Research On Characteristics And Influencing Factors Of Qinghai Lake Water Body Variation Based On Remote Sensing Data

As an important hub connecting the atmosphere,hydrosphere,and biosphere,the changes in lakes have a significant impact on the local natural environment and human life.Qinghai Lake is located in the northeastern part of the Qinghai-Tibet Plateau and is the largest inland saltwater lake in my country.Before the 21st century,Qinghai Lake has been in a state of shrinking.Under the influence of global climate change,it has shown a trend of rapid expansion in the past ten years,which has attracted the attention of many scholars.As an"indicator"of local climate change,Qinghai Lake clarifies the factors that affect its changes,which is of guiding significance for maintaining the ecological balance of the region and formulating reasonable protection policies.This paper uses multi-source remote sensing data to monitor the area,water level,and water volume changes of Qinghai Lake from 1956 to 2019.At the same time,Morlet wavelet analysis,sliding T test,cumulative anomaly method,and MK test are used to determine the temperature,precipitation,evaporation,and evaporation of Qinghai Lake.The trend,periodicity and sudden change points of runoff were analyzed;finally,using the principle of water balance and the multiple regression model,the influence of the changes of various factors on Qinghai Lake was discussed,and the conclusions are as follows:(1)From 1956 to 2019,the area,water level and water volume of Qinghai Lake all took 2004 as the turning point,showing a trend of first decreasing and then increasing.In 64 years,the area has decreased by 44.63 km~2 at a rate of 0.69km~2/a,the water level has decreased by 1.05m at a rate of 1.64cm/a,and the amount of water has decreased by 31.38×10~8m~3 at a rate of 0.49×10~8m~3/a.The overall loss is status.(2)From the perspective of changes during the year,from 1961 to 2014,the temperature,precipitation,evaporation,and runoff in the Qinghai Lake Basin showed a trend of first increasing and then decreasing.The increase in precipitation and runoff has led to an increase in lake water volume.Although evaporation is the most important way of water consumption,it cannot play a leading role in lake water changes.From the perspective of inter-annual changes,from 1961 to 2014,all factors showed an increasing trend.(3)Runoff and precipitation are the main replenishment methods of lake water,accounting for 47.5%and 35.1%of the total recharge respectively.The recharge of groundwater to the lake is limited,accounting for only 17.4%.The influencing factors of the lake level change from large to small are:base flow,precipitation,surface runoff,evaporation,the contribution rates are:35%,24%,21%,-20%,precipitation,base flow and surface runoff There is a certain lag in the impact on the water level.