Glacial lake evolution in the southeastern Tibetan Plateau and the cause of rapid expansion of proglacial lakes linked to glacial-hydrogeomorphic processes

JOURNAL OF HYDROLOGY

卷:540

Article

Song, Chunqiao¹  Sheng, Yongwei¹  Ke, Linghong²  Nie, Yong³  Wang, Jida⁴ 

[1] Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA

[2] Hong Kong Polytech Univ, Dept Land Surveying & Geoinformat, Hong Kong, Hong Kong, Peoples R China

[3] Chinese Acad Sci, Inst Mt Hazards & Environm, Chengdu, Peoples R China

[4] Kansas State Univ, Dept Geog, Manhattan, KS 66506 USA

关键词: Glacial lake;    Tibetan Plateau;    Landsat;    ICESat;    Mountain glacier;    Climate change;   

DOI  :  10.1016/j.jhydrol.2016.06.054

来源: Elsevier

【 摘 要 】

Glacial lakes, as an important component of the cryosphere in the southeastern Tibetan Plateau (SETP) in response to climate change, pose significant threats to the downstream lives and properties of people, engineering construction, and ecological environment via outburst floods, yet we currently have limited knowledge of their distribution, evolution, and the driving mechanism of rapid expansions due to the low accessibility and harsh natural conditions. By integrating optical imagery, satellite altimetry and digital elevation model (DEM), this study presents a regional-scale investigation of glacial lake dynamics across two river basins of the SETP during 1988-2013 and further explores the glacial-hydrogeomorphic process of rapidly expanding lakes. In total 1278 and 1396 glacial lakes were inventoried in 1988 and 2013, respectively. Approximately 92.4% of the lakes in 2013 are not in contact with modern glaciers, and the remaining 7.6% includes 27 (1.9%) debris-contact lakes (in contact with debris-covered ice) and 80 (5.7%) cirque lakes. In categorizing lake variations, we found that debris-contact proglacial lakes experienced much more rapid expansions (similar to 75%) than cirque lakes (similar to 7%) and non-glacier-contact lakes (similar to 3%). To explore the cause of rapid expansion for these debris-contact lakes, we further investigated the mass balance of parent glaciers and elevation changes in lake surfaces and debris-covered glacier tongues using time-series Landsat images, ICESat altimetry, and DEM. Results reveal that the upstream expansion of debris-contact proglacial lakes was not directly associated with rising water levels but with a geomorphological alternation of upstream lake basins caused by melting-induced debris subsidence at glacier termini. This suggests that the hydrogeomorphic process of glacier thinning and retreat, in comparison with direct glacial meltwater alone, may have played a dominant role in the recent glacial lake expansion observed across the SETP. Our findings assist in understanding the expansion mechanism of debris contact proglacial lakes, which facilitates early recognition of potential glacial lake hazards in this region. (C) 2016 Elsevier B.V. All rights reserved.

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