1956-2017年河西内流区冰川资源时空变化特征

Spatial-temporal variation of glacier resources in the Hexi interior from 1956 to 2017

基于修订后的河西内流区第一、第二次冰川编目数据及2016-2017年Landsat OLI遥感影像,对河西内流区1956-2017年冰川时空变化特征进行分析。结果表明:(1)河西内流区现有冰川1769条,面积976.59km^2,冰储量约49.82km^3。冰川面积以介于0.1~10km^2的冰川为主,数量以<0.5km^2的冰川为主。祁连山是该区域冰川集中分布区,其冰川数量、面积和冰储量分别占该区域冰川相应总量的98.47%、97.52%和97.53%。(2)疏勒河流域(5Y44)冰川数量、面积及冰储量最多(最大),冰川平均面积为0.81km^2,石羊河流域(5Y41)最少(最小)。从四级流域来看,宁掌等流域(5Y445)冰川最为发育,冰川数量、面积及储量均最大,宰尔莫合流域(5Y446)冰川平均面积最大(1.80km^2),夹道沟-潘家河流域(5Y422)最小,仅有0.05km^2。(3)近60年河西内流区冰川数量减少556条,面积减少417.85km^2,冰储量损失20.16km^3。面积介于0.1~0.5km^2之间的冰川数量与面积减少最多(457条和-117.49km^2),海拔4400~5400m区间是冰川面积集中退缩的区域(98.55%),北朝向冰川面积减少最多(-219.92km^2)且冰川退缩速率最快(-3.61km^2·a^-1)。(4)1956-2017年河西内流区各流域冰川面积均呈退缩态势,区内冰川变化呈自西向东逐渐加快的趋势,但有3条冰川在1986-2017年出现不同程度的前进,气温升高是该区域冰川退缩的主要原因。

Based on the revised First and Second Chinese Glacier Inventories and Landsat OLI imagery in 2016-2017,we analyzed the spatial-temporal variation characteristics of glaciers in the Hexi interior from1956 to2017 and researched the cause and mechanisms of glacier changes using temperature and precipitation data.The results showed that:(1)In total,there were1769 glaciers covering an area of976.59 km^2 and having ice volume of49.82 km^3 in the Hexi interior in2016/2017.The glaciers in0.1~10 km^2 interval contained the largest area and that<0.5 km^2 interval had the maximum number.The glaciers in the study area were mainly distributed in the Qilian Mountains,where the glacier number,area and ice volume accounted for98.47%,97.52%and97.53%,respectively.(2)The Shule River contained the most of the glaciers number,area and ice volume,with average glacier area of0.81 km^2.However,in the Shiyang River it was the minimum.In the fourth class watersheds,the most developmental glacier in the Ningzhang basin included most of the glaciers number,area and ice volume,and the maximum average glacier area was in the Zalmoho basin.To the contrary,JiadaogouPanjia River had the minimum average glacier area(0.05 km^2).(3)In the past60 years,the area,number and volume of glaciers had decreased by417.85 km^2,556 and20.16 km^3,respectively.The majority of glacier area loss in the Hexi interior had been mainly concentrated in between4400~5400 m a.s.l.and the area and number of glaciers in the 0.1~0.5 km^2 interval constituted the main body of the loss(457 glaciers and-117.49 km^2).Within the study region,glaciers with the north orientation suffered the largest area loss,while those with the northwest orientation had the fast change in glacier area.(4)During the period from1956 to2017,the glacier area of different drainage basins had a tendency of retreat in the Hexi interior and the glacier change was gradually accelerated from west to east.However,there were three glaciers had clearly advanced during 1986-2017.The main reason for glacier retreat in this region was temperature rising.