1987—2021年羊卓雍错西岸冰川变化及其对气候变化的响应

Glacier Changes at West Bank of the YangzhuoYongcuo From Year 1987 to 2021 and Their Response to Climate Change

冰川是全球气候变化背景下最脆弱最敏感的生态系统之一,冰川变化研究不仅揭示着气候变化规律,亦对水资源的统筹管理和合理开发提供重要参考依据。文章利用高分辨率多源卫星数据结合气象数据对西藏羊卓雍错西岸冰川进行动态监测。结果表明:(1)1987—2021年该区域冰川面积呈显著萎缩趋势,共减少了(20.12±4.51)km~2,占冰川总面积的18.57%±4.1%,年均缩小率为0.54%±0.12%,1987—2006年冰川面积相对稳定,2009年之后冰川面积大幅减少,处于负距平状态;(2)从冰川空间变化看,宁金岗桑峰SW方位的冰川面积最大,占冰川总面积的18.2%±2.4%,萎缩率仅占6.7%±1.2%,其NE方位最小,萎缩率为41%±5.2%;卡鲁雄峰W方位的冰川面积最大,占冰川总面积的30.1%±1.1%,萎缩率最小,其N和NE方位最小,仅占冰川总面积的1.27%±0.18%和0.09%±0.03%,NE方位的冰川分布面积小,萎缩率最大,为97%,主要表现为零碎冰川退缩;(3)2000—2015年表面高程平均减薄5.33 m·a^(-1),年平均物质平衡亏损0.058 m w.e·a^(-1),累计亏损物质平衡为0.93 m w.e,42条冰川呈负平衡状态,63条冰川接近于平衡状态或处于正平衡状态;(4)从冰川区域气象站气候特征发现,冰川面积与年气温呈显著负相关,与年降水呈弱相关,表明冰川变化受温度影响较大,气温升高是冰川退化的主要原因。

Glacier is one of the most vulnerable and sensitive ecosystems in the context of global climate change.Research on the glacier change not only reveals the rule of climate change,but also provides an important reference for the overall management and rational development of water resources.In this paper,the dynamic monitoring of glaciers was conducted at west bank of theYangzhuoYongcuo in Tibet,based on the high-resolution multisource satellite data combining with meteorological data.The results showed that:(1) the area of glaciers in the region has shown a significant shrinking trend in the past 35 years,with a total reduction of(20.12±4.51) km^(2),accounting for 18.57%±4.1 % of the total area of glaciers and an average annual reduction rate of 0.54%±0.12%.The area of glaciers remained relatively stable from year 1987 to 2006,and after 2009,the area of glaciers has been significantly reduced and remained in a negative anomaly state.(2) From the perspective of spatial change of glaciers,the largest area of glaciers is in the SW direction of Ningjin Kangsang Peak,accounting for 18.2%±2.4% of the total area of glaciers with a shrinking rate of 6.7%±1.2%,and the smallest area of glaciers is in the NE direction with a shrinking rate of 41 %±5.2%.The largest glacier area is in W direction of Kaluxiong Peak,accounting for 30.1%±1.1% of the total glacier area with the smallest shrinkage rate,and the smallest glacier area in N and NE directions,accounting for only 1.27%±0.18% and 0.09%±0.03% of the total glacier area.The glacier area is small in NE direction with the largest shrinkage rate of 97%,mainly showing the retreat of fragmented glaciers.(3) From year 2000 to 2015,the average surface elevation of glacier decreased by 5.33 m·a^(-1),the deficit of average annual glacier mass-balance was 0.058 mw·e·a^(-1),and the accumulated deficit of glacier massbalancewas 0.93 mw·e.42 glaciers were kept in negative equilibrium state and 63 glaciers were close to or in positive equilibrium state.(4) According to the climate characteristics of the regional meteorological stations near to the glacier,the change in glacier area is significantly correlated with temperature(P<0.001) negatively,and weakly correlated with precipitation,indicating that change in glacier area is mainly controlled by temperature,and the rising temperature is the main cause of glacier retreat.