Study On The Changes Of Desert Area,Boundary And Desert Lake In Western Inner Mongolia In Recent 30 Years

The western part of Inner Mongolia is one of the areas where deserts are concentrated and desertification is serious in China.This paper focuses on the five deserts of Badain Jaran,Tengger,Ulanbuh,Yamalek and Bayinwintour,Using Sentinel-2 and Landsat satellites as data sources,using the water body index and human-computer interaction interpretation to obtain dynamic data of desert in 1990,2000,2018 and desert lake in 1990,2000,2010,2018.System analysis the seasonal and annual changes of desert area,boundary,number and area of desert lakes.The effects of seasonal and annual precipitation on desert lakes were discussed.This research has certain theoretical significance and application value for revealing desert changes,desert lake water cycle,desertification control and desert water resources protection.The main results are as follows:1)In 2018,the desert areas of Badain Jaran,Tengger,Ulanbuh,Bayinwintour and Yamalek were 48234.00km~2,40157.7km~2,8539.49km~2,4379.83km~2 and 4362.20km~2,the total area is 105761.7km~2.2)In general,the deserts in western Mongolia have been basically stable in the past 30 years,only expanding by 58 km~2,but the differences in deserts are quite different.The Badain Jaran and Tengger Deserts have remained basically stable,with expansion rates of 0.63%and 0.07%.However,the desert with a smaller area expands faster,and the Bayinwintour Desert expands by 88.48km~2,with a rate of change of2.02%,and the main expansion time is 2000~2018 years;The Amalek Desert has expanded by 107.18km~2 with a rate of change of 2.52%and the main expansion time is 1990-2000.Only Ulanbuh desert area decreased by 471.83km~2,and the rate of change was-5.23%,concentrated in the northeast.3)In 2018,there were 106 existing lakes in the Badain Jaran Desert,including 89perennial water and 17 seasonal lakes;It reaches the maximum in spring,with a total area of 25.35km~2,and the smallest in autumn,with a variation of 5.01km~2 during the year.There are 319 lakes in the Tengger Desert,including 214 perennial water lakes and 105 seasonal lakes;It reaches the maximum in summer,with a total area of416.31km~2 and a variation of 322.78km~2.The correlation between seasonal precipitation and lake area change in Badain Jaran Desert is not significant,and the change of seasonal precipitation in the Tengger Desert during the year is consistent with the change of lake area.4)In the past 30 years,the Badain Jaran Desert Lake has been basically stable.The area of the Tengger Desert Lake has decreased greatly.The area of the Level Period has decreased by 122.54km~2,and the area of the Plentiful Period has decreased by127.74km~2.There are certain fluctuations in the number of lakes during the year,and the number of lakes in Badain Jaran is between 78(2010)and 93(2018);The number of lakes in the Tengger Desert ranged from 199(2000)to 319(2018),with large fluctuations.The Level period decreased significantly between 1990 and 2000,and the Plentiful period continued to decrease after 2000.5)Regardless of the Badain Jaran Desert or the Tengger Desert,the annual cumulative precipitation has not passed the 0.05%significant test for the lake area,indicating that rainfall was not the influencing factor of the interannual variation of the lake.