Spatial and temporal changes of glaciers and glacial lakes in the Northern Tianshan Mountains over the past 30 years

近30年来天山北坡冰川冰湖时空变化特征

Glaciers and glacial lakes are very sensitive to climate change,and studying their dynamics is important for revealing changes in global climate.In this study,we extracted the boundaries of glaciers and glacial lakes in the Northern Tianshan Mountains based on Landsat TM/ETM+/OLI and Sentinel 2A/2B MSI remote sensing images and analyzed their dynamics and impacts over the past 30 years.The findings indicate that in 2020,the Northern Tianshan region exhibited a total of 3254 glaciers,with an area of 1670.55 km^(2) and a volume of 95.69 km^(3).The corresponding numbers,areas,and volumes of glacial lakes were 281,13.23 km^(2) and 210.49×10~6 m^(3),respectively.Over the past 30 years,glaciers and glacial lakes have exhibited opposite characteristics.The former decreased by 16,332.64 km^(2)(-0.60%·a^(–1)) and 18.36 km^(3)(-0.58%·a^(–1)),respectively,and the latter increased by 56 and2.48 km^(2)(0.82%·a^(–1)) and 38.88×10~6 m^(3)(0.79%·a^(–1)),respectively.Moreover,different glacier termination types cause differences in the glacier retreat rates.Lake-terminated glaciers retreated faster than land-terminated glaciers,and the type of glacier termination has a greater effect on the retreat rate than the size of the glacial area.