Water Balance Estimates Of Typical Lakes In Arid Region Of Central Asia Using ICESat And Landsat Data

Since 1950,the global average temperature has gradually increased.Meteorological data have been recorded,and the average temperature in the past 30 years is higher than any time period,especially in 2000-2010,which is the highest average temperature recorded since the record;Compared with temperature,the global precipitation on the land surface is not large,and the increase in precipitation is more obvious in the area of 30°~60°N.The arid area of Central Asia is the most important distribution area of inland lakes.Inland lakes are in a relatively independent inland water circulation system,which is affected by climate fluctuations and human activities.In this paper,the lake in Central Arid Zone for the study,based on remote sensing data,satellite altimetry data,MODIS land cover data,meteorological reanalysis data and some site meteorological data,the integrated use of RS and GIS technology,we extracted lakes area information in Central Asia,the water level information and estimated the amount of water changes.Exploring the spatial and temporal variations major lakes in arid areas of Central Asia to study the variation of the response to climate change.Through the study of this article,the main conclusions are as follows:(1)From 2003 to 2009,the lake area in the arid region of Central Asia as a whole showed a process of "continuous shrinkage".Among them,except for the significant increase in the area of the lakes in the Aral Sea(north lake),the seven lakes remained relatively stable,and the other nine lakes were greatly reduced.The area of different types of lakes varies from place to place.Changes in the area of closed lakes in high mountains mainly show a slight shrinking trend.The area of lakes fluctuates over many years,and the change is relatively stable.Spatially,the closed lakes in high mountains vary in all directions.At the same time,there is an increase,stability,and decrease in the area of the plain lake.Although the area of the outflow lakes and lakes is smaller than that of the lakes of the plains,closed lakes in high mountains are larger,but the area of the lakes generally shows a negative growth trend.For the plain lake and the outflow lake,the water inlets and outlets are distributed in the direction of the lake area changes.(2)In the 17 selected lakes in the arid region of Central Asia,the changes in the water level of lakes in different regions and different types of lakes during October 2003 to October 2009 were found to be varied by comparing the changes in the water levels of closed lakes,outflow lakes,and plain lakes.In the model,compared to the plain lake and outflow lake,the water level change is relatively stable.However,there are also differences in water level changes in different regions.The water level of mountain closed lakes in the Pamirs Plateau rises significantly and is relatively stable in the central Tianshan Mountains.The water level rises,stabilizes,and drops at the same time in the Plain Lake.The water level in the Aral Sea(North Lake)rises significantly,while the water level in the Aral Sea(South Lake)drops sharply.Although the water level of outflowing lakes is generally in decline,it is also divided into two situations.The level of the lake where the dam is built is significantly reduced,and the lake level in the natural state remains relatively stable.(3)Using the lake water balance formula,the water volume of 17 lakes in the arid region of Central Asia was generally reduced during 2003-2009.There is a high positive correlation between changes in lake water volume and changes in water levels.Therefore,the change in water quantity of different types of lakes is consistent with the change in water level.The closed lake is basically in a state of balanced water balance,while the plain lake and the outflow lake are in a state of negative balance.(4)Meteorological factors are still the main factors affecting lake changes.The changes of lakes,especially the change of water level and water volume,are positively correlated with the precipitation in the basin,and negatively correlated with the temperature.However,for the closed lakes,there are lakes with glaciers,and the temperature has a positive effect on lake changes.It can be seen that the glaciers have a greater impact on the closed lakes in the high mountains,and these lakes are also more sensitive to changes in climate.As an important factor influencing lake changes,human activities have become increasingly prominent in the arid regions of Central Asia..At the same time,in recent years,the accelerating process of urbanization in central Asia,the increase in population,and the increase in the use of water for industry and living have increased the uneven distribution of water resources in Central Asia,causing huge changes in river runoff and lake water intake,to some extent,it reflects the impact of human activities on lake changes.