Analysis of the Lake Spatio-Temporal Change in Naqu of Tibet during Last Thirty Years

Nowadays, global change has drawn world attention of scientists and governments. As the unique region unit, The Qinghai-Tibetan Plateau has become the essential area and the hot spot of studying climate change because of its unique nature in the global environmental variation. Glaciers and lakes on the Qinghai-Tibetan Plateau are very sensitive to the climate change as one of the important components in environment. In the last thirty years, climate change over the Qinghai-Tibetan Plateau is obvious. More and more scientists pay attention to its modern climate change and its impact. Taking the topographic map (1:50000) in 1980 as the common base, the series of Landsat MSS, TM/ETM+ images that we used in the research are reprojected to the same coordinate system. Then all data sets are orthorectified based on the DEM data and are accurately co-registered to the topographic map with an accuracy of 1 pixel. All data sets are resampled to 28.5 meters in GRID format. Lakes in Naqu of Tibet are compiled by supervised classifications and on-screen digitizing by manual delineation from the digital images and the topographic map. In ArcGIS, the spatio-temporal integrated data of lake is generated. In this paper, the spatio-temporal variation of lakes in Naqu of Tibet during last thirty years by spatial and temporal integration using Remote Sensing and GIS technologies has been studied. The area of lakes and the quantity of lakes of every county in Naqu of Tibet have been calculated.