Karakoram geodetic glacier mass balances between 2008 and 2016: persistence of the anomaly and influence of a large rock avalanche on Siachen Glacier

• Published in: Journal of Glaciology
• Main Authors: ETIENNE BERTHIER, FANNY BRUN
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2019
• Subjects: glacier mass balance; glacier surges; mountain glaciers; remote sensing; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Geodetic Glacier; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2019.32; https://doaj.org/article/015f086c36ff4c2d8b922cc5f38c3036

Karakoram glaciers experienced balanced or slightly positive mass budgets since at least the 1970s. Here, we provide an update on the state of balance of Central and Eastern Karakoram glaciers (12 000 km2) between 2008 and 2016 by differencing DEMs derived from satellite optical images. The mass budget of Central Karakoram glaciers was slightly positive (0.12 ± 0.14 m w.e. a−1) while eastern Karakoram glaciers lost mass (−0.24 ± 0.12 m w.e. a−1). The glacier-wide mass balances of surge-type and nonsurge-type glaciers were not statistically different. Our elevation change data also depict the effect of a > 100 Mm3 rock avalanche on Siachen Glacier ablation area in September 2010. It covered a 4 km2 area with a thick debris layer that unexpectedly, led to locally enhanced glacier mass loss during the following years. Enhanced melt opened a > 100 m deep 2 km2 depression and contributed to 6% of the mass loss of Siachen Glacier from 2010 to 2016 (−0.39 m w.e. a−1). We hypothesize that sub- or englacial melt may be responsible for this intriguing behaviour. This study contributes to a better knowledge of the regional pattern of the Karakoram anomaly and of the influence of rock avalanches on glacier mass changes.