Water level changes of two Tibetan lakes Nam Co and Selin Co from ICESat altimetry data

The Geoscience Laser Altimeter System (GLAS) on the NASA Ice, Cloud, and Land Elevation Satellite (ICESat) provides the Earth surface elevation with unprecedented accuracy. The lake level changes over the Tibetan Plateau are poorly known due to the remoteness, high altitude, thin atmosphere, and harsh weather conditions. The water level changes of two largest lakes (Nam Co and Selin Co) are studied using ICESat data over the 2003-2009 period. Results show that both lakes have a increase trend with 0.25 and 0.70 m per year, respectively. The lake level of Selin Co has a high correlation coefficient of 0.91 with lake area reported. Two satellite-based lake elevation data, ICESat data and Topex/Poseidon (LEGOS/GOHS), for the Selin Co show a similar change pattern. These results indicate that satellite altimetry can serve as a powerful and complementary tool for hydrologic monitoring and study.