Using RS And GIS Research Of Comparison Between The Ancient Lake Level And The Lake Level Nowadays On Qinghai-tibetan Plateau

This paper use the remote sensing technology and GIS to discuss the high lakes onQinghai-Tibet Plateau, rebuild the area and the altitude, verify the results of previous studies,introduce questions produced in personal studies. And hope to provide some help for thefuture research. In this paper, a total of201lakes on Qinghai-Tibet Plateau are discussed,188of them are above30km2. However, lakes less than30km2all have clear ancient shoreline andhave the research value.This paper record the following data in recovering high lake levels: center of lakes inlongitude and latitude, height of high lakes, height of lakes nowadays, area of high lakes, areaof lakes nowadays, length-width ratio, etc. Statistics and analysis the records of the results,then create the corresponding table and the tendency chart.Researches show that the smallest lake on Qinghai-Tibet Plateau is Duomacuo lake, while the largest is Qinghai lake. Qinghai lake is the largest saltwater lake on the plateau, also it isthe largest lake on Qinghai-Tibet Plateau, Ayakekumu lake is the largest saltwater lake on Qinghai-Tibet Plateau, and Taruocuo lake is the largest freshwater lake there. Lakes on the plateau are mainly saltwater lake. Under normal circumstances, freshwater lakes are less than saltwater lakes in area, except Qinghai Lake, Selincuo lake, Zarinanmucuo lake, Zhaling lake and some other large lakes, meanwhile single salt lakes are relatively large in area. On Qinghai-Tibet Plateau, in addition to a small part of lakes. the vast majority of lakes are between4000m to6000m in altitude,4616.51m in average. Among them, Senlicuo lake,5393m in altitude, isthe highest elevation lake on the plateau, while Gahai lake,2682m in altitude, is the lowestelevation lake on the plateau. Number of lakes is not proportional to the area.After the recovery of high lakes, distribution of lakes changed from scattered into banded, while distribution of lake surface nowadays and high lake surface is different in different area. Number of lakeshore in most lakes are concentrated in5~15. So it can be proved that highland lakes retreat with a certain regularity and uniformity. During the high lake time, the altitude on the plateau is contrary to now along the latitude. During the last interglacial period, about30kaBP, the Great Lakes period on Qinghai-Tibet Plateau is indeedly existed. Since the climate dries, lakes narrowed, During the past40years, plateau lakes rose dued to climate warming, but this is just a small fluctuations of climate linear drying, in the time period, the major trend of lakes are still drying and salinization.