2000-2020年中亚大型湖泊湖冰物候时空变化OA北大核心CSTPCD

The phenology of lake ice is a sensitive indicator of regional climate change.Through comprehensive analysis of long-term surface reflectance data,meteorological data,and lake information for seven large lakes(Karakul Lake,Balkhash Lake,Aral Sea,Alakol Lake,Zaysan Lake,Chatir Kol Lake,and Markakol Lake)with an area greater than 100 km2 in Central Asia from 2000 to 2020,GIS-related technologies were used to explore the characteristics of lake ice phenology and its influencing factors.The results are as follows:(1)Lakes in Cen-tral Asia began to freeze from mid-September to early November and completely froze from late November to late December,with an average freezing time of 35 days;lake ice began to melt from late March to mid-May and would completely melt from early April to early June,with an average melting time of 18 days.(2)From 2000 to 2020,the start dates of ice formation in five of the seven lakes in Central Asia exhibited a delayed trend,with an average delay rate of 4.86 days per decade,whereas the start date of Balkhash Lake exhibited an advancing trend,with an advancing rate of 1.44 days per decade.The analysis suggests that this may be due to a decrease in the an-nual average temperature in the winter half of the year.The complete melting dates showed an advancing trend,with an average advancement rate of 2.90 days per decade.The average ice-covered period for the seven lakes was 171 days,with four of the lakes exhibiting a trend of shortening of the ice-covered period.The complete freezing period shows an overall trend of shortening,with Balkhash Lake exhibiting the most significant reduc-tion,with a rate of 9.02 days per decade.(3)The spatial pattern of the formation and melting of lake ice in the seven lakes in Central Asia can be mainly divided into two categories:the lake water gradually freezes from both sides to the center and melts from the lake shore to the opposite side,or the lake water freezes from the shore to the opposite side and the earlier freezing,lake area melts the sooner.(4)The lake ice phenology changes in Cen-tral Asia are influenced by multiple factors such as lake characteristics(altitude and area)and climate(tempera-ture and precipitation).Temperature is the key factor affecting lake ice phenology,and the higher the temperature,the shorter the ice-covered period.The area primarily affects the freezing date of the lake,and the larger the area,the shorter the ice-covered period.As the altitude increases,the ice-covered period of the lake extends.