Remote Sensing Dynamic Monitoring Of Main Lakes' Hydrology In Central Asia

Lakes are sensitive indicators of climate and environmental changes and are important information carriers to uncover global climate change and regional responses.The dynamic change of lakes is the result of the combination of climatic factors such as precipitation,temperature,evaporation,and the social and economic activities in the basin,which can reflect the water balance of a basin.A full understanding of the changing patterns of lakes can better capture the dynamic changes of lakes and their basins.In recent years,with the continuous improvement of remote sensing technology,new technical means have been provided for the monitoring of water level and area of inland lakes,to make up for the lack of observation data remote inland lakes,and to provide effective and continuous observations.Based on the data of Landsat and Topex Poseidon/Jason-1/Jason-2,this paper extracted the main lakes(Ebinur Lake,Balkhash Lake,Sayram Lake,Issyk-Kul Lake,Alakol Lake,SaSykkol Lake and Kapchagay Reservoir)area and water level information and their changes from 1990 to 2015 in Central Asia.This article divides lakes into the following three types:Lakes in the Plains: Including Ebinur Lake and Lake Balkhash,whose area is more volatile;Alpine enclosed lakes: including Sayram Lake,Issyk-Kul Lake,and Alakol Lakes;Through Lake: Includes SaSykkol Lake and Kapchagay Reservoir.The dominant factors in the change of hydrological factors in different lake types are also different.The enclosed lakes in plateau(Salim Lake,Issyk Lake,and Lake Allah),are affected by elevation more abundant than the surrounding plains.In addition,affected by the increase in global temperatures,a large number of high-altitude snow and ice melted directly into the river,and the river runoff increased,and the amount of water entering the lake also increased.In addition,there are fewer human activities in the plateau,no industrial and mining enterprises,and less water consumption.However,for Lakes in the plain area,the increase of temperature increases the evaporation of the lake surface.Although the river runoff replenished by the glaciers increased with the warming of the climate,rivers were intercepted for irrigation,which result in that the climate became warmer and the irrigation water increased.The actual surface runoff into the lake was reduced..Compared with the downward trend in the lake area between the plains and the stable rising trend of the plateau closed lakes,the areas of SaSykkol Lake and Kapchagay Reservoir are complex and changeable and are mainly affected by human activities.