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: BERTHIER, ETIENNE, BRUN, FANNY
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2019
• Subjects: Geodetic Glacier; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/jog.2019.32; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143019000327

ABSTRACT 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 km 2 ) 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 Mm 3 rock avalanche on Siachen Glacier ablation area in September 2010. It covered a 4 km 2 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 km 2 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.