Water-level changes in China's large lakes determined from ICESat/GLAS data

Abstract

Water-level changes from 56 of the 100 largest lakes in China were derived from ICESat/GLAS data during the period of 2003 to 2009. An automated method for determining the trend of water-level change had been proposed in this study. Lake water footprints were first identified from the ICESat/GLAS GLA14 data product. Water level change was then determined from the footprints over lake water in each campaign. Trend of water-level changes was fitted with a line for each lake. Trends of water level changes from ICESat/GLAS matched well with gauge measurements in both Qinghai Lake and Nam Co. Our results showed that the trend of water-level change varied from -0.51. m/a to 0.62. m/a. Eighteen lakes showed a decreasing trend of water-level change and 38 lakes showed an increasing trend. Most lakes in Qinghai-Tibet Plateau showed an increasing trend which was probably caused by snow or glacier melts under climate warming. However, most lakes in the Yarlung Zangbu River basin showed a decreasing trend presumably resulting from intensified evaporation caused by climate warming and intensified western wind in the winter. Desertification and aggravated soil erosion in this region contributed to water level decrease. Lakes in northern Inner-Mongolia and Xinjiang and Northeast Plain of China showed decreasing trends with precipitation reduction and warming as the most probable reasons. Water consumption for agricultural use also contributed to water-level decrease in lakes of those regions. Lakes in East China Plain fluctuated presumably because most lakes were greatly affected by inflows of Yangtze River and human activities. Lakes in Yunnan-Guizhou Plateau also fluctuated. There were no obvious changes in climate warming or precipitation in this region. © 2013.