关键词: 阿尔金山, 冰川变化, 遥感监测, 气候变化

Abstract: This paper extracted glacier borders of Altun Mountains,southeast Xinjiang,China in 1973,1999, 2010,and 2015 based on Landsat images of MSS,TM,ETM⁺,and OLI,respectively,to analyze glacier changes. As ice showing strong reflection in the red band,and absorbing strongly in the SWIR band,adopting a ratio between the red and the SWIR bands could extract glacier data faster,most importantly,the band ratio methodology for extracting glacier showed a high precision and reliability. In addition,we applied ArcGIS 10.2 for connecting a visual interpretation and geographic information technology to modify glacier borders. Therefore,this paper focused on the discussion and analysis of the relationship between glacier retreat and climate changes based on the meteorological stations obtained around the study area. We selected four meteorological stations nearest to the study sites to simulate the climate changes based on annual average temperature;annual precipitation and summer mean temperature. Generally,the summer mean temperature and annual precipitation play a decisive role for glacier melting. Because the study area adjoined to arid regions,the research on glacier changes has important effects on the water cycling system in arid regions. The results showed as follows:(1)The total glacier area decreased from 351.11 km² to 292.33 km²,with an overall loss of 58.78 km²,and the annual rate of retreat was 0.40%·a^-1,while the retreat rate was larger in the eastern glaciers than that of the central and the western glaciers, and the slowest retreat rate observed in the central glaciers. It is obvious that different area presented various glacier retreat rate. In addition,the glacier retreat rate of the study area became larger in the former period and then it became smaller in the latter during the past 42 years.(2)All the glacial areas decreased in various aspects,and generally,the glacier area decreased more in the southern-facing slopes than that in the northern-facing slopes because the southern-facing slopes receive more solar radiation than the northern-facing slopes.(3)The smaller glaciers appeared to shrink faster than the larger glaciers have and showed a non-linear relationship between glacier retreat rate and glacier scale grades. Based on some related research,we may acknowledge that the smaller glacier expresses more dynamic than that of the larger,in addition,the volatility of smaller glacier is more violent than that of larger glacier and the smaller glacier stability index is low. Therefore,the smaller glacier melted faster than the larger glacier.(4)The glaciers show a normal distribution with the increasing of elevation,and the retreat rate of the glacier was larger at a lower elevation than that at the higher. In addition,the glacier retreat curve became gentle as the elevation increases. The temperature at lower elevation area is greater than that at higher elevation area,moreover,the terrain becomes steeper as the elevation increases,thus,the steep terrain is might be the disadvantage for glacier accumulating. A normal distribution of glacier existed because of these two factors. It is acknowledged that the global warming trend is obvious,while precipitation increased slightly. The linear fitting of climate data of the study area revealed that the temperature continued to raise over the past 42 years,however, precipitation changed slightly. Therefore,climate warming is the main cause for glacier area decreasing during the last 42 years;in addition,terrain and glacier scale also influence glacier changes.

Key words: Altun Mountains, glacier changes, remote sensing detection, climate changes