As the U.S. Midwest continues to suffer from near-historic drought conditions, farmers in southwestern Kansas are among the hardest hit. According to the U.S. Department of Agriculture, the area is under "exceptional drought" conditions. This has led to significant reductions of the corn, soybean and pea crops. The two satellite images shown here, obtained about 10 years apart, clearly illustrate the effects of the drought. The top half of this image was acquired on Sept. 6, 2012 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft; the bottom half of the image was acquired by the Landsat Thematic Mapper on Sept. 15, 2002. Vegetation appears in red, and bare fields are gray or greenish in color. Both images cover an area of 9.3 by 27.9 miles (15 by 44.5 kilometers) and are located near 38.2 degrees north latitude, 100.8 degrees west longitude.
With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.
The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.
The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C.
More information about ASTER is available at http://asterweb.jpl.nasa.gov/.