Dynamic Change Of Lake KHYARGAS And AIRAG,UVS Province,Mongolia

Climate change and increasing human activities have induced lake expansion or shrinkage,posing a serious threat to the ecological security on the Mongolia.However,there are few reports on the patterns of changes in Mongolian lakes and how it deals with climate change and vegetation restoration.This paper takes Khyargas Lake and Airag Lake,typical lakes in arid and semi-arid areas of Mongolia,as the research object.Based on the interpretation of the US Landsat 5TM and Landsat8 OLI remote sensing images from 2008 to 2018,the lake area changes of Khyargas Lake and Airag Lake in 10 years were analyzed and combined with Land Surface Temperature(LST),Normalized Difference Water Index(NDWI),Normalized Difference Moisture Index(NDMI),Evapotranspiration(ET)And the normalized Difference Vegetation Index(NDVI)and other indicators initially explored the driving factors of lake area change.The main results of this paper are as follows:1)The total lake-area in the Khyargas has decreased by 15.0km2 between 2008 to 2018.About Airag lake total surface area changes of the lake between 2008 and 2018 were about 19.51 km2.The results indicate first 5 years an intense decreasing trend in the Airag Lake surface area reduced the most with a rate of-25.87km2 between 2008 and 2013.2)During the period from 2008 to 2018,the temperature in the study area increased by 0.8 °C,and the precipitation decreased.The Land Surface Temperature(LST)was around 30-45 °C,the Normalized Difference Water Index(NDWI)was between-0.5 and-0.8,the Normalized Difference Moisture Index(NDMI)was between-0.2 and-0.7.Evapotranspiration(ET)was between 0-16,while the Normalized Difference Vegetation Index(NDVI)was between-0.5 and-0.2 or less vegetation.3)Changes in the lake area are both the result of natural factors and the result of human activities.The coupling effect greatly accelerates the changes in the local environment.The results of the thesis can provide theoretical basis and data support for lake ecological restoration and integrated river basin management in arid and semi-arid regions of Mongolia.