Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011
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 estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (−0.22 ± 0.12 m w.e. yr −1 to −0.33 ± 0.14 m w.e. yr −1) and larger losses in the western Himalaya (−0.45 ± 0.13 m w.e. yr −1). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10 ± 0.16 m w.e. yr −1) and also observed for glaciers in the western Pamir (+0.14 ± 0.13 m w.e. yr −1). Thus, the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, −0.14 ± 0.08 m w.e. yr −1, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st century.