科研之友
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摘要
Debris-covered glaciers are widely distributed in western China. Supraglacial debris lying at the atmosphere-glacier interface plays an important role in the air-ice energy flux and thus influences the underneath ice melt rate. Varying glacier debris thickness will have influence on the mass balance gradient of the debris-covered glacier, the development of ice cliff, ponds and drainage systems, as well as on the downstream runoff process. Using Landsat TM/TIRS images between 1990 and 2019, this study extracted the debris coverage and estimated the thickness changes of the debris-covered glaciers in the Mount Gongga by using a physically-based thermal conductivity method. We found that: (1) The debris coverage of glaciers in the study area totally expanded by 43.824 km2, among which the Hailuogou Glacier expanded 2.606 km2, Mozigou Glacier 1.959 km2, Yanzigou Glacier 1.243 km2, Dagongba Glacier 0.896 km2, Xiaogongba Glacier 0.509 km2 and Nanmenguangou Glacier 2.264 km2. Annual expansion rates of their debris covered area are 3.2%, 11.1%, 1.5%, 0.9%, 1.0% and 6.5%, respectively. (2) In addition to debris cover area expansion, we found thickening debris layers, with glacier wide average debris thickness increasing by 5.2 cm, 3.1 cm, 3.7 cm, 6.8 cm, 7.3 cm and 13.1 cm for the above six mentioned glaciers, respectively. (3) Compared with glaciers on the east slope, debris-covered glaciers on the west slope of the Mount Gongga generally have higher debris cover rate but experienced lower debris cover expansion and lower terminal retreat rate during the past decades.
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单位中国科学院; 中国科学院大学
