Dynamic changes of lakes and the geo-mechanism in Tibet based on RS and GIS technology

Abstract

Using the topographic data at the scale of 1:100000 in 1960's, and Landsat MSS in 1970's, Landsat TM in 1990's, Landsat ETM+ in 2000's, we carried out the survey of the lake distribution and its dynamic changes on Tibetan Plateau. The result indicates that there are 3 lakes within the area more than 1000km2, 74 lakes within area more than 100km2, 382 lakes within the area more than 10km2, 1260 lakes with the area more than 1km2, 6882 lakes within the area more than 0.1km2, and the total area of lakes is about 43186.4km2 on Tibetan Plateau. The area of lakes has taken place significantly changes during the past 30 years. The total area of lakes has increased 1610.01km2. The area of increased lakes are 157 lakes within area more than 1km2, 5411 lakes within area more than 0.1km2 and small lakes increased in hundreds and thousands. The area and amount of lakes increase most obviously in Qiangtang Plateau and Kunlun Mountains, and decrease most obviously in Qaidam basin, Hexi Corridor, Yellow River Basin, Yarlung Zangbo River Basin. The expanded and newborn lakes are distributed in the inner Plateau and disappeared and decreased lakes in the surrounding area of the Plateau. The increase and decrease of lake area has some related with climate changes, but mainly related to the local topography controlled by neo-tectonic.