Spatial And Temporal Variation Characteristics Of The Typical Lake And Lake Group In The Tibetan Plateau Under Climate Change

As an important part of the terrestrial hydrosphere,lakes are important information carriers to uncover global climate change and regional responses.There are the plateau inland lake region in the Qinghai-Tibet Plateau,which are the highest elevation largest number and area on the earth.Since most of the lakes in Qinghai-Tibet Plateau are less affected by human activities,their changes can better reflect the transformation in the natural environment.In this paper,Firstly,we chose Qinghai Lake and Lake group in BeiLu River Basin are typical research objects,since Qinghai Lake is the largest lake in Qinghai-Tibet Plateau and the Lake group in BeiLu River Basin is the most dense lake area.Then,we use remote sensing image data to automatically extract water bodies,including 110 remote sensing images from the landsat satellite which can cover Qinghai Lake and two remote sensing images in BeiLu river basion from SPOT-5 and GF-1 satellites.Next,we use weather data from the China Meteorological Network to analyze the climate change in the two research areas from1987-2016.Finally,analyzing the relationship between changes in typical lakes and the climate.The main conclusions are as follows:(1)The water boundary of Qinghai Lake extracted by the new method,which is IDLWI+Canny proposed in this paper,has good effect on continuity and location accuracy,especially in riverbanks and wetlands;In addition,we combine the MNBWI and new spectral correlation method with Canny operator to extract lake group in BeiLu River by the high-resolution remote sensing images from SPOT-5 and GF-1,and the new method greatly improves the processing speed and accuracy.(2)Over the past 26 years(1987-2013),the precipitation changes from the dry season to the wet period and the temperature changes from cold to warm in the Qinghai Lake basin and Beilu River basin.Therefore,the climate in the typical lake research area of the Tibetan Plateau is changed from the 'cold and dry' to ' warm and wet'.Affected by this,the area of Qinghai Lake has changed from decreasing to rising from 1987 to 2016,while the area and number of lakes in the Beilu River Basin haveincreased significantly from 2003-2015.(3)Spatially,the shoreline of the eastern and western shores of the Qinghai Lake has changed significantly compared with the south and north shores.Through analysis,it is found that the change in Qinghai Lake is closely related to precipitation,but not to the temperature.Meanwhile,the number and area of the lake group nearby Beilu River and Xiushui River as well as their intersections with the Qinghai-Tibet Railway are experiencing the consistent increase.we inferred that there are great eco-environment changes,and considering the changes of lake group,the eco-environment in the study area is becoming deteriorated,which may be caused by the river heat conduction,surface run off,and human activities such as the Qinghai-Tibet railway engineering made to the thermokarst lakes nearby.