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Yellow River Delta, China

Dec. 8, 2009
The Yellow River is the second-longest river in China, and the sixth longest in the world and makes many dramatic shifts over time. This image was taken with the ASTER instrument aboard NASA's Terra spacecraft in 2009.

The Yellow River is the second-longest river in China, and the sixth longest in the world. It drains a basin area of 740,000 square kilometers. It has been the cradle of Chinese civilization; but frequent devastating floods have also earned it the name of China's Sorrow. Historical maps from ~200BCE indicate the Yellow River was then flowing considerably north of its present course. A major course change in 1194 took over the Huai River drainage system throughout the next 700 years. The Yellow River adopted its present course in 1897 after the latest course change occurred in 1855. Currently, the Yellow River ends in the Bohai Sea, yet its eastern terminus continues to oscillate from points north and south of the Shandong Peninsula in its many dramatic shifts over time. The two ASTER images, acquired in 2001 (left) and 2009 (right), dramatically show the changes. The images cover an area of 36.5 x 41.4 km, and are located near 37.6 degrees north latitude, 119 degrees east longitude. Caption information from Wikipedia.

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 December 18, 1999, on NASA's Terra satellite. 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 the data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surfacemapping and monitoring of dynamic conditions and temporal change. Exampleapplications are: monitoring glacial advances and retreats; monitoringpotentially active volcanoes; identifying crop stress; determining cloudmorphology and physical properties; wetlands evaluation; thermal pollutionmonitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

The U.S. science team is located at JPL, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

More information about ASTER is available at http://asterweb.jpl.nasa.gov/.

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