# Presentation: 461624

## Mars Researchers Rendezvous on Remote Arctic Island 

**28 June 2001**

**Notes:**
Devon Island is situated in an isolated part of Canada's Nunavut Territory, and is usually considered to be the largest uninhabited island in the world. However, each summer since 1999, researchers from NASA's Haughton-Mars Project and the Mars Society reside at this "polar desert" location to study the geologic and environmental characteristics of a site which is considered to be an excellent "Mars analog": a terrestrial location wherein specific conditions approximate environmental features reported on Mars. Base camps established amidst the rocks and rubble surrounding the Haughton impact crater enable researchers to conduct surveys designed to test the habitat, equipment and technology that may be deployed during a human mission to Mars. One of the many objectives of the project scientists is to understand the ice formations around the Haughton area, in the hopes that this might ultimately assist with the recognition of areas where ice can be found at shallow depth on Mars.
These images of Devon Island from NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument provide contrasting views of the spectral and angular reflectance "signatures" of different surfaces within the region. The top panel is a natural color view created with data from the red, green and blue-bands of MISR's nadir (vertical-viewing) camera. The bottom panel is a false-color multiangular composite of the same area, utilizing red band data from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras, displayed as red, green and blue, respectively. In this representation, colors highlight textural properties of elements within the scene, with blue tones indicating smooth surfaces (which preferentially forward scatter sunlight) and red hues indicating rougher surfaces (which preferentially backscatter). The angular reflectance "signature" of low clouds causes them to appear purple, and this visualization provides a unique way of distinguishing clouds from snow and ice.
The data were captured on June 28, 2001, during the early part of the arctic summer, when sea ice becomes thinner and begins to move depending upon localized currents and winds. In winter the entire region is locked with several meters of nearly motionless sea ice, which acts as a thermodynamic barrier to the loss of heat from the comparatively warm ocean to the colder atmosphere. Summer melting of sea ice can be observed at the two large, dark regions of open water; one is present in the Jones Sound (near the top to the left of center), and another appears in the Wellington Channel (left-hand edge). A large crack caused by tidal heaving has broken the ice cover over the Parry Channel (lower right-hand corner). A substantial ice cap permanently occupies the easternmost third of the island (upper right). Surface features such as dendritic meltwater channels incised into the island's surface are apparent. The Haughton-Mars project site is located slightly to the left and above image center, in an area which appears with relatively little surface ice, near the island's inner "elbow".
The images were acquired during Terra orbit 8132 and cover an area of about 334 kilometers x 229 kilometers. They utilize data from blocks 27 to 31 within World Reference System-2 path 42.

## Where on Earth...? MISR Mystery Image Quiz #9

**Notes:**
Here's another chance to play geographical detective! These four images from the Multi-angle Imaging SpectroRadiometer MISR) cover the same geographic area but were acquired on four different dates. Each image was acquired by MISR's vertical-viewing (nadir) camera and encompasses an area measuring 257 kilometers x 195 kilometers. North is toward the top.
This mystery concerns a small island located near the western edge of the observed area. In the top two images, the island presents an obstacle to the westerly winds, and wake patterns in the cloud layers are visible downstream of the island's location. In the lower left image, the island is visible within a relatively clear area of open ocean. In the lower right image, the island is partially obscured by cumulus clouds, and a spiral cloud pattern associated with an atmospheric depression is visible in the southeast quadrant.
The Terra satellite, with MISR aboard, flies in a polar orbit and daylight images such as these are acquired as the spacecraft flies from north to south. Terra's orbit is "sun-synchronous", and when the satellite crosses the daylight equator the local time beneath the spacecraft is approximately 10:30 a.m. The four images shown here were processed identically, and relative variations in brightness between the different views have been preserved.
Using any reference materials you like, please answer the following 5 questions:
1. The images contain multiple clues that can be used to determine whether the observed area is situated in the northern or southern hemisphere. Name the hemisphere and describe at least two clues you used to establish your answer. (Clues should not make use of knowledge of the island's identity.)
2. Three of the following four statements about the island's environment are true. Which one is false? (A) Glaciers cover most of the island, and vegetation is limited to lichens and mosses.  (B) The island is of volcanic origin and located at the intersection of oceanic ridges. (C) A colony of Atlantic puffins makes the island its home. (D) The highest peak rises more than 750 meters above sea level.
3. Three of the following four statements about the history of the island are true. Which one is false? (A) Sovereignty over the island was transferred from one country to another sometime between 1918 and 1932.  (B) Steep cliffs make the island difficult to access, and despite many attempts the first landing did not take place until the 1850's. (C) In the 19th century, a whaling/sealing expedition christened the island with the name of a city located in their native country.  (D) The earliest documented discovery of the island was by an 18th century French explorer, and the island is currently named after this individual.
4. All five of the following events took place, but only four occurred during the second half of the 20th century. Which one did not occur in this time period? (A) The island and adjacent waters were designated a nature reserve. (B) A weather station was established on the island, providing automated temperature and pressure data. (C) A nuclear bomb test occurred within 3000 kilometers of the island. (D) An abandoned boat of unknown origin was discovered on the island. (E) The island's seals were declared to be protected species.
5. What is the name of the island and to which country does it belong?
Answers (added July 17, 2002)
The region shown is in the southern hemisphere. There are 5 clues which can be used to determine hemisphere: 
1.The clockwise rotation of the decaying cyclonic circulation in the lower right-hand panel; 
2.Brightness changes between the panels indicate that June is closer to mid-winter (June image appears darker than May image which is darker than April); 
3.Shadows from cumulus clouds (especially visible in the lower panels) are cast toward the south, thus the sun is north of the clouds; 
4.The northern sides of these clouds are more brightly illuminated than their southern sides, also indicating that the sun is to the north; 
5. Shadows are longer in June than in May. 
(Note: The westerly wind direction cannot be used as a reliable indicator of hemisphere, and westerlies can curve to the north or south in both hemispheres. Westerly winds do indicate that the region is probably at mid to high latitudes.)
The Atlantic Puffin (Fraterculus arctica) cannot be found here since the Puffin is restricted to the northern hemisphere. This small volcanic island is situated at the intersection of the Mid-Atlantic Ridge (southern extremity), the America-Antarctic Ridge, and the Atlantic Indian Ridge. Vegetation at this permanently glaciated isle is restricted to lichens and mosses. The highest peak (Olavtoppen) rises to 780 meters (2560 feet). 
The island was first sighted in 1738 by French explorer Jean-Baptiste Charles Bouvet de Lozier. Bouvet was convinced it was the northernmost tip of Antarctica but could not circumnavigate or land upon the island due to severe weather. Steep cliffs surrounding most sides of the island also made access difficult, and after various attempts, a landing was made in 1822 by an American sealer, Benjamin Morrell, who named the island after Bouvet. A British whaling/sealing expedition arrived three years later and named it Liverpool Island. The Norwegians claimed sovereignty of the island in 1928, and they renamed it in honor of Bouvet during their expedition of 1929.
Answer: E (see note below) (A) Bouvetøya became a Nature Reserve in 1971 (B) An automated weather station was established in 1977 (C) A nuclear bomb was detonated between Bouvetøya and Marion Island in 1979 (D) A lifeboat and supplies were discovered on the island in 1964, but their origin could not be determined. (E) Seals in the area were declared to be protected in 1935. However, this protection was incorporated into international agreement in 1959. *Respondents who noted this ambiguity were given credit for this question.
The island is Bouvet Island (or Bouvetøya) and is a territory of Norway.

## A Hazy Day in Mexico City

**Notes:**
Mexico City has one of the world's most serious air pollution problems. The city is located atop a high plain at an altitude of 200 meters, and is surrounded on three sides by mountains and snow-capped volcanoes. Since incident solar radiation does not vary significantly with season at tropical latitudes, photochemical smog is produced much of the year. In winter, air quality can worsen significantly when thermal inversions keep polluted air masses close to the surface.
Atmospheric particulates (aerosols) are readily visible at oblique view angles, and differences in aerosol amount on two days are indicated by these images of central Mexico from the Multi-angle Imaging SpectroRadiometer (MISR). The images at left and center are natural color views acquired by MISR's 70-degree forward-viewing camera on April 9 and December 5, 2001, respectively. Mexico City can be identified in the center panel by the large area of haze accumulation above image center. Two small brighter patches within the hazy area indicate low fog. In the left-hand panel, the city basin appears significantly clearer, but some haze remains apparent across the Sierra Madre mountains in the lower portion of the images. On the right is an elevation field corresponding to the December 5 view. Automated MISR stereoscopic retrievals reveal the clouds at lower right to be at very high altitudes, in contrast to the low-lying haze and fog near Mexico City. When the stereo retrieval determines that a location is not covered by clouds, digital terrain elevation data are displayed instead. High clouds appear as the orange and red areas, and mountainous areas appear light blue and green. The position of the clouds within the 70-degree image are slightly southward of their location in the elevation map as a consequence of geometric parallax.
Major sources of air pollutants within the basin enclosing the Mexico City urban area include exhaust from 3.5 million vehicles, thousands of industries, and mineral dust. The ancient lakebed valley in which Mexico City is situated became a major source of dust when it was drained in the 16th century. The city basin stretches approximately 70 kilometers wide; it is reported that the local air quality causes the surrounding mountains to be rarely visible from the urban center.
The Multi-angle Imaging SpectroRadiometer views almost the entire Earth every 9 days. These images were acquired during Terra orbits 6966 and 10461 and cover an area of 330 kilometers x 464 kilometers. They utilize data from blocks 75 to 77 within World Reference System-2 path 26.

## Distinguishing Clouds from Ice over the East Siberian Sea, Russia 

**Distinguishing Clouds from Ice over the East Siberian Sea, Russia **
**28 May 2002**

**Notes:**
As a consequence of its capability to retrieve cloud-top elevations, stereoscopic observations from the Multi-angle Imaging SpectroRadiometer (MISR) can discriminate clouds from snow and ice. The central portion of Russia's East Siberian Sea,  including one of the New Siberian Islands, Novaya Sibir, are portrayed in these views from data acquired on May 28, 2002.
The left-hand image is a natural color view from MISR's nadir camera. On the right is a height field retrieved using automated computer processing of data from multiple MISR cameras. Although both clouds and ice appear white in the natural color view, the stereoscopic retrievals are able to identify elevated clouds based on the geometric parallax which results when they are observed from different angles. Owing to their elevation above sea level, clouds are mapped as green and yellow areas, whereas land, sea ice, and very low clouds appear blue and purple. Purple, in particular, denotes elevations very close to sea level. The island of Novaya Sibir is located in the lower left of the images. It can be identified in the natural color view as the dark area surrounded by an expanse of fast ice. In the stereo map the island appears as a blue region indicating its elevation of less than 100 meters above sea level. Areas where the automated stereo processing failed due to lack of sufficient spatial contrast are shown in dark gray. The northern edge of the Siberian mainland can be found at the very bottom of the panels, and is located a little over 250 kilometers south of Novaya Sibir. Pack ice containing numerous fragmented ice floes surrounds the fast ice, and narrow areas of open ocean are visible.
The East Siberian Sea is part of the Arctic Ocean and is ice-covered most of the year. The New Siberian Islands are almost always covered by snow and ice, and tundra vegetation is very scant. Despite continuous sunlight from the end of April until the middle of August, the ice between the island and the mainland typically remains until August or September.
The Multi-angle Imaging SpectroRadiometer views almost the entire Earth every 9 days. These images were acquired during Terra orbit 12986 and cover an area of about 380 kilometers x 1117 kilometers. They utilize data from blocks 24 to 32 within World Reference System-2 path 117.

## Summer Harvest 

**in Saratov, Russia**
**31 May 2002**
**18 July 2002**

**Notes:**
Russia's Saratov Oblast (province) is located in the southeastern portion of the East-European plain, in the Lower Volga River Valley. Southern Russia produces roughly 40 percent of the country's total agricultural output, and Saratov Oblast is the largest producer of grain in the Volga region. Vegetation changes in the province's agricultural lands between spring and summer are apparent in these images acquired on May 31 and July 18, 2002 (upper and lower image panels, respectively) by the Multi-angle Imaging SpectroRadiometer (MISR).
The left-hand panels are natural color views acquired by MISR's vertical-viewing (nadir) camera. Less vegetation and more earth tones (indicative of bare soils) are apparent in the summer image (lower left). Farmers in the region utilize staggered sowing to help stabilize yields, and a number of different stages of crop maturity can be observed. The main crop is spring wheat, cultivated under non-irrigated conditions. A short growing season and relatively low and variable rainfall are the major limitations to production. Saratov city is apparent as the light gray pixels on the left (west) bank of the Volga River. Riparian vegetation along the Volga exhibits dark green hues, with some new growth appearing in summer.
The right-hand panels are multi-angle composites created with red band data from MISR's 60-degree backward, nadir and 60-degree forward-viewing cameras displayed as red, green and blue respectively. In these images, color variations serve as a proxy for changes in angular reflectance, and the spring and summer views were processed identically to preserve relative variations in brightness between the two dates. Urban areas and vegetation along the Volga banks look similar in the two seasonal multi-angle composites. The agricultural areas, on the other hand, look strikingly different. This can be attributed to differences in brightness and texture between bare soil and vegetated land. The chestnut-colored soils in this region are brighter in MISR's red band than the vegetation. Because plants have vertical structure, the oblique cameras observe a greater proportion of vegetation relative to the nadir camera, which sees more soil. In spring, therefore, the scene is brightest in the vertical view and thus appears with an overall greenish hue. In summer, the soil characteristics play a greater role in governing the appearance of the scene, and the angular reflectance is now brighter at the oblique view angles (displayed as red and blue), thus imparting a pink color to much of the farmland and a purple color to areas along the banks of several narrow rivers. The unusual appearance of the clouds is due to geometric parallax which splits the imagery into spatially separated components as a consequence of their elevation above the surface.
The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and views almost the entire globe every 9 days. These images are a portion of the data acquired during Terra orbits 13033 and 13732, and cover an area of about 173 kilometers x 171 kilometers. They utilize data from blocks 49 to 50 within World Reference System-2 path 170.