above-average precipitation that sent a surge of freshwater into the basin, expanding its watery footprint. Drier conditions have since brought levels back down. The longer-term trend for Urmia has been one toward drying. In 1995, Lake Urmia reached a high-water mark; then in the ensuing two decades, the lake level dropped more than 7 meters (23 feet) and lost approximately 90 percent of its area. Consecutive droughts, agricultural water use, and dam construction on rivers feeding the lake have contributed to the decline. A shrinking Lake Urmia has implications for ecological and human health. The lake, its islands, and surrounding wetlands comprise valuable habitat and are recognized as a UNESCO Biosphere Reserve, Ramsar site, and national park. The area provides breeding grounds for waterbirds such as flamingos, white pelicans, and white-headed ducks, as well as a stopover for migratory species. However, with low lake levels, what water remains becomes more saline and taxes the populations of brine shrimp and other food sources for larger animals. A shrinking lake also increases the likelihood of dust from the exposed lakebed becoming swept up by winds and degrading air quality. Recent studies have linked the low water levels in Lake Urmia with respiratory health impacts among the local population.The relative effects of climate, water usage, and dams on Lake Urmia’s water level is a topic of debate. The lake did see some recovery during a 10-year restoration program beginning in 2013. However, the efficacy of that effort has been difficult to parse since strong rains also fell during that period. Some research has concluded that climatic factors were primarily responsible for the recovery. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.View this area in EO ExplorerA few years after a fresh influx of water raised its levels, the large lake has nearly gone dry.Image of the Day for October 10, 2023 Image of the Day Land Water View more Images of the Day:Water levels are at their lowest since 1937. Image of the Day Water Drought Fires Long and short. Deep and shallow. Salty and fresh. Blue and brown. These are Africa’s Lake Tanganyika and Lake Rukwa. Image of the Day Land Water In May 2016, the reservoir behind Hoover Dam reached its lowest level since the 1930s. Image of the Day Water When the water gets saltier in Iran’s largest lake, the microscopic inhabitants can turn the water dark red. Image of the Day Water Water Color July 1 - September 30, 2023MPEG For several months in 2023, global sea surface temperatures reached record-high levels, fueled by decades of human-caused climate warming and a recent boost from the natural climate phenomenon El Niño. Some areas—including the seas around Florida, Cuba, and the Bahamas—saw particularly high temperatures, with implications for the health of coral reefs.Corals thrive within a small range of temperatures and become stressed when water is too hot or cold. Bleaching occurs when stressed corals expel the algae that live inside them, stripping corals of their color. Extreme bleaching can leave a reef susceptible to starvation, disease, and even death. Observations made by divers in the Florida Keys found that the marine heatwave in summer 2023 caused widespread bleaching.Stress on corals can also be detected using data from satellites. This animation shows the evolution of accumulated heat stress from July through September 2023. The colors depict “degree heating weeks” (°C-weeks)—a measure that provides an estimate of the severity and duration of thermal stress. Data for the product are compiled by NOAA’s Coral Reef Watch, which blends observations from polar orbiting satellites such as the NASA-NOAA Suomi NPP, and from geostationary satellites such as GOES, with computer models.Observations have shown that when the accumulated heat stress reaches a value of 4, significant coral bleaching can result. At values of 8, coral bleaching and widespread mortality are likely. By midway through this animation, in August, heat stress across much of the region already soared well above both of those thresholds. According to NOAA, cumulative heat stress by late September 2023 hit 22°C-weeks (40°F-weeks), nearly triple the previous record for the region.Bleaching was already observed in some areas as early as July. Notice that areas of coral reef (gray) near the Florida Keys, Cuba, and the Bahamas, are among the first areas to show high cumulative heat stress. Hurricane Idalia in late August helped cool surface waters somewhat, but only temporarily.Nearing mid-October, waters around the Florida Keys were under a bleaching watch. Further south, waters around parts of Cuba and the Bahamas remained at bleaching alert level 2, the highest level of the scale, signifying that severe bleaching and mortality are likely.NASA Earth Observatory animation by Wanmei Liang, using Daily 5km Degree Heating Weeks data from Coral Reef Watch. Coral reef data from UNEP-WCMC, WorldFish Centre, WRI, TNC. Story by Kathryn Hansen.View this area in EO ExplorerThe seas around Florida, Cuba, and the Bahamas saw large accumulations of heat stress beginning in summer 2023, with implications for the health of coral reefs.Image of the Day for October 16, 2023 Image of the Day Water Temperature Extremes View more Images of the Day:Warmer-than-average temperatures are showing up locally and globally, with consequences for people, landscapes, and ecosystems. Image of the Day Water Image of the Day Life Water Image of the Day Heat Life Water Studying corals from above could help scientists understand how these critical ecosystems will weather a changing climate. Image of the Day Land Life Water Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.Advertisement Scientific Data volume 7, Article number: 112 (2020) Cite this article 30k Accesses126 Citations88 AltmetricMetrics detailsRemotely sensed biomass carbon density maps are widely used for myriad scientific and policy applications, but all remain limited in scope. They often only represent a single vegetation type and rarely account for carbon stocks in belowground biomass. To date, no global product integrates these disparate estimates into an all-encompassing map at a scale appropriate for many modelling or decision-making applications. We developed an approach for harmonizing vegetation-specific maps of both above and belowground biomass into a single, comprehensive representation of each. We overlaid input maps and allocated their estimates in proportion to the relative spatial extent of each vegetation type using ancillary maps of percent tree cover and landcover, and a rule-based decision schema. The resulting maps consistently and seamlessly report biomass carbon density estimates across a wide range of vegetation types in 2010 with quantified uncertainty. They do so for the globe at an unprecedented 300-meter spatial resolution and can be used to more holistically account for diverse vegetation carbon stocks in global analyses and greenhouse gas inventories.Measurement(s)biomass carbon densityTechnology Type(s)digital curationFactor Type(s)climatic zone • above or below ground • land coverSample Characteristic - Environmentorganic materialSample Characteristic - LocationEarth (planet)Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.11872383Terrestrial ecosystems store vast quantities of carbon (C) in aboveground and belowground biomass1. At any point in time, these stocks represent a dynamic balance between the C gains of growth and C losses from death, decay and combustion. Maps of biomass are routinely used for benchmarking biophysical models2,3,4, estimating C cycle effects of disturbance5,6,7, and assessing biogeographical patterns and ecosystem services8,9,10,11. They are also critical for assessing climate change drivers, impacts, and solutions, and factor prominently in policies like Reducing Emissions from Deforestation and Forest Degradation (REDD+) and C offset schemes12,13,14. Numerous methods have been used to map biomass C stocks but their derivatives often remain limited in either scope or extent12,15. There thus remains a critical need for a globally harmonized, integrative map that comprehensively reports biomass C across a wide range of vegetation types.Most existing maps of aboveground biomass (AGB) and the carbon it contains (AGBC) are produced from statistical or data-driven methods relating field-measured or field-estimated biomass densities and spaceborne optical and/or radar imagery12,15,16. They largely focus on the AGB of trees, particularly those in tropical landscapes where forests store the majority of the region’s biotic C in aboveground plant matter. Land cover maps are often used to isolate forests from other landcover types where the predictive model may not be appropriate such that forest AGB maps intentionally omit AGB stocks in non-forest vegetation like shrublands, grasslands, and croplands, as well as the AGB of trees located within the mapped extent of these excluded landcovers17. Non-forest AGB has also been mapped to some extent using similar approaches but these maps are also routinely masked to the geographic extent of their focal landcover18,19,20,21. To date, there has been no rigorous attempt to harmonize and integrate these landcover-specific, remotely sensed products into a single comprehensive and temporally consistent map of C in all living biomass.Maps of belowground biomass (BGB) and carbon density (BGBC) are far less common than those of AGB because BGB cannot be readily observed from space or airborne sensors. Consequently, BGB is often inferred from taxa-, region-, and/or climate-specific “root-to-shoot” ratios that relate the quantity of BGB to that of AGB22,23,24. These ratios can be used to map BGB by spatially applying them to AGB estimates using maps of their respective strata5. In recent years, more sophisticated regression-based methods have been developed to predict root-to-shoot ratios of some landcover types based on covariance with other biophysical and/or ecological factors25,26. When applied spatially, these methods can allow for more continuous estimates of local BGB5,27. Like AGBC, though, few attempts have been made to comprehensively map BGBC for the globe.Despite the myriad of emerging mapping methods and products, to date, the Intergovernmental Panel on Climate Change (IPCC) Tier-1 maps by Ruesch and Gibbs28 remains the primary source of global AGBC and BGBC estimates that transcend individual landcover types. These maps, which represents the year 2000, were produced prior to the relatively recent explosion of satellite-based AGB maps and they therefore rely on an alternative mapping technique called “stratify and multiply”15, which assigns landcover-specific biomass estimates or “defaults” (often derived from field measurements or literature reviews) to the corresponding classified grid cells of a chosen landcover map12. While this approach yields a comprehensive wall-to-wall product, it can fail to capture finer-scale spatial patterns often evident in the field and in many satellite-based products12,15. The accuracy of these maps is also tightly coupled to the quality and availability of field measurements29 and the thematic accuracy and discontinuity of the chosen landcover map.Given the wealth of landcover-specific satellite based AGB maps, a new harmonization method akin to “stratify and multiply” is needed to merge the validated spatial detail of landcover-specific remotely sensed biomass maps into a single, globally harmonized product. We developed such an approach by which we (i) overlay distinct satellite-based biomass maps and (ii) proportionately allocate their estimates to each grid cell (“overlay and allocate”). Specifically, we overlay continental-to-global scale remotely sensed maps of landcover-specific biomass C density and then allocate fractional contributions of each to a given grid cell using additional maps of percent tree cover, thematic landcover and a rule-based decision tree. We implement the new approach here using temporally consistent maps of AGBC as well as matching derived maps of BGBC to generate separate harmonized maps of AGBC and BGBC densities. In addition, we generate associated uncertainty layers by propagating the prediction error of each input dataset. The resulting global maps consistently represent biomass C and associated uncertainty across a broad range of vegetation in the year 2010 at an unprecedented 300 meter (m) spatial resolution.Our harmonization approach (Fig. 1) relies on independent, landcover-specific biomass maps and ancillary layers, which we compiled from the published literature (Table 1). When published maps did not represent our epoch of interest (i.e. grasslands and croplands) or did not completely cover the necessary spatial extent (i.e. tundra vegetation), we used the predictive model reported with the respective map to generate an updated version that met our spatial and temporal requirements. We then used landcover specific root-to-shoot relationships to generate matching BGBC maps for each of the input AGBC maps before implementing the harmonization procedure. Below we describe, in detail, the methodologies used for mapping AGBC and BGBC of each landcover type and the procedure used to integrate them.Generalized, three-step workflow used to create harmonized global biomass maps. In step one, woody AGB maps are prepared, combined, converted to AGBC density and used to create separate but complementary maps of BGBC. In step two, a similar workflow is used to generate matching maps of AGBC and BGBC for tundra vegetation, grasses, and annual crops. In step three, all maps are combined using a rule-based decision tree detailed in Fig. 3 to generate comprehensive, harmonized global maps. All input data sources are listed and described in Table 1.Since the first remotely sensed woody AGB maps were published in the early 1990s, the number of available products has grown at an extraordinary pace16 and it can thus be challenging to determine which product is best suited for a given application. For our purposes, we relied on the GlobBiomass AGB density map30 as our primary source of woody AGB estimates due to its precision, timestamp, spatial resolution, and error quantification. It was produced using a combination of spaceborne optical and synthetic aperture radar (SAR) imagery and represents the year 2010 at a 100 m spatial resolution – making it the most contemporary global woody AGB currently available and the only such map available for that year. Moreover, GlobBiomass aims to minimize prediction uncertainty to less than 30% and a recent study suggests that it has high fidelity for fine-scale applications31.The GlobBiomass product was produced by first mapping the growing stock volume (GSV; i.e. stem volume) of living trees, defined following Food and Agriculture Organization (FAO) guidelines32 as those having a diameter at breast height (DBH) greater than 10 centimeters (cm). AGB density was then determined from GSV by applying spatialized biomass expansion factors (BEFs) and wood density estimates. These factors were mapped using machine learning methods trained from a suite of plant morphological databases that compile thousands of field measurements from around the globe33. The resulting AGB estimates represent biomass in the living structures (stems, branches, bark, twigs) of trees with a DBH greater than 10 cm. This definition may thereby overlook AGB of smaller trees and/or shrubs common to many global regions. Unlike other maps, though, the GlobBiomass product employs a subpixel masking procedure that retains AGB estimates in 100 m grid cells in which any amount of tree cover was detected in finer resolution (30 m) imagery34. This unique procedure retains AGB estimates in tree-sparse regions like savannahs, grasslands, croplands, and agroforestry systems where AGB is often overlooked17, as well as in forest plantations. The GlobBiomass product is the only global map that also includes a dedicated uncertainty layer reporting the standard error of prediction. We used this layer to propagate uncertainty when converting AGB to AGBC density, modelling BGBC, and integrating with C density estimates of other vegetation types.Bouvet et al.35 – some of whom were also participants of the GlobBiomass project – independently produced a separate AGB density map for African savannahs, shrublands and dry woodlands circa 2010 at 25 m spatial resolution35 (hereafter “Bouvet map”), which we included in our harmonized product to begin to address the GlobBiomass map’s potential omission of small trees and shrubs that do not meet the FAO definition of woody AGB. This continental map of Africa is based on a predictive model that directly relates spaceborne L-band SAR imagery – an indirect measure of vegetation structure that is sensitive to low biomass densities36 – with region-specific, field-measured AGB. Field measurements (n = 144 sites) were compiled from 7 different sampling campaigns – each specifically seeking training data for biomass remote sensing – that encompassed 8 different countries35. The resulting map is not constrained by the FAO tree definition and is masked to exclude grid cells in which predicted AGB exceeds 85 megagrams dry mater per hectare (Mg ha−1) – the threshold at which the SAR-biomass relationship saturates. To avoid extraneous prediction, it further excludes areas identified as “broadleaved evergreen closed-to-open forest”, “flooded forests”, “urban areas” and “water bodies” by the European Space Agency’s Climate Change Initiative (CCI) Landcover 2010 map37 and as “bare areas” in the Global Land Cover (GLC) 2000 map38. While the Bouvet map is not natively accompanied by an uncertainty layer, its authors provided us with an analytic expression of its uncertainty (SE; standard error of prediction) as a function of estimated AGB (Eq. 1) which we used to generate an uncertainty layer for subsequent error propagation.We combined the GlobBiomass and Bouvet products to generate a single woody biomass map by first upscaling each map separately to a matching 300 m spatial resolution using an area-weighted average to aggregate grid cells, and then assigning the Bouvet estimate to all overlapping grid cells, except those identified by the CCI Landcover 2010 map as closed or flooded forest types (Online-only Table 1) which were not within the dryland domain of the Bouvet map. While more complex harmonization procedures based on various averaging techniques have been used by others39,40, their fidelity remains unclear since they fail to explicitly identify and reconcile the underlying source of the inputs’ discrepancies41. We thus opted to use a more transparent ruled-based approach when combining these two woody biomass maps, which allows users to easily identify the source of a grid cell’s woody biomass estimate. Given the local specificity of the training data used to produce the Bouvet map, we chose to prioritize its predictions over those of the GlobBiomass product when within its domain. In areas of overlap, the Bouvet map values tend to be lower in moist regions and higher in dryer regions (Fig. 2), though, where used, these differences rarely exceed ±25 megagrams C per hectare (MgC ha−1).Difference between underlying woody aboveground biomass maps in Africa. Maps considered are the GlobBiomass30 global map and the Bouvet35 map of Africa. Both maps were aggregated to a 300 m spatial resolution and converted to C density prior to comparison using the same schema. The difference map was subsequently aggregated to a 3 km spatial resolution and reprojected for visualization. Negative values denote lower estimates by Bouvet et al.35, while positive values denote higher estimates.We then converted all woody AGB estimates to AGBC by mapping climate and phylogeny-specific biomass C concentrations from Martin et al.42. Climate zones were delineated by aggregating classes of the Köppen-Gieger classification43 (Table 2) to match those of Martin et al.42. Phylogenetic classes (angiosperm, gymnosperm and mixed/ambiguous) were subsequently delineated within each of these zones using aggregated classes of the CCI Landcover 2010 map (Online-only Table 1). Martin et al.42 only report values for angiosperms and gymnosperms so grid cells with a mixed or ambiguous phylogeny were assigned the average of the angiosperm and gymnosperm values and the standard error of this value was calculated from their pooled variance. Due to residual classification error in the aggregated phylogenetic classes, we weighted the phylogeny-specific C concentration within each climate zone by the binary probability of correctly mapping that phylogeny (i.e. user’s accuracy)44 using Eq. 2where, within each climate zone, μc is the mean probability-weighted C concentration of the most probable phylogeny, μm is the mean C concentration of that phylogeny from Martin et al.42, pm is the user’s accuracy of that phylogeny’s classification (Table 3), and μn and μo are the mean C concentrations of the remain phylogenetic classes from Martin et al.42. Standard error estimates for these C concentrations were similarly weighted using summation in quadrature (Eq. 3)where \({\sigma }_{c}\) is the probability-weighted standard error of the most probable phylogeny’s C concentration and \({\sigma }_{m}\), \({\sigma }_{n}\) and \({\sigma }_{o}\) are the standard errors of the respective phylogeny-specific C concentrations from Martin et al.42. Probability-weighted C concentrations used are reported in Table 4.Mapped, probability-weighted C estimates were then arithmetically applied to AGB estimates. Uncertainty associated with this correction was propagated using summation in quadrature of the general form (Eq. 4)where \({\mu }_{f}=f(i,j,\ldots ,k)\), \({\sigma }_{f}\) is the uncertainty of μf, and \({\sigma }_{i},{\sigma }_{j},\ldots ,{\sigma }_{k}\), are the respective uncertainty estimates of the dependent parameters (standard error unless otherwise noted). Here, μf, is the estimated AGBC of a given grid cell, and is the product of its woody AGB estimate, and its corresponding C concentration.The tundra and portions of the boreal biome are characterized by sparse trees and dwarf woody shrubs as well as herbaceous cover that are not included in the GlobBiomass definition of biomass. AGB density of these classes has been collectively mapped by Berner et al.18,45 for the North Slope of Alaska from annual Landsat imagery composites of the normalized difference vegetation index (NDVI) and a non-linear regression-based model trained from field measurements of peak AGB that were collected from the published literature (n = 28 sites). Berner et al.18 note that while these field measurements did not constitute a random or systematic sample, they did encompass a broad range of tundra plant communities. In the absence of a global map and due the sparsity of high quality Landsat imagery at high latitudes, we extended this model to the pan-Arctic and circumboreal regions using NDVI composites created from daily 250 m MODIS Aqua and Terra surface reflectance images46,47 that were cloud masked and numerically calibrated to Landsat ETM reflectance – upon which the tundra model is based – using globally derived conversion coefficients48. We generated six separate 80th percentile NDVI composites circa 2010 – one for each of the MODIS missions (Aqua and Terra) in 2009, 2010 and 2011 – following Berner et al.18. We chose to use three years of imagery (circa 2010) rather than just one (2010) to account for the potential influence that cloud masking may exert upon estimates of the 80th NDVI percentile in a single year. We then applied the tundra AGB model to each composite, converted AGB estimates to AGBC by assuming a biomass C fraction of 49.2% (SE = 0.8%)42 and generated error layers for each composite from the reported errors of the AGB regression coefficients and the biomass C conversion factor using summation in quadrature as generally described above (Eq. 4). A single composite of tundra AGBC circa 2010 was then created as the pixelwise mean of all six composites. We also generated a complementary uncertainty layer representing the cumulative standard error of prediction, calculated as the pixelwise root mean of the squared error images in accordance with summation in quadrature. Both maps were upscaled from their native 250 m spatial resolution to a 300 m spatial resolution using an area weighted aggregation procedure, whereby pixels of the 300 m biomass layer was calculated as the area weighted average of contained 250 m grid cells, and the uncertainty layer was calculated – using summation in quadrature – as the root area-weighted average of the contained grid cells squared.Grassland AGBC density was modelled directly from maximum annual NDVI composites using a non-linear regression-based model developed by Xia et al.19 for mapping at the global scale. This model was trained by relating maximum annual NDVI as measured by the spaceborne Advanced Very High-Resolution Radiometer (AVHRR) sensor to globally distributed field measurements of grassland AGBC that were compiled from the published literature (81 sites for a total of 158 site-years). Like the tundra biomass training data, these samples did not constitute a random or systematic sample but do encompass a comprehensive range of global grassland communities. Given the inevitable co-occurrence of trees in the AVHRR sensor’s 8 km resolution pixels upon which the model is trained, it’s predictions of grassland AGBC are relatively insensitive to the effects of co-occurring tree cover. We thereby assume that its predictions for grid cells containing partial tree cover represent the expected herbaceous AGBC density in the absence of those trees. Maximum model predicted AGBC (NDVI = 1) is 2.3 MgC ha−1 which is comparable to the upper quartile of herbaceous AGBC estimates from global grasslands49 and suggests that our assumption will not lead to an exaggerated estimation. For partially wooded grid cells, we used modelled grassland AGBC density to represent that associated with the herbaceous fraction of the grid cell in a manner similar to Zomer et al.17 as described below (See “Harmonizing Biomass Carbon Maps”).We applied the grassland AGBC model to all grid cells of maximum annual NDVI composites produced from finer resolution 16-day (250 m) MODIS NDVI imagery composites circa 201050,51. Here again, three years of imagery were used to account for potential idiosyncrasies in a single year’s NDVI composites resulting from annual data availability and quality. As with AGB of tundra vegetation, annual composites (2009–2011) were constructed separately from cloud-masked imagery collected by both MODIS missions (Aqua and Terra; n = 6) and then numerically calibrated to AVHRR reflectance using globally derived conversion coefficients specific to areas of herbaceous cover52. We then applied the AGBC model to each of these composites and estimated error for each composite from both the AVHRR calibration (standard deviation approximated from the 95% confidence interval of the calibration scalar) and the AGBC model (relative RMSE) using summation in quadrature. A single map of grassland AGBC circa 2010 was then created as the pixelwise mean of all six composites and an associated error layer was created as the pixelwise root mean of the squared error images. Both maps were aggregated from their original 250 m resolution to 300 m to facilitate harmonization using the area-weighted procedure described previously for woody and tundra vegetation (see section 1.2).Prior to harvest, cropland biomass can also represent a sizable terrestrial C stock. In annually harvested cropping systems, the maximum standing biomass of these crops can be inferred from annual net primary productivity (ANPP). While spaceborne ANPP products exist, they generally perform poorly in croplands53,54. Instead, cropland ANPP is more commonly derived from crop yields20,21,53. We used globally gridded, crop-specific yields of 70 annually harvested herbaceous commodity crops circa 2000 by Monfreda et al.20 – the only year in which these data were available. These maps were produced by spatially disaggregating crop-yield statistics for thousands of globally distributed administrative units throughout the full extent of a satellite-based cropland map20. These maps were combined with crop-specific parameters (Online-only Table 2) to globally map AGBC as aboveground ANPP for each crop following the method of Wolf et al.21. This method can be simplified as (Eq. 5)where y is the crop’s yield (Mg ha−1), ω is the dry matter fraction of its harvested biomass, h is its harvest index (fraction of total AGB collected at harvest) and c is the carbon content fraction of its harvested dry mass. This simplification assumes, following Wolf et al.21, that 2.5% of all harvested biomass is lost between the field and farmgate and that unharvested residue and root mass is 44% C.Total cropland AGBC density was then calculated as the harvested-area-weighted average of all crop-specific AGBC estimates within a given grid cell. Since multiple harvests in a single year can confound inference of maximum AGBC from ANPP, we further determined the harvest frequency (f) of each grid cell by dividing a cell’s total harvested area (sum of the harvested area of each crop reported within a given grid cell) by its absolute cropland extent as reported in a complementary map by Ramankutty et al.55. If f was greater than one, multiple harvests were assumed to have occurred and AGBC was divided by f to ensure that AGBC estimates did not exceed the maximum standing biomass density.Since the yields of many crops and, by association, their biomass have changed considerably since 200056,57, we calibrated our circa 2000 AGBC estimates to the year 2010 using local rates of annual ANPP change (MgC ha−1 yr−1) derived as the Theil-Sen slope estimator – a non-parametric estimator that is relatively insensitive to outliers – of the full MODIS Terra ANPP timeseries (2000–2015)58. Total ANPP change between 2000 and 2010 for each grid cell was calculated as ten times this annual rate of change. Since MODIS ANPP represents C gains in both AGB and BGB, we proportionately allocated aboveground ANPP to AGBC using the total root-to-shoot ratio derived from the circa 2000 total crop AGBC and BGBC maps (described below). Since error estimates were not available for the yield maps or the crop-specific parameters used to generate the circa 2000 AGBC map, estimated error of the circa 2010 crop AGBC map was exclusively based on that of the 2000–2010 correction. The error of this correction was calculated as the pixel-wise standard deviation of bootstrapped simulations (n = 1000) in which a random subset of years was omitted from the slope estimator in each iteration. The 8 km resolution circa 2000 AGBC map and error layer were resampled to 1 km to match the resolution of MODIS ANPP using the bilinear method prior to ANPP correction and then further resampled to 300 m to facilitate harmonization.Woody crops like fruit, nut, and palm oil plantations were not captured using the procedure just described and their biomass was instead assumed to be captured by the previously described woody biomass products which retained biomass estimates in all pixels where any amount of tree cover was detected at the sub-pixel level (see section 1.1).Matching maps of BGBC and associated uncertainty were subsequently produced for each of the landcover-specific AGBC maps using published empirical relationships.With the exception of savannah and shrubland areas, woody BGBC was modelled from AGBC using a multiple regression model by Reich et al.25 that considers the phylogeny, mean annual temperature (MAT), and regenerative origin of each wooded grid cell and that was applied spatially using maps of each covariate in a fashion similar to other studies5,27. Tree phylogeny (angiosperm or gymnosperm) was determined from aggregated classes of the CCI Landcover 2010 map37 (Online-only Table 1) with phylogenetically mixed or ambiguous classes assumed to be composed of 50% of each. MAT was taken from version 2 of the WorldClim bioclimatic variables dataset (1970–2000) at 1 km resolution59 and resampled to 300 m using the bilinear method. Since there is not a single global data product mapping forest management, we determined tree origin – whether naturally propagated or planted – by combining multiple data sources. These data included (i) a global map of “Intact Forest Landscapes” (IFL) in the year 201360 (a conservative proxy of primary, naturally regenerating forests defined as large contiguous areas with minimal human impact), (ii) a Spatial Database of Planted Trees (SDPT) with partial global coverage61, (iii) national statistics reported by the FAO Global Forest Resources Assessment (FRA) on the extent of both naturally regenerating and planted forests and woodlands within each country in the year 201062, and (iv) national statistics reported by the FAOSTAT database (http://www.fao.org/faostat) on the planted area of plantation crops in 2010. Within each country, we assumed that the total area of natural and planted trees was equal to the corresponding FRA estimates. If the FAOSTAT-reported area of tree crops exceeded FRA-reported planted area, the difference was added to FRA planted total. All areas mapped as IFL were assumed to be of natural origin and BGB was modelled as such. Likewise, besides the exceptions noted below, all tree plantations mapped by the SDPT were assumed to be of planted origin. In countries where the extent of the IFL or SDPT maps fell short of the FRA/FAOSTAT reported areas of natural or planted forests, respectively, we estimated BGBC in the remaining, unknown-origin forest grid cells of that country (BGBCu), as the probability-weighted average of the planted and natural origin estimates using Eq. 6where \(BGB{C}_{p}\) and \(BGB{C}_{n}\) are the respective BGBC estimates for a grid cell assuming entirely planted and natural origin, respectively, and \({\Delta }_{p}\) and \({\Delta }_{n}\) are the respective differences between (i) the FRA/FAOSTAT and (ii) mapped extent of planted and natural forest within the given grid cell’s country. While the mapped extent of IFL forests within a given country never exceeded that country’s FRA reported natural forest extent, there were infrequent cases (n = 22 of 257) in which the mapped extent of tree plantations exceeded the corresponding FRA/FAOSTAT estimate of planted forest area. In these cases, we down-weighted the BGB estimates of SDPT forests in a similar fashion such that the weight of their planted estimate (\({\omega }_{p}\)) was equal to the quotient of (i) the FRA/FAOSTAT planted area and (ii) the SDPT extent within the country, and the weight of the natural origin estimate applied to the SDPT extent (\({\omega }_{n}\)) was equal to \(1-{\omega }_{p}\).A BGBC error layer was then produced using summation in quadrature from the standard error estimates of the model coefficients, the AGBC error layer, the relative RMSE of MAT (27%), and the derived global uncertainty of the phylogeny layer. Phylogeny error was calculated as the Bernoulli standard deviation (δ) of the binary probability (p) of correct classification (i.e. “area weighted user’s accuracy”44; Table 3) using Eq. 7.Since savannahs and shrublands are underrepresented in the regression-based model25, their BGBC was instead estimated using static root-to-shoot ratios reported by Mokany et al.22, which are somewhat conservative in comparison to the IPCC Tier-1 defaults23,24 put favoured for consistency with methods used for grasslands (see below). Error was subsequently mapped from that of the AGBC estimates and the root-to-shoot ratios applied (Table 5).BGBC of tundra vegetation was mapped from AGBC using a univariate regression model derived by Wang et al.26 that predicts root-to-shoot ratio as a function of MAT. We applied the model using the WorldClim version 2 MAT map59 and propagated error from the AGBC estimates, the relative RMSE of MAT and the standard error of regression coefficients. Where tundra AGB exceeded 25 Mg ha−1 – the maximum field-measured shrub biomass reported by Berner et al.18 – vegetation was considered to include trees and the Reich et al.25 method described earlier for woody vegetation was used instead.In the absence of a continuous predictor of grassland root-to-shoot ratios, we applied climate specific root-to-shoot ratios from Mokany et al.22 to the corresponding climate regions of the Köppen-Gieger classification43 (Table 2). Here, again, these ratios vary slightly from the IPCC Tier-1 defaults23,24 but were chosen for their greater sample size and specificity. Grassland BGBC error was mapped from the error of the AGBC estimates and the respective root-to-shoot ratios.Cropland BGBC was again estimated from crop-specific yields and morphological parameters (Online-only Table 2) following Wolf et al.21 and Eq. 8where y is the crop’s yield (Mg ha−1), r is the root-to-shoot ratio of the crop, and h is its harvest index. Here again we assume that 2.5% of all harvested biomass is lost between the field and farmgate and that root biomass is 44% C, following Wolf et al.21. BGBC error was mapped from the error of the 2000-to-2010 ANPP correction for BGBC allocation as described above for cropland AGBC.The AGBC and BGBC maps were harmonized separately following the same general schema (Fig. 3). Given that our harmonized woody biomass map contains biomass estimates for grid cells in which any amount of tree cover was detected at the subpixel level (see section 1.1), we conserved its estimates regardless of the landcover reported by the 2010 CCI map in order to more fully account for woody biomass in non-forested areas17. We then used the MODIS continuous vegetation fields percent tree cover map for 201063 to allocate additional biomass density associated with the most probable herbaceous cover (grass or crop) to each grid cell in quantities complementary to that of the grid cell’s fractional tree cover estimate (Eq. 9)where μT is the total biomass estimate of a grid cell, μw is the woody biomass estimate for the grid cell, μh is its herbaceous biomass estimate, and q is the MODIS fractional tree cover of the grid cell. Since MODIS tree cover estimates saturate at around 80%64, we linearly stretched values such that 80% was treated as complete tree cover (100%). Moreover, we acknowledge that percent cover can realistically exceed 100% when understory cover is considered but we were unable to reasonably determine the extent of underlying cover from satellite imagery. As such, our approach may underestimate the contribution of herbaceous C stocks in densely forested grid cells. The most likely herbaceous cover type was determined from the CCI Landcover 2010 map, which we aggregated into two “likely herbaceous cover” classes – grass or crop – based on the assumed likelihood of cropland in each CCI class (Online-only Table 1). However, due to inherent classification error in the native CCI Landcover map, when determining the herbaceous biomass contribution we weighted the relative allocation of crop and grass biomass to a given grid cell based on the probability of correct classification by the CCI map (i.e. “user’s accuracy”, Table 6) of the most probable herbaceous class (\({p}_{i}\)) such that μh can be further expressed as (Eq. 10)where μi is the predicted biomass of the most probable herbaceous class, and μj is that of the less probable class.Decision tree used to allocate landcover-specific biomass estimates to each grid cell of our harmonized global products.The uncertainty of a grid cell’s total AGBC or BGBC estimate (\({\sigma }_{T}\)) was determined and mapped from that of its components (\({\mu }_{w}\,{\rm{and}}\,{\mu }_{h}\)) by summation in quadrature which can be simplified as (Eq. 11)where \({\sigma }_{w}\) is the error of the grid cell’s estimated μw, \({\sigma }_{h}\) is the error of its estimated μh, and \({\sigma }_{q}\) is the error of its q. Here, \({\sigma }_{h}\) can be further decomposed and expressed as Eq. 12 to account for the accuracy weighted allocation procedure expressed previously (Eq. 10)where \({\sigma }_{i}\) is the error of the estimated biomass density of the most probable herbaceous class, \({\delta }_{i}\) is the estimated standard deviation of that class’s Bernoulli probability (p; Eq. 7), and \({\sigma }_{j}\) is the error of the estimated biomass density of the less probable herbaceous subclass.Exceptions to the above schema were made in the tundra and boreal biomes – as delineated by the RESOLVE Ecoregions 2017 biome polygons65 – where thematic overlap was likely between the woody and tundra plant biomass maps. A separate set of decision rules (Fig. 3) was used to determine whether grid cells in these biomes were to be exclusively allocated the estimate of the tundra plant map or that of the fractional allocation procedure described above. In general, any land in these biomes identified as sparse landcover by the CCI landcover map (Online-only Table 1) was assigned the tundra vegetation estimate. In addition, lands north of 60° latitude with less than 10% tree cover or where the tundra AGBC estimate exceeded that of the woody AGBC estimate were also exclusively assigned the tundra vegetation estimate. Lands north of 60° latitude not meeting these criteria were assigned the woody value with the additional contribution of grass.Subtle numerical artefacts emerged from the divergent methodologies employed north and south of 60°N latitude. These were eliminated by distance weighting grid cells within 1° of 60°N based on their linear proximity to 60°N and then averaging estimates such that values at or north of 61°N were exclusively based on the northern methodology, those at 60°N were the arithmetic average of the two methodologies and those at or south of 59°N were exclusively based on the southern methodology. This produced a seamless, globally harmonized product that integrates the best remotely sensed estimates of landcover-specific C density. Water bodies identified as class “210” of the CCI 2010 landcover map were then masked from our final products.Data layers (n = 4, Table 7) for the maps of AGBC and BGBC density (Fig. 4) as well as their associated uncertainty maps which represent the combined standard error of prediction (Fig. 5) are available as individual 16-bit integer rasters in GeoTiff format. All layers are natively in a WGS84 Mercator projection with a spatial resolution of approximately 300 m at the equator and match that of the ESA CCI Landcover Maps37. Raster values are in units megagrams C per hectare (MgC ha−1) and have been scaled by a factor of ten to reduce file size. These data are accessible through the Oak Ridge National Laboratory (ORNL) DAAC data repository (https://doi.org/10.3334/ORNLDAAC/1763)66. In addition, updated and/or derived vegetation-specific layers that were used to create our harmonized 2010 maps are available as supplemental data on figshare67.Globally harmonized maps of above and belowground living biomass carbon densities. (a) Aboveground biomass carbon density (AGBC) and (b) belowground biomass carbon density (BGBC) are shown separately. Maps have been aggregated to a 5 km spatial resolution and reprojected here for visualization.Uncertainty of grid cell level above and belowground biomass carbon density estimates. Uncertainty is shown here as the coefficient of variation (%; standard error layer divided by mean estimate layer) of estimated AGBC (a) and BGBC (b) densities after harmonization. Maps have been aggregated to a 5 km spatial resolution and projected for visualization.Our harmonized products rely almost exclusively upon maps and models that have been rigorously validated by their original producers and were often accompanied by constrained uncertainty estimates. Throughout our harmonization procedure, we strived to conserve the validity of each of these products by minimizing the introduction of additional error and by tracking any introductions, as described above, such that the final error layers represent the cumulative uncertainty of the inputs used. Ground truth AGB and BGB data are almost always collected for individual landcover types. Consequently, we are unable to directly assess the validity of our integrated estimates beyond their relationships to individual landcover-specific estimates and the extents to which they were modified from their original, previously-validated form prior to and during our harmonization procedure.Temporal and spatial updates made to existing landcover-specific maps of non-tree AGB resulted in relatively small changes to their predictions. For example, we used numerically calibrated MODIS imagery to extend the Landsat-based tundra plant AGB model beyond its native extent (the North Slope of Alaska) to the pan-Arctic region since neither a comparable model nor a consistent Landsat time series were available for this extent. We assessed the effects of these assumptions by comparing our predictions for the North Slope with those of the original map18 (Fig. 6a). Both positive and negative discrepancies exist between ours and the original, though these rarely exceed ±2 MgC ha−1 and no discernibly systematic bias was evident.Differences between landcover-specific AGBC estimates from the original published maps and the modified versions used as inputs to create the 2010 harmonized global maps. Tundra vegetation AGBC (a) is compared to the Landsat-based map of Berner et al.45 for the north slope of Alaska after converting it to units MgC ha−1. Here, the comparison map was subsequently aggregated to a 1 km resolution and reprojected for visualization. Grassland AGBC (b) is compared to the AVHRR-based map of Xia et al.19 which represents the average estimate between 1982–2006. For visualization, the map was aggregated to a 5 km resolution and subsequently reprojected after being masked to MODIS IGBP grasslands in the year 200685 following Xia et al.19. As such, this map does not necessarily represent the spatial distribution of grid cells in which grassland estimates were used. Cropland AGBC (c) is compared to the original circa 2000 estimates to assess the effects of the 2000-to-2010 correction. The map is masked to the native extent of the combined yield maps and aggregated to a 5 km resolution for visualization. For all maps, negative values indicate that our circa 2010 estimates are lower than those of the earlier maps while positive values indicate higher estimates.Our updated map of grassland biomass carbon in the year 2010 was similarly made by applying the original AVHRR-based model to calibrated MODIS imagery. This too resulted in only subtle changes to the original biomass map (Fig. 6b) that were rarely in excess of 0.5 MgC ha−1. In most areas, our estimates were higher than those of Xia et al.19 who mapped the mean AGBC density between 1986 and 2006. Most of these elevated estimates corresponded with areas in which significant NDVI increases (“greening”) have been reported while notably lower estimates in the Argentine Monte and Patagonian steppe biomes of southern South America, likewise, correspond with areas of reported “browning”68,69. Both greening and browning trends are well documented phenomena and have been linked to climatic changes70. Moreover, we further compared AGBC estimates from both the original Xia et al.19 map and our 2010 update to AGBC field measurements coordinated by the Nutrient Network that were collected from 48 sites around the world between 2007 and 200949. The RMSE (0.68 MgC ha−1) of our updated map was 10% less that of the Xia et al. map for sites with less than 40% tree cover. Likewise, our 2010 estimates were virtually unbiased (bias = −0.01 MgC ha−1) in comparison to the Xia map (bias = 0.25 MgC ha−1). While still noisy, these results suggest that our temporal update improved the overall accuracy of estimated grassland AGBC.Finally, cropland biomass carbon maps were also updated from their native epoch (2000) to 2010 using pixel-wise rates of MODIS ANPP change over a ten-year period. While MODIS ANPP may be a poor snapshot of crop biomass in a single year, we assumed that its relative change over time reflects real physiological shifts affecting the cropland C cycle. This correction also resulted in only small differences that rarely exceeded ±2 MgC ha−1 and that, spatially, correspond well with observed declines in the yields of select crops that have been linked to climate change71,72 (Fig. 6c). Nonetheless, updated global yield maps comparable to those available for 2000 would greatly improve our understanding of the interactions between climate change, crop yields, and C dynamics.Belowground biomass is notoriously difficult to measure, model, and also to validate. We accounted for the reported uncertainty of nearly every variable considered when estimating belowground biomass and pixel-level uncertainty, but we were unable to perform an independent validation of our harmonized estimates at the pixel level due to a paucity of globally consistent field data. To complete such a task, a globally orchestrated effort to collect more BGB samples data across all vegetation types is needed.Given this lack of data, we instead compared the estimated uncertainty of our BGBC maps to that of our AGBC estimates to infer the sources of any divergence (Fig. 5). As expected, our cumulative BGBC uncertainty layer generally reveals greater overall uncertainty than our AGBC estimates, with BGBC uncertainty roughly twice that of AGBC throughout most of the globe. The highest absolute uncertainty was found in biomass rich forests. Arid woodlands, especially those of the Sahel and eastern Namibia, generally had the greatest relative BGBC uncertainty, though their absolute uncertainty was quite small (generally less than 3 MgC ha−1). Here, biomass estimates of sparse woody vegetation were primarily responsible for heightened relative uncertainty. High relative and absolute BGBC uncertainty were also associated with predictions in select mountainous forests (e.g. east central Chile) as well as forested areas in and around cities. These patterns were largely driven by AGB uncertainty in the GlobBiomass product.The GlobBiomass global woody AGB map produced by Santoro et al.30 comprises the backbone of our integrated products and, with few exceptions, remains largely unchanged in our final AGBC map. The native version of the GlobBiomass map is accompanied by an error layer describing the uncertainty of each pixel’s biomass estimate and this too forms the core of our integrated uncertainty layers. In areas with tree cover, the global average error of GlobBiomass estimates is 39 Mg ha−1 or 50% with greater relative uncertainty in densely forested areas, along the margins of forested expanses like farm fields and cities, and in similar areas with sparse tree cover.Adding additional grass or crop biomass in complementary proportion to a grid cell’s tree cover often did not exceed the estimated error of the original GlobBiomass map (Fig. 7). Grid cells exceeding GlobBiomass’s native uncertainty comprise less than 40% of its total extent. Exceptions were primarily found in grassland and cropland dominated regions where tree cover was generally sparse, and, consequently, the herbaceous biomass contribution was relatively high. Even so, the absolute magnitude of these additions remains somewhat small (less than 2.3 MgC ha−1 for grassland and 15 MgC ha−1 for cropland).Differences between the final harmonized AGBC map and GlobBiomass AGBC. GlobBiomass AGB was aggregated to a 300 m spatial resolution and converted to C density prior to comparison. Negative values indicate areas where the new map reports lower values than GlobBiomass while positive value denote higher estimates.Larger deviations from GlobBiomass were also present in areas of both dryland Africa and the Arctic tundra biome, where we used independent layers to estimate woody biomass. In African drylands, GlobBiomass likely underestimates woody biomass by adopting the conservative FAO definition (DBH > 10 cm), which implicitly omits the relatively small trees and shrubs that are common to the region. The Bouvet map of Africa that we used to supplement these estimates is not bound by this constraint, was developed from region-specific data, and predicts substantially higher AGB density throughout much of its extent with comparatively high accuracy (RMSE = 17.1 Mg ha−1)35.GlobBiomass also included sporadic biomass estimates throughout much of the Arctic tundra biome. Trees are generally scarce throughout this biome, which is instead dominated by dwarf shrubs and herbaceous forbs and graminoids, so given GlobBiomass’s adherence to FAO guidelines, its predictions here may be spurious. We thus prioritized the estimates of the independent model developed specifically to collectively predict biomass of both woody and herbaceous tundra vegetation. These estimates were generally higher than GlobBiomass but agreed well with independent validation data from North America (RMSE = 2.9 Mg ha−1)18.While far from a perfect comparison, the only other map to comprehensively report global biomass carbon density for all landcover types is the IPCC Tier-1 map for the year 2000 by Ruesch and Gibbs28. As previously described, this map was produced using an entirely different method (“stratify and multiply”) and distinct data sources23 and represents an earlier epoch. However, the map is widely used for myriad applications, and it may thus be informative to assess notable differences between it and our new products.Ruesch and Gibbs28 report total living C stocks of 345 petagrams (PgC) in AGBC and 133 PgC in BGBC for a total of 478 PgC, globally. Our estimates are lower at 287 PgC and 122 PgC in global AGBC and BGBC, respectively, for a total of 409 PgC in living global vegetation biomass. Herbaceous biomass in our maps comprised 9.1 and 28.3 PgC of total AGBC and BGBC, respectively. Half of all herbaceous AGBC (4.5 PgC) and roughly 6% of all herbaceous BGBC (1.7 PgC) was found in croplands. Moreover, we mapped 22.3 and 6.1 PgC, respectively, in the AGB and BGB of trees located within the cropland extent. These trees constituted roughly 7% of all global biomass C and are likely overlooked by both the Ruesch and Gibbs map28 and by remotely sensed forest C maps that are masked to forested areas. Zomer et al.17 first highlighted this potential discrepancy in the Ruesch and Gibbs map28 when they produced a remarkably similar estimate of 34.2 Pg of overlooked C in cropland trees using Tier-1 defaults. However, their estimates were assumed to be in addition to the 474 PgC originally mapped by Ruesch and Gibbs28. Here, we suggest that the 28.4 PgC we mapped in cropland trees is already factored into our 409 PgC total.Our AGBC product predicts substantially less biomass C than Ruesch and Gibbs28 throughout most of the pantropical region and, to a lesser extent, southern temperate forests (Fig. 8a). This pattern has been noted by others comparing the Ruesch and Gibbs map28 to other satellite-based biomass maps73 and may suggest that the IPCC default values used to create it23 are spatially biased. In addition, well-defined areas of high disagreement emerge in Africa that directly correspond with the FAO boundaries of the “tropical moist deciduous forest” ecofloristic zone and suggest that this area, in particular, may merit critical review. Moreover, the opposite pattern is observed in this same ecofloristic zone throughout South America. Our map also predicts greater AGBC throughout much of the boreal forest as well as in African shrublands and the steppes of South America.Differences between the 2010 harmonized global maps of above and belowground biomass carbon density and those of the IPCC Tier-1 product by Ruesch and Gibbs for 2000. Comparisons of AGBC (a) and BGBC (b) maps are shown separately. Negative values indicate that the circa 2010 estimates are comparatively lower while positive values indicate higher estimates.We observed similar, though less pronounced discrepancies, when comparing BGBC maps (Fig. 8b). Notably, our map predicts substantially more BGBC throughout the tundra biome – a previously underappreciated C stock that has recently risen to prominance74 – the boreal forest, African shrublands and most of South America and Australia. However, we predict less BGBC in nearly all rainforests (Temperate and Tropical). These differences and their distinct spatial patterns correspond with the vegetation strata used to make the IPCC Tier-1 map28 and suggest that the accuracy of the “stratify and multiply” method depends heavily upon the quality of the referenced and spatial data considered. Inaccuracies in these data may, in turn, lead to false geographies. Integrating, continuous spatial estimates that better capture local and regional variation, as we have done, may thus greatly improve our understanding of global carbon geographies and their role in the earth system.The error and variance between our woody biomass estimates – when aggregated to the country level – and comparable totals reported in the FRA were less for comparisons made against FRA estimates generated using higher tier IPCC methodologies than for those based on Tier-1 approaches (Fig. 9). Across the board for AGBC, BGBC, and total C comparisons, the relative RMSE (RMSECV) of our estimates, when compared to estimates generated using high tier methods, was roughly half of that obtained from comparisons with Tier-1 estimates (Table 8). Likewise, the coefficient of determination (R2) was greatest for comparisons with Tier-3 estimates. For each pool-specific comparison (AGBC, BGBC, and total C), the slopes of the relationships between Tier-1, 2, and 3 estimates were neither significantly different from a 1:1 relationship nor from one another (p > 0.05; ANCOVA). Combined, these results suggest that our maps lead to C stock estimates congruent with those attained from independent, higher-tier reporting methodologies.Comparison of woody biomass density estimates to corresponding estimates of the FAO’s FRA and the USFS’s FIA. National woody AGBC totals derived from the woody components of our harmonized maps are compared to national totals reported in the 2015 FRA62 (a) in relation to the IPCC inventory methodology used by each country. Likewise, we derived woody AGBC totals for US states and compared them to the corresponding totals reported by the 2014 FIA75 (b), a Tier-3 inventory. We also show the additional effect of considering non-woody C – as is reported in our harmonized maps – in light green. Similar comparisons were made between our woody BGBC estimates and the corresponding estimates of both the FRA (c) and FIA (d). We further summed our woody AGBC and BGBC estimates and compared them to the total woody C stocks reported by both the FRA (e) and FIA (f).To explore this association at a finer regional scale, we also compared our woody C estimates to the United States Forest Service’s Forest Inventory Analysis75 (FIA) and found similarly strong congruence for AGBC and Total C stocks but subtle overestimates for BGBC (Fig. 9). The FIA is a Tier-3 inventory of woody forest biomass C stocks that is based on extensive and statistically rigorous field sampling and subsequent upscaling, We used data available at the state level for the year 2014 – again, the only year in which we could obtain data partitioned by AGBC and BGBC. Like our FRA comparison, we found a tight relationship between our woody AGBC totals and those reported by the FIA (Fig. 9b; RMSECV = 25.7%, R2 = 0.960, slope = 1.10, n = 48). Our woody BGBC estimates, though, were systematically greater than those reported by the FIA (Fig. 9d; RMSECV = 86.4%, R2 = 0.95, slope = 1.51, n = 48). This trend has been noted by others27 and suggests that the global model that we used to estimate woody BGBC may not be appropriate for some finer scale applications as is foretold by the elevated uncertainty reported in our corresponding uncertainty layer (Fig. 5b). Our total woody C (AGBC + BGBC) estimates (Fig. 9f), however, agreed well with the FIA (RMSECV = 34.1%, R2 = 0.961, slope = 1.17, n = 48) and thus reflect the outsized contribution of AGBC to the total woody C stock. When the contribution of herbaceous C stocks is further added to these comparisons, our stock estimates intuitively increase in rough proportion to a state’s proportional extent of herbaceous cover. The effect of this addition is particularly pronounced for BGBC estimates due to the large root-to-shoot ratios of grassland vegetation.The relative congruence of our results with higher-tier stock estimates suggests that our maps could be used to facilitate broader adoption of higher-tier methods among countries currently lacking the requisite data and those seeking to better account for C in non-woody biomass. This congruence spans a comprehensive range of biophysical conditions and spatial scales ranging from small states to large nations. Moreover, a recent study suggests that the fidelity of the underlying GlobBiomass AGB map may extend to even finer scales31. While our BGBC estimates may differ from some fine-scale estimates (Fig. 9d), their tight agreement with high tier BGBC totals at the national level (Fig. 9c) suggests that they may still be well suited for many national-scale C inventories – especially for countries lacking requisite high tier data. Use of our maps is unlikely to introduce error in excess of that currently implicit in Tier-1 estimates. Credence, though, should be given to the associated uncertainty estimates. To facilitate wider adoption of higher-tier methodologies, our maps could be used to derive new, region-specific default values for use in Tier-2 frameworks76 or to either represent or calibrate 2010 baseline conditions in Tier-3 frameworks. In so doing, inventories and studies alike could more accurately account for the nuanced global geographies of biomass C.These maps are intended for global applications in which continuous spatial estimates of live AGBC and/or BGBC density are needed that span a broad range of vegetation types and/or require estimates circa 2010. They are loosely based upon and share the spatial resolution of the ESA CCI Landcover 2010 map37, which can be used to extract landcover specific C totals. However, our products notably do not account for C stored in non-living C pools like litter or coarse woody debris, nor soil organic matter, though these both represent large, additional ecosystem C stocks77,78,79. Our maps are explicitly intended for global scale applications seeking to consider C in the collective living biomass of multiple vegetation types. For global scale applications focused exclusively on the C stocks of a single vegetation type, we strongly encourage users to instead use the respective input map or model referenced in Table 1 to avoid potential errors that may have been introduced by our harmonization procedure. For AGB applications over smaller extents, users should further consider whether locally specific products are available. If such maps are not available and our maps are considered instead, credence should be given to their pixel-level uncertainty estimates. As mentioned above, the biomass of shrublands was only explicitly accounted for in Africa and the Arctic tundra, since neither broad-scale maps nor models generalizable to other areas were available in the existing literature. As such, we caution against the use of our maps outside of these areas when shrubland biomass is of particular interest or importance. Moreover, in contrast to the estimates for all other vegetation types considered, which we upscaled to a 300 m resolution, cropland C estimates were largely based on relatively coarse 8 km resolution data that were downscaled using bilinear resampling to achieve a 300 m spatial resolution. As such, these estimates may not adequately capture the underlying finer-scale spatial variation and should be interpreted with that in mind. Likewise, we reiterate that some BGBC estimates may differ from locally derived Tier-3 estimates, and attention should thus be given to our reported pixel-level uncertainty for all applications. Finally, our maps should not be used in comparison with the IPCC Tier-1 map of Ruesch and Gibbs (2008) to detect biomass change between the two study periods due to significant methodological differences between these products.Cropland biomass maps were created in the R statistical computing environment80. All other coding was done in Google Earth Engine81 (GEE), wherein our workflow consisted of 18 interconnected scripts. All code can be found on GitHub (https://github.com/sethspawn/globalBiomassC) and permanently archived by Zenodo82.Houghton, R. A., Hall, F. & Goetz, S. J. Importance of biomass in the global carbon cycle. J. Geophys. Res. Biogeosciences 114 (2009).Huntzinger, D. N. et al. The North American Carbon Program Multi-Scale Synthesis and Terrestrial Model Intercomparison Project – Part 1: Overview and experimental design. Geosci. Model Dev 6, 2121–2133 (2013).Article ADS Google Scholar Schwalm, C. R. et al. Toward “optimal” integration of terrestrial biosphere models. Geophys. Res. Lett. 42, 4418–4428 (2015).Article ADS Google Scholar Li, W. et al. Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations. Biogeosciences 14, 5053–5067 (2017).Article Google Scholar Spawn, S. A., Lark, T. J. & Gibbs, H. K. Carbon emissions from cropland expansion in the United States. Environ. Res. Lett. 14, 045009 (2019).Article CAS ADS Google Scholar Harris, N. L. et al. Baseline Map of Carbon Emissions from Deforestation in Tropical Regions. Science 336, 1573–1576 (2012).Article CAS PubMed ADS Google Scholar Baccini, A. et al. Tropical forests are a net carbon source based on aboveground measurements of gain and loss. Science 358, 230–234 (2017).Article MathSciNet CAS PubMed MATH ADS Google Scholar Strassburg, B. B. N. et al. Global congruence of carbon storage and biodiversity in terrestrial ecosystems. Conserv. Lett 3, 98–105 (2010).Article Google Scholar West, P. C. et al. Trading carbon for food: Global comparison of carbon stocks vs. crop yields on agricultural land. Proc. Natl. Acad. Sci. 107, 19645–19648 (2010).Article CAS PubMed ADS PubMed Central Google Scholar Carvalhais, N. et al. Global covariation of carbon turnover times with climate in terrestrial ecosystems. Nature 514, 213–217 (2014).Article CAS PubMed ADS Google Scholar Brandão, A. et al. Estimating the Potential for Conservation and Farming in the Amazon and Cerrado under Four Policy Scenarios. Sustainability 12, 1277 (2020).Article Google Scholar Gibbs, H. K., Brown, S., Niles, J. O. & Foley, J. A. Monitoring and estimating tropical forest carbon stocks: making REDD a reality. Environ. Res. Lett. 2, 045023 (2007).Article ADS CAS Google Scholar Fargione, J. E. et al. Natural climate solutions for the United States. Sci. Adv. 4, eaat1869 (2018).Article PubMed PubMed Central ADS Google Scholar Griscom, B. W. et al. Natural climate solutions. Proc. Natl. Acad. Sci. 114, 11645–11650 (2017).Article CAS PubMed ADS PubMed Central Google Scholar Goetz, S. J. et al. Mapping and monitoring carbon stocks with satellite observations: a comparison of methods. Carbon Balance Manag 4, 2 (2009).Article PubMed PubMed Central CAS Google Scholar Xiao, J. et al. Remote sensing of the terrestrial carbon cycle: A review of advances over 50 years. Remote Sens. Environ. 233, 111383 (2019).Article ADS Google Scholar Zomer, R. J. et al. Global Tree Cover and Biomass Carbon on Agricultural Land: The contribution of agroforestry to global and national carbon budgets. Sci. Rep 6, 29987 (2016).Article CAS PubMed PubMed Central ADS Google Scholar Berner, L. T., Jantz, P., Tape, K. D. & Goetz, S. J. Tundra plant above-ground biomass and shrub dominance mapped across the North Slope of Alaska. Environ. Res. Lett. 13, 035002 (2018).Article ADS Google Scholar Xia, J. et al. Spatio-Temporal Patterns and Climate Variables Controlling of Biomass Carbon Stock of Global Grassland Ecosystems from 1982 to 2006. Remote Sens 6, 1783–1802 (2014).Article ADS Google Scholar Monfreda, C., Ramankutty, N. & Foley, J. A. Farming the planet: 2. Geographic distribution of crop areas, yields, physiological types, and net primary production in the year 2000. Glob. Biogeochem. Cycles 22, GB1022 (2008).Article ADS CAS Google Scholar Wolf, J. et al. Biogenic carbon fluxes from global agricultural production and consumption. Glob. Biogeochem. Cycles 29, 1617–1639 (2015).Article CAS ADS Google Scholar Mokany, K., Raison, R. J. & Prokushkin, A. S. Critical analysis of root: shoot ratios in terrestrial biomes. Glob. Change Biol. 12, 84–96 (2006).Article ADS Google Scholar IPCC 2006. 2006 IPCC Guidelines for National Greenhouse Gas Inventories. vol. 4 (IPCC National Greenhouse Gas Inventories Programme, 2006).IPCC 2019. 2019 Refinement to the 2006 IPCC Guidlines for National Greenhouse Gas Inventories. vol. 4 (IPCC National Greenhouse Gas Inventories Programme, 2019).Reich, P. B. et al. Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots. Proc. Natl. Acad. Sci. 111, 13721–13726 (2014).Article CAS PubMed ADS PubMed Central Google Scholar Wang, P. et al. Belowground plant biomass allocation in tundra ecosystems and its relationship with temperature. Environ. Res. Lett. 11, 055003 (2016).Article ADS CAS Google Scholar Russell, M. B., Domke, G. M., Woodall, C. W. & D’Amato, A. W. Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States. Carbon Balance Manag 10, 20 (2015).Article PubMed PubMed Central CAS Google Scholar Ruesch, A. & Gibbs, H. New IPCC Tier-1 Global Biomass Carbon Map for the Year 2000. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, http://cdiac.ess-dive.lbl.gov (2008).Schimel, D. et al. Observing terrestrial ecosystems and the carbon cycle from space. Glob. Change Biol. 21, 1762–1776 (2015).Article ADS Google Scholar Santoro, M. et al. GlobBiomass - global datasets of forest biomass. PANGAEA https://doi.org/10.1594/PANGAEA.894711 (2018).Huang, W. et al. High-Resolution Mapping of Aboveground Biomass for Forest Carbon Monitoring System in the 3 Tri-State Region of Maryland, Pennsylvania and Delaware, USA. Environ. Res. Lett. 14, 095002 (2019).Article ADS Google Scholar Food and Agricultural Organization. FRA 2015 Terms and Definitions. (Food and Agricultural Organization of the United Nations, 2012).Quegan, S. et al. DUE GlobBiomass: D6 - Global Biomass Map Algorithm Theoretical Basis Document. GlobBiomass, http://globbiomass.org/wp-content/uploads/DOC/Deliverables/D6_D7/GlobBiomass_D6_7_Global_ATBD_v2.pdf (2017).Hansen, M. C. et al. High-Resolution Global Maps of 21st-Century Forest Cover Change. Science 342, 850–853 (2013).Article CAS PubMed ADS Google Scholar Bouvet, A. et al. An above-ground biomass map of African savannahs and woodlands at 25 m resolution derived from ALOS PALSAR. Remote Sens. Environ. 206, 156–173 (2018).Article ADS Google Scholar Le Toan, T., Beaudoin, A., Riom, J. & Guyon, D. Relating forest biomass to SAR data. IEEE Trans. Geosci. Remote Sens 30, 403–411 (1992).Article ADS Google Scholar European Space Agency. 300 m Annual global land cover time series from 1992 to 2015. European Space Agency - Climate Change Initiative, http://maps.elie.ucl.ac.be/CCI/viewer/download.php (2017).Bartholomé, E. & Belward, A. S. GLC2000: a new approach to global land cover mapping from Earth observation data. Int. J. Remote Sens. 26, 1959–1977 (2005).Article ADS Google Scholar Avitabile, V. et al. An integrated pan-tropical biomass map using multiple reference datasets. Glob. Change Biol. 22, 1406–1420 (2016).Article ADS Google Scholar Englund, O. et al. A new high-resolution nationwide aboveground carbon map for Brazil. Geo Geogr. Environ. 4, e00045 (2017).Article Google Scholar Scholze, M., Buchwitz, M., Dorigo, W., Guanter, L. & Quegan, S. Reviews and syntheses: Systematic Earth observations for use in terrestrial carbon cycle data assimilation systems. Biogeosciences 14, 3401–3429 (2017).Article CAS ADS Google Scholar Martin, A. R., Doraisami, M. & Thomas, S. C. Global patterns in wood carbon concentration across the world’s trees and forests. Nat. Geosci. 11, 915 (2018).Article CAS ADS Google Scholar Kottek, M., Grieser, J., Beck, C., Rudolf, B. & Rubel, F. World Map of the Köppen-Geiger climate classification updated. Meteorol. Z. 15, 259–263 (2006).Article Google Scholar Olofsson, P. et al. Good practices for estimating area and assessing accuracy of land change. Remote Sens. Environ. 148, 42–57 (2014).Article ADS Google Scholar Berner, L. T., Jantz, P., Tape, K. D. & Goetz, S. J. ABoVE: Gridded 30-m Aboveground Biomass, Shrub Dominance, North Slope, AK, 2007–2016. Oak Ridge National Laboratory Distributed Active Archive Center https://doi.org/10.3334/ORNLDAAC/1565 (2018).Vermote, E. F. & Wolfe, R. MYD09GQ MODIS/Aqua Surface Reflectance Daily L2G Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MYD09GQ.006 (2015).Vermote, E. F. & Wolfe, R. MOD09GQ MODIS/Terra Surface Reflectance Daily L2G Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MOD09GQ.006 (2015).Steven, M. D., Malthus, T. J., Baret, F., Xu, H. & Chopping, M. J. Intercalibration of vegetation indices from different sensor systems. Remote Sens. Environ. 88, 412–422 (2003).Article ADS Google Scholar Adler, P. B. et al. Productivity Is a Poor Predictor of Plant Species Richness. Science 333, 1750–1753 (2011).Article CAS PubMed ADS Google Scholar Didan, K. MYD13Q1 MODIS/Aqua Vegetation Indices 16-Day L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MYD13Q1.006 (2015).Didan, K. MOD13Q1 MODIS/Terra Vegetation Indices 16-Day L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center https://doi.org/10.5067/MODIS/MOD13Q1.006 (2015).Fensholt, R. & Proud, S. R. Evaluation of Earth Observation based global long term vegetation trends — Comparing GIMMS and MODIS global NDVI time series. Remote Sens. Environ. 119, 131–147 (2012).Article ADS Google Scholar Li, Z. et al. Comparing cropland net primary production estimates from inventory, a satellite-based model, and a process-based model in the Midwest of the United States. Ecol. Model. 277, 1–12 (2014).Article Google Scholar Turner, D. P. et al. Evaluation of MODIS NPP and GPP products across multiple biomes. Remote Sens. Environ. 102, 282–292 (2006).Article ADS Google Scholar Ramankutty, N., Evan, A. T., Monfreda, C. & Foley, J. A. Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000. Glob. Biogeochem. Cycles 22, GB1003 (2008).Grassini, P., Eskridge, K. M. & Cassman, K. G. Distinguishing between yield advances and yield plateaus in historical crop production trends. Nat. Commun. 4, 2918 (2013).Article PubMed ADS CAS Google Scholar Gray, J. M. et al. Direct human influence on atmospheric CO2 seasonality from increased cropland productivity. Nature 515, 398–401 (2014).Article CAS PubMed ADS Google Scholar Running, S. W., Mu, Q. & Zhao, M. MOD17A3H MODIS/Terra Net Primary Production Yearly L4 Global 1 km SIN Grid V055. NASA EOSDIS Land Processes Distributed Active Archive Center, https://lpdaac.usgs.gov/products/mod17a3v055/ (2015).Fick, S. & Hijmans, R. WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas. Int. J. Climatol. 37, 4302–4315 (2017).Article Google Scholar Potapov, P. et al. The last frontiers of wilderness: Tracking loss of intact forest landscapes from 2000 to 2013. Sci. Adv. 3, e1600821 (2017).Article PubMed PubMed Central ADS Google Scholar Harris, N. L., Goldman, E. D. & Gibbes, S. Spatial Database of Planted Trees (SDPT Version 1.0). World Resources Institute, https://www.wri.org/publication/planted-trees (2019).Food and Agricultural Organization. Global Forest Resources Assessment 2015: Desk Reference. (Food and Agricultural Organization of the United Nations, 2015).Dimiceli, C. et al. MOD44B MODIS/Terra Vegetation Continuous Fields Yearly L3 Global 250 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MOD44B.006 (2015).Sexton, J. O. et al. Global, 30-m resolution continuous fields of tree cover: Landsat-based rescaling of MODIS vegetation continuous fields with lidar-based estimates of error. Int. J. Digit. Earth 6, 427–448 (2013).Article ADS Google Scholar Dinerstein, E. et al. An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm. BioScience 67, 534–545 (2017).Article PubMed PubMed Central Google Scholar Spawn, S. A. & Gibbs, H. K. Global Aboveground and Belowground Biomass Carbon Density Maps for the Year 2010. Oak Ridge National Laboratory Distributed Active Archive Center, https://doi.org/10.3334/ORNLDAAC/1763 (2019).Spawn, S. A., Sullivan, C. C., Lark, T. J. & Gibbs, H. K. Harmonized global maps of above and belowground biomass carbon density in the year 2010. figshare https://doi.org/10.6084/m9.figshare.c.4561940 (2020).Gao, Q. et al. Climatic change controls productivity variation in global grasslands. Sci. Rep 6, 26958 (2016).Article CAS PubMed PubMed Central ADS Google Scholar de Jong, R., Verbesselt, J., Schaepman, M. E. & de Bruin, S. Trend changes in global greening and browning: contribution of short-term trends to longer-term change. Glob. Change Biol 18, 642–655 (2012).Article ADS Google Scholar Gonsamo, A., Chen, J. M. & Lombardozzi, D. Global vegetation productivity response to climatic oscillations during the satellite era. Glob. Change Biol. 22, 3414–3426 (2016).Article ADS Google Scholar Ray, D. K. et al. Climate change has likely already affected global food production. Plos One 14, e0217148 (2019).Article CAS PubMed PubMed Central Google Scholar Lobell, D. B., Schlenker, W. & Costa-Roberts, J. Climate Trends and Global Crop Production Since 1980. Science 333, 616–620 (2011).Article CAS PubMed ADS Google Scholar Hu, T. et al. Mapping Global Forest Aboveground Biomass with Spaceborne LiDAR, Optical Imagery, and Forest Inventory Data. Remote Sens 8, 565 (2016).Article ADS Google Scholar Iversen, C. M. et al. The unseen iceberg: plant roots in arctic tundra. New Phytol. 205, 34–58 (2015).Article PubMed Google Scholar USDA Forest Service. Forest Inventory and Analysis National Program: Standard Tables of Forest Caron Stock Estimates by State. Forest Inventory and Analysis National Program, https://www.fia.fs.fed.us/forestcarbon/index.php (2014).Langner, A., Achard, F. & Grassi, G. Can recent pan-tropical biomass maps be used to derive alternative Tier 1 values for reporting REDD + activities under UNFCCC? Environ. Res. Lett. 9, 124008 (2014).Article ADS Google Scholar Jobbágy, E. G. & Jackson, R. B. The Vertical Distribution of Soil Organic Carbon and Its Relation to Climate and Vegetation. Ecol. Appl. 10, 423–436 (2000).Article Google Scholar Scharlemann, J. P., Tanner, E. V., Hiederer, R. & Kapos, V. Global soil carbon: understanding and managing the largest terrestrial carbon pool. Carbon Manag 5, 81–91 (2014).Article CAS Google Scholar Domke, G. M., Woodall, C. W., Walters, B. F. & Smith, J. E. From Models to Measurements: Comparing Downed Dead Wood Carbon Stock Estimates in the U.S. Forest Inventory. Plos One 8, e59949 (2013).Article CAS PubMed PubMed Central ADS Google Scholar R Core Team. R: A Language and Environment for Statistical Computing, https://www.R-project.org/ (2017).Gorelick, N. et al. Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sens. Environ. 202, 18–27 (2017).Article ADS Google Scholar Spawn, S. A. sethspawn/globalBiomassC. Zenodo https://doi.org/10.5281/zenodo.3647567 (2020).Olson, D. M. et al. Terrestrial Ecoregions of the World: A New Map of Life on EarthA new global map of terrestrial ecoregions provides an innovative tool for conserving biodiversity. BioScience 51, 933–938 (2001).European Space Agency. Land Cover CCI Product User Guide Version 2, D3.4-PUG, v2.5. European Space Agency - Climate Change Initiative, http://maps.elie.ucl.ac.be/CCI/viewer/download/ESACCI-LC-PUG-v2.5.pdf (2016).Friedl, M. A. & Sulla-Menashe, D. MCD12Q1 MODIS/Terra + Aqua Land Cover Type Yearly L3 Global 500 m SIN Grid V006. NASA EOSDIS Land Processes Distributed Active Archive Center, https://doi.org/10.5067/MODIS/MCD12Q1.006 (2019).Jing, Q., Bélanger, G., Baron, V. & Bonesmo, H. Modeling the Biomass and Harvest Index Dynamics of Timothy. Agron. J. 103, 1397–1404 (2011).Article Google Scholar West, T. O. et al. Cropland carbon fluxes in the United States: increasing geospatial resolution of inventory-based carbon accounting. Ecol. Appl. 20, 1074–1086 (2010).Article PubMed Google Scholar Unkovich, M., Baldock, J. & Forbes, M. Variability in harvest index of grain crops and potential significance for carbon accounting: examples from Australian agriculture. Adv. Agron 105, 173–219 (2010).Article Google Scholar Hay, R. K. M. Harvest index: a review of its use in plant breeding and crop physiology. Ann. Appl. Biol. 126, 197–216 (1995).Article Google Scholar Larcher, W. Physiological Plant Ecology: Ecophysiology and Stress Physiology of Functional Groups. (Springer-Verlag, 2003).Hakala, K., Keskitalo, M. & Eriksson, C. Nutrient uptake and biomass accumulation for eleven different field crops. Agric. Food Sci 18, 366–387 (2009).Article CAS Google Scholar Bolinder, M. A., Janzen, H. H., Gregorich, E. G., Angers, D. A. & VandenBygaart, A. J. An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada. Agric. Ecosyst. Environ 118, 29–42 (2007).Article Google Scholar Mackenzie, B. A. & Van Fossen, L. Managing Dry Grain In Storage. In Agricultural Engineers’ Digest vol. 20 (Purdue University Cooperative Extension Service, 1995).Goodwin, M. Crop Profile for Dry Bean in Canada. Agriculture and Agri-Food Canada, http://publications.gc.ca/collections/collection_2009/agr/A118-10-4-2005E.pdf (2005).Schulte auf’m Erley, G., Kaul, H.-P., Kruse, M. & Aufhammer, W. Yield and nitrogen utilization efficiency of the pseudocereals amaranth, quinoa, and buckwheat under differing nitrogen fertilization. Eur. J. Agron. 22, 95–100 (2005).Article CAS Google Scholar Bjorkman, T. Northeast Buckwheat Growers Newsletter No. 19. Cornell University NYSAES, http://www.hort.cornell.edu/bjorkman/lab/buck/NL/june05.php (2005).Kyle, G. P. et al. GCAM 3.0 Agriculture and Land Use: Data Sources and Methods, https://doi.org/10.2172/1036082 (2011).Bastin, S. & Henken, K. Water Content of Fruits and Vegetables. University of Kentucky Cooperative Extension Service, https://www.academia.edu/5729963/Water_Content_of_Fruits_and_Vegetables (1997).Smil, V. Crop Residues: Agriculture’s Largest HarvestCrop residues incorporate more than half of the world’s agricultural phytomass. BioScience 49, 299–308 (1999).Article Google Scholar Squire, G. R. The physiology of tropical crop production. (C.A.B. International, 1990).Williams, J. R. et al. EPIC users guide v. 0509. Texas A & M University Blackland Research and Extension Center, http://epicapex.tamu.edu/files/2013/02/epic0509usermanualupdated.pdf (2006).Okeke, J. E. Cassava varietal improvement for processing and utilization in livestock feeds. In Cassava as Livestock Feed in Africa (International Institute of Tropical Agriculture, 1992).Pongsawatmanit, R., Thanasukarn, P. & Ikeda, S. Effect of Sucrose on RVA Viscosity Parameters, Water Activity and Freezable Water Fraction of Cassava Starch Suspensions. ScienceAsia 28, 129–134 (2002).Article CAS Google Scholar Gigou, J. et al. Fonio Millet (Digitaria Exilis) Response to N, P and K Fertilizers Under Varying Climatic Conditions in West. AFRICA. Exp. Agric 45, 401–415 (2009).Article Google Scholar Food and Agricultural Organization. FAOSTAT 2001: FAO statistical databasees. FAOSTAT, http://www.fao.org/faostat/en/#data (2006).Bolinder, M. A., Angers, D. A., Bélanger, G., Michaud, R. & Laverdière, M. R. Root biomass and shoot to root ratios of perennial forage crops in eastern Canada. Can. J. Plant Sci. 82, 731–737 (2002).Article Google Scholar Deferne, J. & Pate, D. W. Hemp seed oil: A source of valuable essential fatty acids. J. Int. Hemp Assoc 3, 4–7 (1996). Google Scholar Islam, Md. R. et al. Study of Harvest Index and Genetic Variability in White Jute (Corchorus capsularis) Germplasm. J. Biol. Sci. 2, 358–360 (2002).Article Google Scholar Ahad, A. & Debnath, C. N. Shoot Root Ratio of Jute Varieties and the Nature of Association Between Root Characteristics and the Yield of Dry Matter and Fiber. Bangladesh J. Agric. Res 13, 17–22 (1988). Google Scholar Mondal, S. S., Ghosh, A. & Debabrata, A. Effect of seeding time of linseed (Linum usitatissimum) in rice (Oryza sativa)-based paira cropping system under rainfed lowland condition. Indian J. Agric. Sci 75, 134–137 (2005). Google Scholar Ayaz, S., Moot, D. J., Mckenzie, B. A., Hill, G. D. & Mcneil, D. L. The Use of a Principal Axis Model to Examine Individual Plant Harvest Index in Four Grain Legumes. Ann. Bot. 94, 385–392 (2004).Article CAS PubMed PubMed Central Google Scholar Goudriaan, J. & Van Laar, H. H. Development and growth. In Modelling Potential Crop Growth Processes: Textbook with Exercises (eds. Goudriaan, J. & Van Laar, H. H.) 69–94 (Springer Netherlands, 1994).National Research Council. Nutrient Requirements of Nonhuman Primates: Second Revised Edition. (The National Academies Press, 2003).Roth, C. M., Shroyer, J. P. & Paulsen, G. M. Allelopathy of Sorghum on Wheat under Several Tillage Systems. Agron. J. 92, 855–860 (2000).Article Google Scholar Heidari Zooleh, H. et al. Effect of alternate irrigation on root-divided Foxtail Millet (Setaria italica). Aust. J. Crop Sci 5, 205–2013 (2011). Google Scholar Brück, H., Sattelmacher, B. & Payne, W. A. Varietal differences in shoot and rooting parameters of pearl millet on sandy soils in Niger. Plant Soil 251, 175–185 (2003).Article Google Scholar Oelke, E. A., Putnam, D. H., Teynor, T. M. & Oplinger, E. S. Quinoa. In Alternative Field Crops Manual (University of Wisconsin-Extension, Cooperative Extension, 1992).Robertson, M. J., Silim, S., Chauhan, Y. S. & Ranganathan, R. Predicting growth and development of pigeonpea: biomass accumulation and partitioning. Field Crops Res 70, 89–100 (2001).Article Google Scholar Armstrong, E. Desiccation & harvest of field peas. In Pulse management in Southern New South Wales (State of New South Wales Agriculture, 1999).Fischer, R. A. (Tony) & Edmeades, G. O. Breeding and Cereal Yield Progress. Crop Sci. 50, S-85–S-98 (2010).Article Google Scholar Atlin, G. N. et al. Developing rice cultivars for high-fertility upland systems in the Asian tropics. Field Crops Res 97, 43–52 (2006).Article Google Scholar Bueno, C. S. & Lafarge, T. Higher crop performance of rice hybrids than of elite inbreds in the tropics: 1. Hybrids accumulate more biomass during each phenological phase. Field Crops Res 112, 229–237 (2009).Article Google Scholar Yang, J. & Zhang, J. Crop management techniques to enhance harvest index in rice. J. Exp. Bot 61, 3177–3189 (2010).Article CAS PubMed Google Scholar Ziska, L. H., Namuco, O., Moya, T. & Quilang, J. Growth and Yield Response of Field-Grown Tropical Rice to Increasing Carbon Dioxide and Air Temperature. Agron. J. 89, 45–53 (1997).Article Google Scholar Mwaja, V. N., Masiunas, J. B. & Weston, L. A. Effects of fertility on biomass, phytotoxicity, and allelochemical content of cereal rye. J. Chem. Ecol. 21, 81–96 (1995).Article CAS PubMed Google Scholar Bruinsma, J. & Schuurman, J. J. The effect of spraying with DNOC (4,6-dinitro-o-cresol) on the growth of the roots and shoots of winter rye plants. Plant Soil 24, 309–316 (1966).Article CAS Google Scholar Yau, S. K., Sidahmed, M. & Haidar, M. Conservation versus Conventional Tillage on Performance of Three Different Crops. Agron. J. 102, 269–276 (2010).Article Google Scholar Hojati, M., Modarres-Sanavy, S. A. M., Karimi, M. & Ghanati, F. Responses of growth and antioxidant systems in Carthamustinctorius L. under water deficit stress. Acta Physiol. Plant. 33, 105–112 (2011).Article Google Scholar Oelke, E. A. et al. Safflower. In Alternative Field Crops Manual (University of Wisconsin-Extension, Cooperative Extension, 1992).Perez, R. Chapter 3: Sugar cane. In Feeding pigs in the tropics (Food and Agricultural Organization of the United Nations, 1997).Van Dillewijn, C. Botany of Sugarcane. (Chronica Botanica Co, 1952).Pate, F. M., Alvarez, J., Phillips, J. D. & Eiland, B. R. Sugarcane as a Cattle Feed: Production and Utilization. (University of Florida Extension Institute of Food and Agricultural Sciences, 2002).Download referencesWe gratefully acknowledge all the data producers, without whom this work would not be possible. We especially thank Maurizio Santoro et al., Alexandre Bouvet et al., Jiangzhou Xia et al., Logan T. Berner et al., Chad Monfreda et al., and Julie Wolf et al. whose AGB estimates comprise the core of our harmonized products and, in many cases, whose feedback greatly improved the quality of their inclusion. We are also grateful to the thoughtful feedback of three anonymous reviewers whose suggestions greatly improved the quality of our products and the clarity of our manuscript. Funding for this project was generously provided by the David and Lucile Packard Foundation and the National Wildlife Federation.Department of Geography, University of Wisconsin-Madison, Madison, WI, USASeth A. Spawn, Clare C. Sullivan & Holly K. GibbsCenter for Sustainability and the Global Environment (SAGE), Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, WI, USASeth A. Spawn, Clare C. Sullivan, Tyler J. Lark & Holly K. GibbsYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarYou can also search for this author in PubMed Google ScholarS.A.S. designed the harmonization procedure, compiled and standardized individual biomass layers, conducted all mapping, and led manuscript development. C.C.S., T.J.L. and H.K.G. assisted with conceptualization, and manuscript development.Correspondence to Seth A. Spawn.The authors declare no competing interests.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.The Creative Commons Public Domain Dedication waiver http://creativecommons.org/publicdomain/zero/1.0/ applies to the metadata files associated with this article.Reprints and PermissionsSpawn, S.A., Sullivan, C.C., Lark, T.J. et al. Harmonized global maps of above and belowground biomass carbon density in the year 2010. Sci Data 7, 112 (2020). https://doi.org/10.1038/s41597-020-0444-4Download citationReceived: 03 July 2019Accepted: 14 February 2020Published: 06 April 2020DOI: https://doi.org/10.1038/s41597-020-0444-4Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. 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Get information and guides to help you find and use NASA Earth science data, services, and tools.We provide a variety of ways for Earth scientists to collaborate with NASA.Making NASA's free and open Earth science data interactive, interoperable, and accessible for research and societal benefit both today and tomorrow.Changes in the land surface can impact climate, terrestrial ecosystems, and hydrology. Land surface-related data, including land cover type, land surface temperature, and topography, are critical for monitoring agricultural practices and water resource availability and for guiding interventions when necessary.Land surface reflectance is a measure of the fraction of incoming solar radiation reflected from Earth's surface to a satellite-borne or aircraft-borne sensor. These data are useful because they provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption, which is referred to as atmospheric correction.Land surface reflectance data can be used for visualizing the surface as well as for computing metrics and creating models that are useful for specific analysis. Agricultural production estimates must be restricted to crop-specific areas (e.g., corn, soybeans, etc.) to avoid confusion with other crops, natural vegetation, and areas of no vegetation. This allows specific crops to be observed over time using sustained land imaging and multi-spectral high-resolution imagery.An asterisk (*) next to an entry indicating that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) within three hours from satellite observation. Imagery is generally available 3-5 hours after observation. While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events.Sensor(s)/ Model NameObservation or Model500 m, 1 km, 5,600 m2017-present15 m, 30 m, 60 mOLI/OLI-2: 9 bands ranging from 0.43 µm to 1.38 µmETM+: 8 bands ranging from 0.45 µm to 12.5 µmTM: 7 bands ranging in wavelength from 0.45 µm to 2.35 µmOLI-2, OLI, ETM+, TMGeoTIFFOLI/OLI-2: 9 bands ranging from 0.43 µm to 1.38 µmMSI: 12 bands ranging from 0.443 µm to 2.190 µmThe Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument is a cooperative effort between NASA and Japan's Ministry of Economy, Trade and Industry (METI). ASTER Surface Reflectance data can be visualized and interactively explored using NASA Worldview:Research quality ASTER data products are available through Earthdata Search:Back to the TableThe Enhanced Thematic Mapper (ETM+), the Operational Land Imager (OLI) and OLI-2, and the Thermal Infrared Sensor-2 (TIRS-2) are aboard the joint NASA/USGS Landsat series of satellites.OLI data can be visualized and interactively explored using NASA Worldview:Research quality Landsat land surface reflectance data products can be accessed directly using USGS EarthExplorer:Back to the TableHarmonized Landsat Sentinel-2 (HLS) data provide consistent global observation of Earth’s surface reflectance and top-of-atmosphere (TOA) brightness data from the Landsat OLI and OLI-2 and the ESA (European Space Agency) Multi-Spectral Instrument (MSI) aboard the Sentinel-1A/B satellites every 2-3 days with 30 meter spatial resolution.HLS Surface Reflectance data can be visualized and interactively explored using NASA Worldview:Research quality HLS data products can be accessed directly from Earthdata Search:The Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) tool offers a simple and efficient way to access, transform, and visualize geospatial data from a variety of federal data archives, including USGS Landsat Analysis Ready Data (ARD) surface reflectance products. Back to the TableModerate Resolution Imaging Spectroradiometer (MODIS) Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption.MODIS Surface Reflectance data can be visualized and interactively explored using NASA Worldview:Multiple Geographic Information Systems (GIS) MODIS Surface Reflectance data layers with different band combinations are available through Esri’s ArcGIS OnLine (AGOL). NASA GIS data may be used with open-source GIS software such as Quantum GIS or Geographic Resources Analysis Support System (GRASS). Learn more about these tools in the Use the Data section below.Research quality MODIS data products can be accessed directly from Earthdata Search:Near real-time (NRT) MODIS Surface Reflectance data are available through NASA’s Land, Atmosphere Near real-time Capability for EOS (LANCE) within 60 to 125 minutes after a satellite observation:Back to the TableThe Visible Infrared Imaging Radiometer Suite (VIIRS) instrument is aboard the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) and NOAA-20 satellites. VIIRS/NPP Land Surface Reflectance Data from Earthdata Search Data are available daily and 8-day at various spatial resolutions.Near real-time (NRT) VIIRS Surface Reflectance data are available through LANCE within 60 to 125 minutes after a satellite observation:Back to the TableLand Surface Temperature (LST) describes processes such as the exchange of energy and water between the land surface and Earth's atmosphere. LST influences the rate and timing of plant growth and is affected by the albedo, or reflectance, of a surface. These data can improve decision-making for water use and irrigation strategies, and are also an indicator for crop health and water stress.An asterisk (*) next to an entry indicating that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) within three hours from satellite observation. Imagery is generally available 3-5 hours after observation. While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events.1 km, 0.05°0.25°, 0.5°, 1° GeoTIFFMODIS LST data can be visualized and interactively explored using NASA Worldview:MODIS LST data can be visualized in Giovanni:Research quality LST data products can be accessed directly from Earthdata Search and also are available through the Data Pool at NASA’s Land Processes DAAC (LP DAAC).The AppEEARS tool and MODIS subsetting tools can be used to quickly extract a subset of MODIS data for a region of interest.Near real-time (NRT) MODIS LST data are available through LANCE within 60 to 125 minutes after a satellite observation.Back to the TableResearch quality LST data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) are available in HDF-EOS format:Back to the TableA suite of MODIS LST and Emissivity (LST&E) products are available that combine MODIS data with ASTER data to leverage the strengths from both sensors. These integrated LST data can be visualized and interactively explored using NASA Worldview:Back to the TableThe ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission measures the temperature of plants to better understand how much water plants need and how they respond to stress.The AppEEARS tool and MODIS subsetting tools can be used to quickly extract a subset of ECOSTRESS data for a region of interest.Back to the TableThe Visible Infrared Imaging Radiometer Suite (VIIRS) instrument is aboard the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) and NOAA-20 satellites. Research quality LST data products from VIIRS: Near real-time (NRT) VIRS LST data are available through LANCE within 60 to 125 minutes after a satellite observation:Back to the TableLST data are produced as part of the NASA/USGS Landsat series of Earth observing missions.