GC23L-1248
The state and their implication of Himalayan glacial lake changes from satellite observations
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Yong Nie1,2, Yongwei Sheng3, Qiao Liu1, Linshan Liu4, Shiyin Liu5, Yili Zhang4 and Chunqiao Song3, (1)IMHE Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China, (2)University of California Los Angeles, Department of Geography, Los Angeles, United States, (3)University of California Los Angeles, Los Angeles, CA, United States, (4)IGSNRR Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing, China, (5)CAREERI/CAS Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Cryospheric Sciences, Lanzhou, China
Abstract:
Glacial lake outburst floods （GLOFs）generally result in catastrophic damages and fatalities. The Himalayas, the world’s highest mountains hosting large number of glaciers, have frequently suffered from GLOFs events in the past decades. Climatic warming-induced melting and retreating glaciers make glacial lakes expand obviously and urge the potential risk of GLOFs in Himalayas. However, our knowledge on the state of glacial lakes in the entire Himalayas is still limited. This study conducts a systematically satellite-based inventory to firstly reveal the evolution complex, regional difference and causes of Himalayan glacial lake changes in the whole Himalayas. Hundreds of Landsat images and Google Earth high resolution imagery were employed to extract the extents of glacial lakes at four epochs (circa1990, circa 2000, circa 2005 and circa 2010). Object-oriented mapping method was used to automatically map the lakes. In association with published glacier data (e.g., China Glacier Inventory, Randolph and GLIMS Glacier data), visual inspections and iterative checks for individual lake guarantee the accuracy of our results. This study demonstrates the spatial and topographic distributions, differences, heterogeneity of glacial lake changes and their causes. Our results show that Himalayan glacial lakes present a rapidly expanding state in general. Both disappeared lakes and new-formed lakes were observed, however, pre-existing glacial lakes contributed most to the total areal expansion. Himalayan glacial lakes appeared a clear altitudinal difference between north side and south side of main range. Evolutions of glacial lakes between eastern, western and central Himalaya were different, and the most rapidly expanding areas need to be more concerned. Climatic and geomorphic controls result in the heterogeneity of glacial lake changes. This study will help assess the potential risk of GLOFs and promote the public awareness of glacial disasters in high mountain areas.
