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Climatic control on the peak discharge of glacier outburst floods

Ng, F.S.L., Liu, S., Mavlyudov, B. and Wang, Y. (2007) Climatic control on the peak discharge of glacier outburst floods. Geophysical Research Letters, 34 (21). Art no.L21503 . ISSN 0094-8276


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Lakes impounded by natural ice dams occur in many glacier regions. Their sudden emptying along subglacial paths can unleash similar to 1 km(3) of floodwater, but predicting the peak discharge of these subglacial outburst floods ('jokulhlaups') is notoriously difficult. To study how environmental factors control jokulhlaup magnitude, we use thermo- mechanical modelling to interpret a 40- year flood record from Merzbacher Lake in the Tian Shan. We show that the mean air temperature during each flood modulates its peak discharge, by influencing both the rate of meltwater input to the lake as it drains, and the lake- water temperature. The flood devastation potential thus depends sensitively on weather, and this dependence explains how regional climatic warming drives the rising trend of peak discharges in our dataset. For other subaerial ice- dammed lakes worldwide, regional warming will also promote higher- impact jokulhlaups by raising the likelihood of warm weather during their occurrence, unless other factors reduce lake volumes at flood initiation to outweigh this effect.

Item Type: Article
Copyright, Publisher and Additional Information: © 2007 American Geophysical Union. Reproduced in accordance with the publisher's self-archiving policy.
Keywords: Jokulhlaups; Reanalysis; Magnitude; Lake
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield)
Depositing User: Miss Anthea Tucker
Date Deposited: 14 Dec 2010 09:20
Last Modified: 10 Jun 2014 01:27
Published Version: http://dx.doi.org/10.1029/2007GL031426
Status: Published
Publisher: American Geophysical Union
Refereed: Yes
Identification Number: 10.1029/2007GL031426
URI: http://eprints.whiterose.ac.uk/id/eprint/42720

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