2000—2020年新疆冰湖分布时空特征分析及影响因素分析

Spatio-Temporal Characteristics and Influencing Factors of Glacial Lake Distribution in Xinjiang from 2000 to 2020

冰湖是干旱区水资源系统的重要组成部分,探究新疆冰湖变化监测可以为内陆干旱区气候自然变化过程及冰湖溃决等灾害风险评估提供参考。使用Google Earth Engine(GEE)进行基于随机森林法的监督分类,分析新疆2000—2020年冰湖变化情况,并进行影响因素分析。结果表明:(1)过去20年新疆冰湖数量和面积均呈增长趋势,截止到2020年新疆冰湖数量4 027个,面积208.76 km^(2),其中昆仑山冰湖数量占比22%,天山占比50%,阿尔泰山占比28%。(2)新疆面积小于0.1 km^(2)的冰湖数量最多,平均占冰湖总量的54.71%,面积大于0.2 km^(2)的冰湖面积占比最大,占总面积的54.07%,新疆冰湖数量分布峰值位于海拔3 400~3 600 m,面积分布峰值3 600~3 800 m。(3)研究区冰湖数量和面积与温度和降水均呈不显著相关,与冰川面积呈显著负相关,冰川面积变化是影响冰湖变化的主要因素。

Glacial lakes are an important part of the water resources system in arid areas.Exploring the monitoring of glacial lake changes in Xinjiang can provide references for the natural climate change process and disaster risk assessment such as gla-cial lake outburst in arid areas.This study uses Google Earth Engine(GEE)to conduct supervised classification based on random forest method,and analyzes the changes of glacial lakes in Xinjiang from 2000 to 2020,and analyzes the influencing factors.The results show that:(1)the number and area of glacial lakes in Xinjiang have shown an increasing trend in the past 20 years.By 2020,there are 4,027 glacial lakes in Xinjiang with an area of 208.76 km^(2),among which the number of glacial lakes in Kunlun Mountain accounts for 22%,Tianshan Mountain 50%and Altai Mountain 28%.(2)In Xinjiang,the number of glacial lakes with the area smaller than 0.1km^(2) is the largest,accounting for 54.71%of the total glacial lakes on average,while those with the area larger than 0.2 km^(2) account for the largest proportion,accounting for 54.07%of the total area.The peak of the number of glacial lakes in Xinjiang is located at an altitude of 3,400 m to 3,600 m,and the peak of the area distribution is 3,600-3,800 m.(3)The number and area of glacial lakes in the study area are not significantly correlated with temperature and precipitation,but are signifi-cantly negatively correlated with glacier area,and the change of glacier area is the main factor affecting the change of glacial lake.