Spatial Distribution,Evolution And Influence Of Supraglacial Debris On Glacier Of The China-Pakistan Economic Corridor And Surroundings

The China-Pakistan Economic Corridor and surrounding glacier areas are widely distributed with debris-covered glaciers,and their typical feature is that the glacier ablation area is covered with a layer of moraine of varying thickness.Compared with bare ice or snow,the debris cover layer has a unique thermal process due to the difference in its physical properties,which has a significant impact on the melting process of the underlying glacier.This paper mainly analyzes the spatial distribution and evolution trend of the debris based on the thermal attribute parameters of the debris retrieved from ASTER remote sensing data,and combines the energy-mass balance model to comprehensively evaluate the influence of the debris distribution on glacier melting.The research results show that:(1)The thermal resistance of the debris in the study area decreases with the increase in altitude,and the thermal resistance of the surface debris on the same elevation zone has significant differences,with an average of 3.6×10^-2 m~2 K W^-1;debris-covered glaciers account for 57.3%of the glaciers and 14.1%of the regional glaciers.Among them,the Himalayas have the largest number of debris-covered glaciers,followed by the Pamirs and Karakoram Mountains.The Hindu Kush Mountain has the least number of debris-covered glaciers and the smallest area.The area covered by the debris is mainly between 3300 m and5800 m above sea level,accounting for 95.8%of the total area covered by the debris.In areas below 3300 m altitudes,most of the ablation area is covered by debris,with a coverage ratio of62%;the average debris thickness of the Hindu Kush Mountains is the largest,while the average debris thickness of the eastern Himalayas is the smallest.(2)The maximum ablation rate of the China-Pakistan Economic Corridor and surrounding glacier areas is mostly in the middle reaches of the glacier ablation area,and the thermal resistance coefficient of the debris corresponding to this value is lower than the average value of each region;except for the Karakoram Mountains and the western Himalayas in the study area.The debris coverage promotes glacier melting,the debris in other regions are mainly to inhibit glacier melting,and the inhibition effect of the debris in the region is more significant than the promotion effect.Among them,the debris suppression effect in the middle section of the Himalayas is the most significant,followed by the Hindu Kush Mountains and the eastern section of the Himalayas.The debris cover has a more significant impact on the glacier melting at each altitude zone,and overall it has the effect of inhibiting the ablation.(3)The evolution state of the surface debris cover with an area of more than 50 km~2 in the China-Pakistan Economic Corridor and surrounding glacier areas is in the stage of transforming from discrete moraine on the surface of the glacier to continuous surface cover.The future expansion potential and moraine abundance of this type of glaciers converge to 0.2 and 1,respectively.