Remotely Sensed Inundation Of Lakes Across Tibetan Plateau And Its Responses To Climate Variation

The Qinghai Tibet Plateau is the birthplace of the Yellow River,the Yangtze River,the Mekong River,In recent years,under the background of global warming,the glacial melt water in the Qinghai Tibet Plateau has increased,and most of the lake area is expanding.The inundation frequency and inundation range in the inundated area have increased,threatening the roads and grasslands around the lake area.This paper uses Google Earth engine platform,based on JRC Monthly Water History(v1.1)data set and China Meteorological Forcing Dataset provided by the national Qinghai Tibet Plateau scientific data center as the main data source,supplemented by basic information such as watershed boundary,analyzed the inundation area,Inundation frequency and its changing trend of 76 Lake inundation areas in the Qinghai Tibet Plateau,and discussed the inundation characteristics of inundation areas Response to climate change.The main results and conclusions are as follows:(1)Based on the JRC Monthly Water History(v1.1)data set,the monthly water boundary data of 76 lakes in the study area from 1986 to 2018 are obtained;on this basis,the inundation characteristic indexes of the inundation area are extracted,Including the annual average inundation area,annual maximum inundation area,total inundation area,inundation frequency,change rate of inundation area and proportion of change rate of inundation area.(2)Based on the method of time series analysis,the dynamic trend of inundation characteristics is revealed.The results show that the average annual inundated area of the Qinghai Tibet Plateau increases at the rate of 207.42km~2/a(R~2=0.906)in the whole research period,and the change of inundated area can be divided into three stages:1986-1992 is a period of fluctuating growth,1992-1997 is a period of shrinking,1997-2018 is a period of rapid growth.From the perspective of spatial differentiation,the frequency of inundation in the northern part of the Qinghai Tibet Plateau changes greatly,especially in the central and northern part of the Qinghai Tibet Plateau.(3)The relationship between inundation characteristics and climatic factors in the inundated area of the Qinghai Tibet Plateau is studied by using statistical method.The results show that the increase of annual inundation area in most of the lake areas of the Qinghai Tibet Plateau is mainly affected by the increase of precipitation and temperature.the correlation between the annual inundation area and the maximum temperature is the best.Among the rainfall indexes,the minimum cumulative rainfall in the basin has the best correlation with the annual inundation area and the annual maximum inundation area.From the perspective of spatial distribution,the change of inundation characteristics in the Northwest Lake area has a strong correlation with rainfall,while that in the South Lake area has a strong correlation with temperature.