Analysis Of Lake Water Quantity And Its Temporal And Spatial Variation On The Tibetan Plateau Based On Remote Sensing Geology

Under the global warming,the climate of Tibetan Plateau,which is know as "water tower of Asia",shows the tendency of warming and humidification.Lakes on the Tibetan Plateau are scarely influenced by human activities,thus their changes can truly reflect the climate change of the Plateau and even the world.Therefore,the study of lakes on the Tibetan Plateau is important to understand the climate of the "third pole" region and even the world.Based on DEM data,combined with geological structure data,this paper analyzes the internal relationship between lakes and geological processes on the Tibetan Plateau,and build the relationship between lake elevation and area from remote sensing data.Using GEE platform to process the JRC aquatic product data to obtain the area of lakes.Meanwhile,the water level were integrated from altimeter satellite such as Envisat /RA-2,Cryosat-2/ Sral and Jason-2.After removing the outliers in lake water level and area by Cook distance,the relationship model of lake water level and area based on remote sensing was established.After that,based on ASTER GDEM V3 data,the relationship between water level and area based on DEM was constructed and compared with the relationship model from remote sensing.Then,the water volume of lakes on the Tibetan Plateau was estimated based on the relationship between water level and lake area.Finally,the temporal and spatial variation of the water storage of lakes on the Tibetan Plateau were analyzed.The main results and conclusions of this paper are as follows:1)Geological structures shape the form of basin and determines the shape of lake.The morphology,size and spatial distribution of lakes are affected by geological structures.In the horizontal plane,the lake shape is mostly elliptical under the influence of geological structure,while in the vertical section,the lake basin topographic fluctuates to different because of the effect of multiple geological structures.2)Theoretically,the relationship model between water level and area are different in different lakes,and even different in the same lake with different development stages.Influenced by the shape of lake basin,the model always shows linear,quadratic and exponential relationship.3)The lake water-area models based on remote sensing and DEM are consistent.Results based on DEM is a efficient method to reduce the its error caused by the uncertainty of satellite data.On the other hand,remote sensing results can fill up the gap of DEM results.Thus,the accuracy of the results improved by compared with the models from two methods.4)Lakes on the Tibetan Plateau showed a trend of overall expansion and partial shrinkage.The increasing trend of water level is higher in the northern part,especially the Salt Lake,Yongbo Co and Bangda Co.The lake area showed a trend of expanding in the northern part and stabilizing in the south,especially lakes Serinco,Ayakkumu and Salt Lake.The pattern of water volume increasing mainly happened in large lakes,such as Selinco,Namco and Qinghai Lake.