A spatially resolved estimate of High Mountain Asia glacier mass balances from 2000 to 2016

Abstract

High Mountain Asia hosts the largest glacier concentration outside the polar regions. These glaciers are important contributors to streamflow in one of the most populated areas of the world. Past studies have used methods that can only provide regionally-averaged glacier mass balances to assess the High Mountain Asia glacier contribution to rivers and sea level rise. Here we compute the mass balance for about 92 % of the glacierized area of High Mountain Asia using time series of digital elevation models derived from satellite stereo-imagery. We calculate an average region-wide mass balance of -16.3 ± 3.5 Gt yr-1 (-0.18 ± 0.04 m w.e. yr-1) between 2000 and 2016, which is less negative than most previous estimates. Region-wide mass balances vary from -4.0 ± 1.5 Gt yr-1 (-0.62 ± 0.23 m w.e. yr-1) in Nyainqentanglha to +1.4 ± 0.8 Gt yr-1 (+0.14 ± 0.08 m w.e. yr-1) in Kunlun, with large intra-regional variability of individual glacier mass balances (standard deviation within a region ˜0.20 m w.e. yr-1). Specifically, our results shed light on the Nyainqentanglha and Pamir glacier mass changes, for which contradictory estimates exist in the literature. They provide crucial information for the calibration of the models used for projections of future glacier response to climatic changes, models that presently do not capture the pattern, magnitude and intra-regional variability of glacier changes in High Mountain Asia.

Multi-decadal mass balance series of three Kyrgyz glaciers inferred from transient snowline observations

“…For Abramov Glacier, we find mass balances in between the results derived by Gardelle et al (2013) and Brun et al (2017) 15 based on the comparison of DEMs, overlapping within the respective uncertainty ranges. Mass changes reported by Gardelle et al (2013) are most likely too positive as SRTM C-Band penetration depth into snow Berthier et al, 2016) might have been underestimated for the cold and dry snow of accumulation areas (Dehecq et al, 2016 For Golubin Glacier, the inferred mass balance is in close agreement with the geodetic mass change reported by Bolch (2015) (Fig.…”

“…12b). Brun et al (2017) agreement between all available mass balance assessments was found (Fig. 12c).…”

“…a −1 (Aizen et al, 1997). For Golubin, mass loss was reported by and Brun et al (2017) for recent decades.…”

“…reported by different studies (Pieczonka and Bolch, 2015;Kronenberg et al, 2016;Brun et al, 2017). Summer snowfall is frequent and fresh snow can cover the entire glacier surface for several days during the melt season, significantly reducing ablation (Kronenberg et al, 2016).…”

“…We followed Brun et al (2017) for the calculation of the random error on the geodetic mass balance estimate but did not assess the systematic error.…”