Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011
Abstract. The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To overcome the lack of region-wide mass balance data, we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo-imagery for 8 sites spread from Pamir to eastern Himalaya. The region-wide glacier mass balances were contrasted during the last decade, with moderate mass losses in eastern and central Himalaya (−0.21 ± 0.10 m yr−1 w.e. to −0.29 ± 0.09 m yr−1 w.e.) and larger losses in western Himalaya (−0.41 ± 0.11 m yr−1 w.e.). Recently reported slight mass gain of glaciers in central Karakoram is confirmed for a larger area (+0.10 ± 0.19 m yr−1 w.e.) and, new, also observed for glaciers in western Pamir (+0.14 ± 0.10 m yr−1 w.e.). We propose that the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers is estimated at −0.12 ± 0.06 m yr−1 w.e. In contrast to Indus, the relative glacier imbalance contribution to Brahmaputra and Ganges discharges is higher than previously modeled glacier seasonal contribution.