Study On The Change Of Lake Area In Inland Lakes In Typical Grassland Area Of Inner Mongolia

In order to explore the differences in the area change of inland lakes and the main driving factors of lake changes in the typical steppe areas of Inner Mongolia,the selection of the Darinor Lake in Keshiketeng Banner of Chifeng City and the Chagan Lake in Abaga Banner of Xilin Gol League were selected as research objects.Taking the topographic map of Xilin Gol of Inner Mongolia compiled by the Survey and Mapping Bureau of the General Staff of the Chinese People's Liberation Army in 1971 as the reference base map,using Landsat remote sensing image as the data source,using MNDWI to calculate and count the data of the two lake areas from 1988 to 2017,and analyze the changes trend.Using meteorological climate,water supply,vegetation cover,and human activities as the driving factors for exploring lake changes,the meteorological climate data and water supply data near the lake area were counted;the vegetation coverage in the two lakes was calculated using NDVI;and the human production activities in the two lakes were analyzed.Summarize the variation characteristics of four driving factors in the two lakes watershed from 1988 to 2017.Correlation analysis and grey correlation analysis of each of the quantifiable indicators of the driving factors and the lake area of the two lakes,quantitative and qualitative analysis of the driving factors of lake area fluctuations,exploring the response of lake area to driving factors,finding the year range in which the lake fluctuates wildly and analyze the main reasons.The results show that:(1)In 1988~2017,the lake areas of Darinor Lake and Chagan Lake have different degrees of atrophy,and the latter has a more severe atrophy.Darinor Lake has shrunk by about 30.0km2 in 30 years,and 2000~2011 is the fastest-decreasing year range for Darinor Lake.Chagan Lake has shrunk by about 69.2km2 in 30 years.After 1999,it is the year range of the violent fluctuations of Chagan Lake.(2)The Darinor Lake area and the Chagan Lake area belong to the mid-temperate semi-arid continental monsoon climate,and the meteorologicalindicators are close,with the same trend and magnitude.In the more than 10 years from 1999 to 2011,the climate of the two lakes has become warm and dry.Drought and less rain,rising temperatures,increased evaporation,lower relative humidity and higher drying index are the main characteristics of climate change.There is no obvious strong correlation between various meteorological indicators and lake area,and the degree of correlation of change characteristics is not close.(3)The atmospheric precipitation recharge and surface runoff recharge of Darinor Lake and Chagan Lake have all decreased to varying degrees.The main reason is that climate warming and unreasonable development and utilization of water resources in the basin by human production activities.The results of the natural variation of lake water show that the lake water income of Darinor Lake is less than expenditure in recent years,while the lake water income of Chagan Lake is greater than expenditure.The natural variation of lake water in Darinor Lake and the water consumption of human production activities affect the change of lake area;while the natural variation of lake water in Chagan Lake is contrary to the fact that the lake area is drastically reduced,the water consumption of human production activities is too large,causing the lake area to shrink sharply.(4)The vegetation coverage rate in the Darinor Watershed has decreased in recent years,and the water conservation capacity in the watershed has been weakened.However,the vegetation coverage rate in the Chagan Watershed has been relatively stable over the years,and the water conservation capacity in the watershed has not changed much.There is no obvious strong correlation between vegetation coverage and lake area in the two lakes,and the degree of correlation of the changes is not close.(5)There are extensive and active human production activities in the vicinity of Darinor Lake and Chagan Lake and its watershed after 2000.The Darinor Watershed is mainly characterized by the accumulation of animal husbandry in the watershed and the conversion of large-scale natural grassland to feedland;the scale of industrial and mining development is large,the mining water consumption and displacement are large;the tourist attractions in the watershed are scattered,the number is large,the standard is low,and the shortage is low,and the proper infrastructure is lacking;these conditions have improved after 2012.The Chagan Watershed is mainly characterized by the industrial and mining production methods in the watershed are extremely extensive,directly taking surface river water for industrial production,most enterprises only manage development regardless of protection;the construction of dykes,sluice gates,and interception and storage of water are more serious,converting a natural lake into a reservoir,directly cut off the supply river of the Chagan Lake;these conditions still exist today.(6)The fluctuation of lake area in Darinor Lake is the result of the interaction of climate change and human activities.The violent fluctuations in the lake area of Chagan Lake are dominated by human production activities;the interception of water storage and extensive exploitation of water resources are the decisive factors for the drying of the large lakes on the west side.