Figure 1, March 30, 1989
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In the Al Jowf Province in northwestern Saudi Arabia, mining of fossil ground water has created an enormous agricultural enterprise, where tens of thousands of date palms and olive trees thrive in a hyper-arid environment. In a short 30-year period, the area has grown from 22 center-pivot irrigated fields to thousands. The Landsat TM image (Figure 1) was acquired March 30, 1989; the ASTER image on February 17, 2020. The images cover an area of 33.2 by 49 km, and are located at 30.1 degrees north, 38.3 degrees east.
With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of about 50 to 300 feet (15 to 90 meters), 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 in Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington.
More information about ASTER is available at http://asterweb.jpl.nasa.gov/.