Glacier Change In The Pamir Based On Remote Sensing And GIS Over The Period Of 2000 To 2017

Mountain glaciers are the product of the combined effects of climate and terrain.As a part of climate system,mountain glaciers have an important impact on climate change,water cycle and ecosystem.Pamir is the“water tower”of the Central Asia,the glacial meltwater is extremely important in the context of global change.However,the glacier change of the Pamir triggered widespread controversy.In this study,Landsat TM/ETM+/OLI images were used to extract glacier outlines by manual delineation,SRTM DEM and ASTER-derived DEM were used to examine the glacier surface elevation change in the Pamir.In addition,CRU grid meteorological data were used to analyze the changes in summer temperature?June-August?and annual precipitation in the study area from 1981 to 2018.Here,we evaluated glacier area and mass changes from 2000-2017 derived from remote sensing data.The main conclusions are shown as following:?1?In 2017,there were 11079 glaciers covering an area of 10431.03±409.56 km² in the Pamir.From 2000 to 2017,the glacier area in the Pamir decreased by 89.86±68.48 km²,the area shrinkage rate is 0.42±4.34%or 0.02±0.26%a^-1,which is not significant.The glacier area change of the Pamir shows significant spatial difference.The northwest and east regions with dense glacier changed weakly,and the southwest and south regions with sparse glacier shrank obviously.The existence of a large number of advancing glaciers,surging glaciers and debris covered glaciers enhanced the spatial difference of glacier area change in the study area.Compared with other regions in High Mountain Asia?HMA?,the glacier shrinkage rate of Pamir is close to the West Kunlun and Karakoram mountains,but it is significantly smaller than other regions in HMA.?2?From 2000 to 2017,the glacier surface elevation in the study region decreased at a the average mass budget of the Pamir was nearly balanced after 2000.The mass balance of glaciers in the Pamir also shows obvious spatial difference.The mass loss in the northwest and east of Pamirs is obvious,while that in the South and interior is weak.The mass balance of glaciers in the northwestern Pamir from 2000 to 2017 was-0.06±0.13m w.e.a^-1.Combined with the abnormal pattern of glacier surface elevation change and the existing surging glacier inventory,42 of the surveyed glaciers in northwestern Pamir were active glaciers,but the mass balance of surging glaciers(-0.05±0.14 m w.e.a^-1)and non-surging glaciers(-0.08±0.13 m w.e.a^-1)is close.Compared to other regions of HMA,the glacier mass loss in the Pamir is weak.?3?There is a good consistency between the spatial difference of glacier mass balance and the spatial difference of temperature change in summer in Pamir,which shows that the change of glacier mass is mainly affected by the temperature change.But at the same time,the glacier scale,orientation,elevation and glacier debris et.al have greatly enhanced the spatial difference of glacier change,especially the area change in Pamir.