Factors controlling the accelerated expansion of Imja Lake, Mount Everest region, Nepal

• Published in: Annals of Glaciology
• Main Authors: Thakuri, Sudeep, Salerno, Franco, Bolch, Tobias, Guyennon, Nicolas, Tartari, Gianni
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Climate change; Glacier flow; Glacier hazards; Mountain glaciers; Remote sensing; Annals of Glaciology
• Online Access: https://risweb.st-andrews.ac.uk/portal/en/researchoutput/factors-controlling-the-accelerated-expansion-of-imja-lake-mount-everest-region-nepal(56d57b96-357c-4a41-801c-5e5ec4f22c91).html; https://doi.org/10.3189/2016AoG71A063; https://research-repository.st-andrews.ac.uk/bitstream/10023/17281/1/Bolch_2016_AoG_FactorsControllingAccExp_CCBY_VoR.pdf

This study explores the link between area increase of Imja Tsho (Lake) and changes of Imja Glacier (area ∼25km 2 ) under the influence of climate change using multitemporal satellite imagery and local climate data. Between 1962 and 2013, Imja Lake expanded from 0.03±0.01 to 1.35±0.05 km 2 at a rate of 0.026±0.001 km 2 a -1 . The mean glacier-wide flow velocity was 37±30ma -1 during 1992-93 and 23±15ma -1 during 2013-14, indicating a decreasing velocity. A mean elevation change of -1.29±0.71ma -1 was observed over the lower part of the glacier in the period 2001-14, with a rate of -1.06±0.63ma -1 in 2001-08 and -1.56±0.80ma -1 in 2008-14. We conclude that the decrease in flow velocity is mainly associated with reduced accumulation due to a decrease in precipitation during the last few decades. Furthermore, glacier ablation has increased due to increasing maximum temperatures during the post-monsoon months. Decreased glacier flow velocities and increased mass losses induce the formation and subsequent expansion of glacial lakes under favourable topographic conditions.