Early twenty-first century glacier mass losses in the Indus Basin constrained by density assumptions

JOURNAL OF HYDROLOGY

卷:574

Article

Muhammad, Sher^1,2  Tian, Lide^1,3,4,5  Khan, Asif^6,7,8 

[1] Yunnan Univ, Inst Int Rivers & Ecosecur, Kunming 650500, Yunnan, Peoples R China

[2] Int Ctr Integrated Mt Dev ICIMOD, GPO Box 3226, Kathmandu, Nepal

[3] Chinese Acad Sci, Key Lab Tibetan Environm Change & Land Surface Pr, Beijing 100101, Peoples R China

[4] Yunnan Univ, Yunnan Key Lab Int Rivers & Transboundary Ecosecu, Kunming 650500, Yunnan, Peoples R China

[5] Univ Chinese Acad Sci, Coll Resource & Environm, Beijing 100190, Peoples R China

[6] Univ Cambridge, Dept Engn, Trumpington St, Cambridge CB3 1PZ, England

[7] Univ Engn & Technol, Dept Civil Engn, Jalozai Campus, Peshawar, Pakistan

[8] LUMS, Water Informat Ctr, Lahore, Pakistan

关键词: Remote sensing;    Mass balance;    Density assumptions;    Indus Basin;    Karakoram;   

DOI  :  10.1016/j.jhydrol.2019.04.057

来源: Elsevier

【 摘 要 】

Glaciers in the upper Indus supply more than half of the river water, are experiencing significant melting with a debated fate. The recent melting rate is still contained by considerable uncertainties, hindering to estimate precise glacier mass change. Here we present geodetic mass balance results for the whole Indus Basin using SRTM and ALOS 30 m elevation data, improved glacier inventory, optimized glacier surface density, and validation through in-situ differential GPS and ICESat data. Our glacier inventory and derived by improving RGI6.0 boundaries and separated into debris cover and debris free parts. The derived surface elevation changes were converted into annual mass balances using separated density assumptions (four criteria) for debris-covered ice (900 +/- 60 kg m(-3)), debris-free ice (below 20 degrees and 25 degrees slopes (850 +/- 60 kg m(-3)) and above 20 degrees and 25 degrees slopes (600 +/- 60 kg m(-3))), respectively. The resulting mass balance biased between -0.20 and 0.09 m water equivalent (w.e.) a(-1) using an average (850 +/- 60 kg m(-3)) density assumption throughout the Indus Basin. In the western Himalaya and Hindu Kush, the glacier mass losses are less affected by the average density assumption compared to the Karakoram. The western (Hunza) and central (Shigar) Karakoram glaciers show negligible mass losses of -0.02 +/- 0.12 and -0.01 +/- 0.13 m w.e. a(-1) in contrast to the relatively more negative mass balance (-0.26 +/- 0.21 m w.e. a(-1)) in the eastern (Shyok) Karakoram. All the sub-basins exhibit negative mass balances, with the most negative values ranging from -0.34 +/- 0.31 to 0.44 +/- 0.27 m w.e. a(-1) in the Ravi, Chenab and Jhelum sub-basins of the Himalaya. The whole Indus Basin contributes approximately +0.014 +/- 0.016 mm a(-1) to the global mean sea-level equivalent.

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