Abstract: In order to analyze the annual,monthly and spatial variations of arid lake extent change under climate change,the Ayakkum Lake in the Alkin Mountains in Xinjiang,China was selected as an example to map the changes of lake area and level based on the time series of Corona and Landsat images in recent 50 years.The results showed that the change of the Ayakkum Lake experienced 3 stages,i.e.the periods of 1964-2004,2005-2010 and 2011-2014,and the annual change rates of their lake area were -0.012 km²·a^-1,-0.256 km²·a^-1 and -4.798 km²·a^-1 respectively.Holistically,the lake area was shrunk gently at first and then significantly,lake water was firstly found to be extinct on September 25th,2014,and its ecological function was weaker and weaker.The seasonal variation of the Chaiwopu Lake extent revealed that the lake water extent reached its peak in spring and was shrunk down to its valley in autumn,the seasonal change became more obvious,and its sharp shrinkage occurred after 2005.Monthly lake area curves showed that the Chaiwopu Lake was lost its water area rapidly year by year.The variation of the Ayakkum Lake was highly similar to that of the Chaiwopu Lake.Before 2005,the change of lake water area and water level was insignificant.After 2005,the lake water area was sharply shrunk.When these lakes was shrunk to their bottoms in 2012,the groundwater level in the study area was highly correlated with the variation of lake water area.In the wet years between 1999 and 2004,the lake shrinking rate was decreased,but a dynamic water balance of the Chaiwopu Lake was kept.Excessive groundwater pump after 1993 was the main reason of lake extinction,which resulted in the ecological disasters in this region.

Key words: lake area, time-series analysis, spatiotemporal change, climate change, response, Ayakkum Lake, Xinjiang