University of Cambridge > > Scott Polar Research Institute - Polar Physical Sciences Seminar > Characteristics and changes of glaciers, rock glaciers and glacial lakes in High Mountain Asia since the 1960s

Characteristics and changes of glaciers, rock glaciers and glacial lakes in High Mountain Asia since the 1960s

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High Mountain Asia (HMA) contains large glaciated areas and has great climatic diversity. Large parts are moreover influenced by permafrost and numerous rock glaciers also exist. While previous studies have showed that the glaciers in HMA have lost a significant amount of mass overall, the mass balance is variable and some glaciers have gained mass. While the general mass balance trends are well known, several important factors and processes in the evolution of debris-covered glaciers and rock glaciers are less well understood. One reason is the lack of long-term observations. To overcome these obstacles we use declassified high-resolution stereo Corona data from the 1960s and stereo Hexagon data from the 1970s in conjunction with more recent high-resolution stereo satellite data. Results show that many large rock glaciers evolved from moraines and debris-covered glaciers under permafrost conditions. Rock glaciers in the Tien Shan and Himalaya showed on average no significant surface elevation changes but typically surface lowering in the upper reaches and elevation gain at the front, indicating ice transported by downslope creep. Preliminary results of glacier mass balances revealed increasing mass loss on average, with the highest mass loss occurring in northern Tien Shan and Nyainqentanglha and with balanced mass budgets in eastern Pamir since the 1960s. The debris-covered glaciers at Mt. Everest showed significant surface lowering of partly more than 100 m. The highest lowering occurred at Imja glacier where the proglacial Imja lake expanded rapidly since the 1960s. The increased mass loss of glaciers with pro-glacial lakes could be confirmed for the whole Himalaya, but no substantial difference in the mass loss of debris-covered and clean-ice glaciers since the 1970s could found. Glacial lakes do not only influence glacier mass loss but prose also a serious threat to the society. Analysis of the lakes in Tibet showed partly rapid lake growth, with 16% of all glacial lakes threatening human settlements. These results are important for stakeholders either directly for planning hazard mitigation measures or indirectly as they provide important baseline data to improve glacio-hydrological models.

This talk is part of the Scott Polar Research Institute - Polar Physical Sciences Seminar series.

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