nasa-gesdisc/es-publications-researchareas huggingface dataset:
Revisiting the global hydrological cycle: is it intensifying? (2020)

Abstract. As a result of technological advances in monitoring atmosphere, hydrosphere, cryosphere and biosphere, as well as in data management and processing, several databases have become freely available. These can be exploited in revisiting the global hydrological cycle with the aim, on the one hand, to better quantify it and, on the other hand, to test the established climatological hypotheses according to which the hydrological cycle should be intensifying because of global warming. By processing the information from gridded ground observations, satellite data and reanalyses, it turns out that the established hypotheses are not confirmed. Instead of monotonic trends, there appear fluctuations from intensification to deintensification, and vice versa, with deintensification prevailing in the 21st century. The water balance on land and in the sea appears to be lower than the standard figures of literature, but with greater variability on climatic timescales, which is in accordance with HurstKolmogorov stochastic dynamics. The most obvious anthropogenic signal in the hydrological cycle appears to be the over-exploitation of groundwater, which has a visible effect on the rise in sea level. Melting of glaciers has an equal effect, but in this case it is not known which part is anthropogenic, as studies on polar regions attribute mass loss mostly to ice dynamics.

Research areas: Validation
Neighborhood greenness associated with chronic obstructive pulmonary disease: A nationwide cross-sectional study in China (2020)

Differential findings have been reported on the association between neighborhood greenness and chronic obstructive pulmonary disease (COPD). The underlying reasons might be the different types of vegetation and the diagnosis methods used in different studies. In this nationwide cross-sectional study in China, we examined the linkage between neighborhood greenness and COPD prevalence among 66,752 adults aged 40 years and above. Neighborhood greenness was estimated using the normalized difference vegetation index (NDVI) based on satellite imagery within buffers of 100, 300, 500, 1000, 2000, 3000 and 5000 m of residential community of the participants. COPD was defined according to the 2017 Global Initiative for Chronic Obstructive Lung Disease lung function criteria. A two-level logistic regression model was applied to estimate the associations. Finally, 9134 adults were classified as COPD. We observed significant positive associations between neighborhood greenness and COPD prevalence. The odds ratio for each interquartile range increase in NDVI within 100 m buffer was 1.08 (95% CI: 1.01, 1.15) after adjustment for potential confounders. Consistent associations were observed across all other NDVI buffer sizes. Stratified analyses revealed that younger adults (4065 years) and urban residents might be the vulnerable subpopulations. Further regional analyses found that residents from the Northeastern and Northern China were more likely to have this association. Our results indicated that neighborhood greenness might be one risk factor of COPD prevalence. Our study have important public health implications for allocating the surrounding green spaces among living areas, especially for those with respiratory illness; however, the findings and the underlying mechanisms warrant further examinations in longitudinal settings.

Research areas: Public Health
Increased Diurnal Activity Is Indicative of Energy Deficit in a Nocturnal Mammal, the Aardvark (2020)

Shifting activity to cooler times of day buffers animals from increased heat and aridity under climate change. Conversely, when resources are limited, some nocturnal species become more diurnal, reducing energetic costs of keeping warm at night. Aardvarks (Orycteropus afer) are nocturnal, obligate ant- and termite-eating mammals which may be threatened directly by increasing heat and aridity, or indirectly by the effects of climate change on their prey. We hypothesised that the minimum 24-h body temperature of aardvarks would decline during energy scarcity, and that aardvarks would extend their active phases to compensate for reduced resource availability, possibly resulting in increased diurnal activity when aardvarks were energetically compromised. To measure their thermoregulatory patterns and foraging activity, we implanted abdominal temperature and activity data loggers into twelve adult aardvarks and observed them for varying durations over three years in the Kalahari. Under non-drought conditions, aardvarks tightly controlled their 24-h body temperature rhythm (mean amplitude of the 24-h body temperature rhythm was 1.8  0.3 C during summer and 2.1  0.1 C during winter) and usually were nocturnal. During a summer drought, aardvarks relaxed the precision of body temperature regulation (mean 24-h amplitude 2.3  0.4 C) and those that subsequently died shifted their activity to progressively earlier times of day in the weeks before their deaths. Throughout the subsequent winter, the aardvarks minimum 24-h body temperatures declined, causing exaggerated heterothermy (4.7  1.3 C; absolute range 24.7 to 38.8 C), with one individuals body temperature varying by 11.7 C within 8 h. When body temperatures were low, aardvarks often emerged from burrows during daytime, and occasionally returned before sunset, resulting in completely diurnal activity. Aardvarks also shortened their active periods by 25 % during food scarcity, likely to avoid energetic costs incurred by foraging. Despite their physiological and behavioural flexibility, aardvarks were unable to compensate for reduced food availability. Seven study aardvarks and several others died, presumably from starvation. Our results do not bode well for aardvarks facing climate change, and for the many animal species dependent on aardvark burrows for refuge.

Research areas: Ecosystems
The effect of wind and temperature to phytoplankton biomass during blooming season in Barents Sea (2020)

The Barents Sea is the most productive sea in the Arctic. The main causes of phytoplankton spring blooms are studied for a decadal time period of 20032013 at the region of (70 N-80 N, 30 E-40 E) in Barents Sea. Due to the rapidly ice melt in the southern region (70 N-75 N), almost no ice left after year 2005, sea surface temperature (SST) and wind speed (WIND) are two main dominant factors influencing phytoplankton blooming in the southern region. Ice melt is another important factor of phytoplankton blooming in the northern region (75 N80 N). SST and CHL had positive correlations during blooming season but negative correlations during summer time. The lower SST in spring could result in earlier blooming in the region. Higher SST and higher WIND could result in later blooming. Positive NAO after April 2013 caused higher SST in 2013. Increasing WIND would cause CHL reduced accordingly. Blooming period is from late April to late May in the southern region, and 12 weeks later in the northern region. During blooming season, SST was less than 4 C and WIND was less than 10 m/s. The higher winds (over 15 m/s) in early spring would brought more nutrients from bottom to surface and cause higher blooming (near 10 mg/m3 in year 2010) after WIND is reduced to 58 m/s. Higher WIND (around 10 m/s) could generate longer blooming period (more than a week) during late May in the southern region. Decrease of WIND and increase of melting ice, with slightly increase of SST and decrease of mixed layer depth (MLD), are all the factors of phytoplankton blooming in late spring and early summer.

Research areas: Cryospheric Indicators, Ecosystems
The Southern Annular Mode (SAM) influences phytoplankton communities in the seasonal ice zone of the Southern Ocean (2020)

Abstract. Ozone depletion and climate change are causing the Southern Annular Mode (SAM) to become increasingly positive, driving stronger winds southward in the Southern Ocean (SO), with likely effects on phytoplankton habitat due to possible changes in ocean mixing, nutrient upwelling, and sea ice characteristics. This study examined the effect of the SAM and 12 other environmental variables on the abundance of siliceous and calcareous phytoplankton in the seasonal ice zone (SIZ) of the SO. A total of 52 surface-water samples were collected during repeat resupply voyages between Hobart, Australia, and Dumont d'Urville, Antarctica, centred around longitude 142 E, over 11 consecutive austral springsummer seasons (20022012), and spanning 131 d in the springsummer from 20 October to 28 February. A total of 22 taxa groups, comprised of individual species, groups of species, genera, or higher taxonomic groups, were analysed using CAP analysis (constrained analysis of principal coordinates), cluster analysis, and correlation. Overall, satellite-derived estimates of total chlorophyll and measured depletion of macronutrients both indicated a more positive SAM was associated with greater productivity in the SIZ. The greatest effect of the SAM on phytoplankton communities was the average value of the SAM across 57 d in the previous austral autumn centred around 11 March, which explained 13.3 % of the variance in community composition in the following springsummer. This autumn SAM index was significantly correlated pair-wise (p<0.05) with the relative abundance of 12 of the 22 taxa groups resolved. A more positive SAM favoured increases in the relative abundance of large Chaetoceros spp. that predominated later in the springsummer and reductions in small diatom taxa and siliceous and calcareous flagellates that predominated earlier in the springsummer. Individual species belonging to the abundant Fragilariopsis genera responded differently to the SAM, indicating the importance of species-level observation in detecting SAM-induced changes in phytoplankton communities. The day through the springsummer on which a sample was collected explained a significant and larger proportion (15.4 %) of the variance in the phytoplankton community composition than the SAM, yet this covariate was a proxy for such environmental factors as ice cover and sea surface temperature, factors that are regarded as drivers of the extreme seasonal variability in phytoplankton communities in Antarctic waters. The impacts of SAM on phytoplankton, which are the pasture of the SO and principal energy source for Antarctic life, would have ramifications for both carbon export and food availability for higher trophic levels in the SIZ of the SO.

Research areas: Atmospheric/Ocean Indicators, Ecosystems
SO2 and HCHO over the major cities of Kazakhstan from 2005 to 2016: influence of political, economic and industrial changes (2020)

Satellite observations of the Ozone Monitoring Instrument (OMI) for tropospheric sulfur dioxide (SO2) and formaldehyde (HCHO) column mass densities (CMD) are analyzed for the period 20052016 over the atmosphere of Kazakhstan. Regarding SO2 the major hot spots relate to regions with high population and large industrial facilities. Such an example is the city of Ekibastuz that hosts the biggest thermal power plants in the country and exhibits the higher SO2 CMD at national level. The annual average CMD in Ekibastuz reaches 2.5  105 kg/m2, whereas for the rest of the country respective values are 6 times lower. Other hotspots, mostly urban conglomerates such as Almaty and Nur-Sultan, experience high CMDs of SO2 in particular years, such as 2008. One of the main reasons for this behavior is the financial crisis of 2008, forcing the application of alternate heating sources based on cheap low-quality coal. Regarding HCHO, an oxygenated Volatile Organic Compound (VOC), the main hot spot is noticed over the city Atyrau, the oil capital of the country where two massive oil fields are located. The highest HCHO CMD (9  1015 molecules/cm2) appears in the summertime due to secondary production as a result of the photo-oxidation of VOCs emitted by industrial sectors, oil refinery plants and vehicles. Strongly elevated HCHO amounts are also observed in Nur-Sultan in 2012 that could be due to the residential coal combustion and vehicle exhaust under poor winter dispersion conditions. Significant reductions in HCHO observed between 2012 and 2015 can be attributed to two significant measures implemented in the country in 2013 that aimed at the improvement of air quality: the introduction of the emission trading system (ETS) for greenhouse gases and Euro-4 standards for new vehicles entering the national vehicle fleet.

Research areas: Air Quality, Energy Production/Use
Methane vertical profiles over the Indian subcontinent derived from the GOSAT/TANSO-FTS thermal infrared sensor (2020)

Abstract. We examined CH4 variability over different regions of India and the surrounding oceanic regions derived from thermal infrared (TIR) band observations by the Thermal And Near-infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observation SATellite (GOSAT) and simulated by the updated MIROC4.0-based Atmospheric Chemistry Tracer Model (MIROC4-ACTM) for the period 20092014. This study attempts to understand the sensitivity of the vertical profile retrievals at different layers of the troposphere and lower stratosphere, arising from the averaging kernels and a priori assumptions. We stress that this is of particular importance when the satellite derived products are analyzed using a different ACTMs from that is used as retrieval a priori. A comparison of modeled and retrieved CH4 vertical profiles shows the 22 vertical levels of GOSAT/TANSO-FTS TIR retrievals provide critical information about transport from the top of the boundary layer to the upper troposphere and lower stratosphere in a consistent manner. The mean model-GOSAT TIR CH4 mismatch is within 50 ppb, excepting 150 hPa and upward, where the sensitivity of GOSAT/TANSO-FTS TIR observations becomes very low. Convolution of the modeled profiles with GOSAT/TANSO-FTS TIR averaging kernels reduce the mismatch to below uncertainty. Distinct seasonal variations of CH4 have been observed at the upper atmospheric boundary layer (800 hPa), free troposphere (500 hPa), and upper troposphere (200 hPa) levels over northern and southern regions of India corresponding to the southwesterly monsoon (JulySeptember) and post-monsoon (OctoberDecember) seasons. Analysis of the transport and emission contributions to CH4 suggests that the CH4 seasonal cycle over the Indian subcontinent is governed by both the heterogeneous distributions of surface emissions and the influence of the global monsoon divergent wind circulations. GOSAT/TANSO-FTS TIR observations provide additional information about CH4 observations in this region compared to what is known from in situ data, which is important for improving the accuracy of emission flux optimization. Based on two emission sensitivity simulations, we suggest that the emissions of CH4 from the India region is 51.2  1.6 Tg yr1 during the period of 20092014.

Research areas: Greenhouse Gases
Trend analysis and first time observations of sulphur dioxide and nitrogen dioxide in South Africa using TROPOMI/Sentinel-5 P data (2020)

The 17 Sustainable Development Goals (SDGs) aim to end extreme poverty and create a healthy, sustainable world by the year 2030. Goal 7 is of interest to this study as it targets access to clean and affordable energy. However, in this study we show that the energy created in South Africa is not necessary clean. South Africa has numerous coal-fired power station located in the Mpumalanga (MP), Gauteng (GP) and Limpopo (LP) provinces. These power station produce tons of toxic pollutants including sulphur dioxide (SO2), nitrogen dioxide (NO2) and sulphates (SO4). These pollutants are known to have a negative impact on human health, climate and the environment. In this study we use the sequential Mann-Kendall test to investigate the 39 year (19802019) trends of SO2, NO2 and SO4 from these source areas. We also report for the first time on the observations of SO2 and NO2 from the Sentinel-5 P sensor over South Africa. Increasing trends of SO2 were observed in the MP, LP and GP regions. The increase was mostly due to the emissions from coal-fired power stations. Moreover, the increase of SO2 over the years could be due to the increasing demand in electricity, aging power stations and the low quality of coal used. Sentinel-5 P observations of SO2 and NO2 over South Africa were observed in the MP, GP and LP regions as a result of coal-fired power stations. Dispersion of SO2 and NO2 over South Africa were observed in the winter months, while confined SO2 and NO2 in the source region were observed in the summer months.

Research areas: Air Quality
Analysis of the atmospheric dust in Africa: The breathable dust's fine particulate matter PM2.5 in correlation with carbon monoxide (2020)

The dust has direct effects on people's health and climate change; so, this research studied the remotely sensed dust deposition in Africa from 1980 to 2018, and the dust's particulate matter of 2.5 m size (or PM2.5), in particular, which pollutes the breathable air. PM2.5 is studied in comparison with multispectral carbon monoxide (CO), an abundant atmospheric air pollutant in central Africa. CO is an atmospheric gaseous pollutant for which the smoke, a gaseous aerosol from incomplete combustion processes, is the biggest source. The literature clarifies that both the particulate matter and the CO endanger human health while breathed in. The dust from the desert of Sahara is windblown all over the world. CO, in Africa, is from the anthropogenic fire and volcanic eruptions' smoke; these are two good reasons to have focused on Africa. Due to the big size of Africa, five sub-regions are set; these are the western, central, northern, eastern and southern sub-regions. The Goddard interactive online visualization and analysis infrastructure (GIOVANNI) has been a bridge to the collected remote sensing data, in this research. The data was collected online, from the measurement of pollution in the troposphere (MOPITT) as well as a second version of the modern era retrospective analysis for research and applications (MERRA-2); the analysis was done by a joint of the software tools, worth noting is the Arc GIS. As the amount of African dust dramatically increased by 2000; the heaviest in 2004, results are based on the selected dust deposition over 20002018: time-averaged maps, correlations, and quantitative estimations are reported in this research. The heaviest annual dust deposition reached 25.3 t/km2 over the year 2004, in Liberia, a focal point of study for the western sub-region. An important finding: the dust's PM2.5 positively correlated with multispectral CO from November to May; the positively high correlation coefficient was 0.86 in April 2018. The negative correlation between the two measurements started from June to October; the negatively high correlation was 0.68 in October 2015; this research discussed the possible reasons. This research recommends some onsite studies about the real figures and facts about the dust's effects on health, in all the seasons; thus, an alert to policymakers who would set some strategies to mitigate the dust hazards on the health of African inhabitants, neighbors, and visitors.

Research areas: Air Quality
Impact of urban and industrial features on land surface temperature: Evidences from satellite thermal indices (2020)

Land surface transformations associated to the urbanization has impacted local climates and terrestrial surface energy processes. The occurrence of higher temperatures in urbanized areas when compared to rural and natural areas is called surface urban heat island (SUHI). The aim of this work was to investigate different remote sensing thermal indices and their impact in an urbanized and industrialized city in Southeast Brazil. This municipality constitutes an interesting case of middle-sized city, between two big cities, that might be currently undergoing unsustainable growth. Landsat satellite images were used to derive the thermal indices based on Land Surface Temperature (LST). The results showed that high LST values were concentrated in urban and industrial areas, with buildings, impermeable pavements and sparse vegetation. Urbanized and poorly vegetated areas showed high SUHI intensity. Vegetated areas had the best thermal comfort in town. Industries and parking lots were frequently classified as SUHI and were also considered as urban hot spots. The type of materials used in constructing these areas seems to be a reason for the higher temperatures. Further studies are needed in order to better understand the thermal conductivity of those materials and to plan how to reduce temperature in such areas.

Research areas: Heat, Habitat Conversion/Fragmentation
Coral microbiome composition along the northern Red Sea suggests high plasticity of bacterial and specificity of endosymbiotic dinoflagellate communities (2020)

The capacity of reef-building corals to tolerate (or adapt to) heat stress is a key factor determining their resilience to future climate change. Changes in coral microbiome composition (particularly for microalgal endosymbionts and bacteria) is a potential mechanism that may assist corals to thrive in warm waters. The northern Red Sea experiences extreme temperatures anomalies, yet corals in this area rarely bleach suggesting possible refugia to climate change. However, the coral microbiome composition, and how it relates to the capacity to thrive in warm waters in this region, is entirely unknown.

Research areas: Ecosystems, Atmospheric/Ocean Indicators
Strong upwelling conditions drive differences in species abundance and community composition along the Atlantic coasts of Morocco and Western Sahara (2020)

Upwelling strongly influences the composition and dynamics of coastal communities by affecting species abundances, recruitment, dispersal and distribution. Coastal upwelling areas are key model regions to study the responses of coastal species to climate change because they are characterized by cooler water conditions and experience lower warming rates than adjacent regions, making them effective control or refuge sites. This is particularly true for the benthic species of rocky shores in upwelling areas because they are sedentary, inhabit the interface between marine and terrestrial habitats, are exposed to extremely severe and variable environmental conditions and often live near their tolerance limits. We sampled roughly 2000 km of the Atlantic coast of Morocco and Western Sahara to assess the influence of upwelling cells on patterns of diversity and abundance of northern African rocky shore species. We recorded 186 taxa, providing clarification of the distribution of 141 algae and documenting nine new species records for Morocco and Western Sahara. The results emphasize the influence of upwelling on the abundance and distribution of these organisms. The contrast between non-upwelling and upwelling areas highlights the direct and indirect importance of water temperature in shaping these communities, pointing to the consequences of large-scale warming. Such warming is likely to threaten intertidal species that already live close to their thermal tolerance limits and are not buffered by the effects of upwelling.

Research areas: Atmospheric/Ocean Indicators, Ecosystems