A Study On The Temporal And Spatial Changes Of The Tianshan Glacier Area In The Past 35 Years

Glaciers are ice bodies with a certain shape and movement that have accumulated over many years in the cold areas of the earth’s surface,and are an important part of the global freshwater resources.Under the background of global warming,the changes of glacier melting in arid regions have a rapid impact on the local ecological environment,and have important indications for global climate change.In this study,Tianshan glaciers were selected as the research object,based on the PIE（Pixel Information Expert,PIE）-Engine cloud computing platform,using the Landsat image data from 1987 to 2021,and using the NDSI method to extract the glacier area.The effects of temperature and precipitation on the change of glacier area were discussed.The results showed that:（1）In the past 35 years,the overall area of Tianshan glaciers has been shrinking,with a shrinking rate of 363.68 km²·a^-1and an average annual shrinkage rate of 1.48%·a^-1.The glacier has retreated most significantly since 2020.Spatially,the glaciers at altitudes greater than 4000 m in the Aksu area of the southern Tianshan Mountains are relatively stable,and the Bayingoleng Mongolian Autonomous Prefecture and the eastern Jingxian area of the Tianshan Mountains are mainly retreated.The changes were relatively drastic,with only a slight accumulation in Wuqia County of Kyzilsu Kirgiz Autonomous Prefecture and Wensu County and Baicheng County of Aksu Prefecture.（2）In the past 35 years,most of the typical glaciers in the Tianshan Mountains have shown a shrinking trend,but the shrinking rate is different in different typical areas.Recession rate of Erbin Mountain5.98%·a^-1>Arshan Mountain 2.19%·a^-1>Qibaerqia Mountain 2.07%·a^-1>Koqikar Peak 2.06%·a^-1>Borg Dafeng 2.05%·a^-1>Hallik Mountain 1.15%·a^-1>Heyuan Peak 0.81%·a^-1.Typical glaciers are in a retreating trend in space,but the retreating speed is different in terrain.The Akso Glacier retreated most significantly on the western slope（-3.58%）,the Kochikar Glacier retreated most significantly on the northern slope（-3.05%）,Alshan Mountain（-4.73%）,Heyuan Peak（-2.72%）The glaciers of Mount Erbin（-5.75%）receded most significantly on the southwest slope,and the glaciers of Mount Haerlik（-0.61%）and Mount Chaibaerqia（-4.79%）receded most significantly on the southern slope,and Bogda Peak glacier area retreated most significantly（-3.28%）on the southeast slope.（3）In the past 40 years,the annual average temperature and annual precipitation in the Tianshan Mountains showed an increasing trend,rising at a rate of 0.332℃·（10a）^-1and 15.274 mm·（10a）^-1,respectively.The area of typical glaciers in the Tianshan Mountains tends to accumulate with the increase of precipitation,while the glaciers tend to melt with the increase of temperature,and the faster the temperature rises,the slower the precipitation rises,and the faster the glaciers retreat.Recession is mainly affected by temperature,and the cumulative effect of increased precipitation is lower than the ablation effect caused by rising temperature.