Area Change And The Evaporation Estimation Of Dabson Lake In Qinghai Province

Lake resources account for 95%of the world's total liquid fresh water resources,and the dynamic change of lake area is affected by the dynamic change of water balance in its basin.At present,lake shrinkage is one of the major environmental problems facing mankind.The formation and disappearance,expansion and shrinkage of lakes,to some extent,it will reflect and affect the local and even global climate,ecological environment,geological structure and other aspects.Therefore,study on the dynamic change of lake area,can understand the regional water balance in time,and further reveal the impact of natural factors and human activities and other external factors on the change of lake area,which is of great significance to the sustainable development,scientific utilization and protection of lake resources.In this paper,Landsat5,7 and 8 satellite data with a spatial resolution of 30 m are obtained by remote sensing technology.The modified normalized difference water index(MNDWI)and the adapted Surface Energy Balance System(SEBS)model are used to calculate,extract and reverse the lake area and lake surface evaporation capacity of Dabson Lake.At the same time,the correlation between the lake area and various influencing factors is explored in combination with factors such as air temperature,evaporation,sunshine hours and salt lake exploitation.The grey-Markov model is used to predict the lake area in 2030.This is of great significance to the ecological environment protection and the sustainable exploitation of brine in Dabson Lake,and provides theoretical basis for the evaluation of water resources and the regional ecological protection in the region.The results show that:(1)The annual areas of Lake Dabson increased firstly,decreased later and increased finally during the study period.In winter,the lake evaporation is very small and the lake area is the largest,whereas in summer,the lake evaporation is relatively large,and the lake area is the smallest;(2)The change of lake area in the year has a high correlation with temperature and relative humidity.On the contrary,evaporation,sunshine hours and monthly precipitation have no obvious influence on the change of lake area.(3)From 1987 to 2017,the area of Lake Dabson showed a decreasing trend.(4)The interannual change of lake area has a moderate positive correlation with evaporation and wind speed.(5)From 2010 to 2017,the yield of potash fertilizer is highly correlated with the lake area,and R~2 is 0.840.As the exploitation of Dabson Lake increases year by year,human factors gradually become the main impact factor for the decrease of the lake area.(6)The lake evaporation calculated by SEBS model and the meteorological station evaporation are significantly correlated at?=0.01,R~2=0.974.Therefore,it is reasonable to use SEBS model and Golmud weather station data to calculate the lake evaporation of Dabson lake when the measured meteorological data on the lake surface can not be obtained.(7)Air temperature and sunshine hours have strong correlation with lake evaporation calculated by SEBS model,weak correlation with wind speed and extremely weak correlation with humidity.(8)A grey-Markov model is established,it is predicted that the lake area will be reduced to 106.5 km~2 in 2030,meeting the government planning requirement of not less than 100 km~2 in 2030.