Heterogeneity in Karakoram glacier surges

Journal of Geophysical Research F: Earth Surface - Tập 120 Số 7 - Trang 1288-1300 - 2015
Duncan J. Quincey1, Neil F. Glasser2, Simon J. Cook3, Adrian Luckman4
1School of Geography, University of Leeds, Leeds, UK
2Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, UK
3Division of Geography and Environmental Management, Manchester Metropolitan University, Manchester, UK
4Department of Geography, College of Science, Swansea University, Swansea, UK

Tóm tắt

AbstractMany Karakoram glaciers periodically undergo surges during which large volumes of ice and debris are rapidly transported downglacier, usually at a rate of 1–2 orders of magnitude greater than during quiescence. Here we identify eight recent surges in the region and map their surface velocities using cross‐correlation feature tracking on optical satellite imagery. In total, we present 44 surface velocity data sets, which show that Karakoram surges are generally short‐lived, lasting between 3 and 5 years in most cases, and have rapid buildup and relaxation phases, often lasting less than a year. Peak velocities of up to 2 km a−1 are reached during summer months, and the surges tend to diminish during winter months. Otherwise, they do not follow a clearly identifiable pattern. In two of the surges, the peak velocity travels down‐ice through time as a wave, which we interpret as a surge front. Three other surges are characterized by high velocities that occur simultaneously across the entire glacier surface, and acceleration and deceleration are close to monotonic. There is also no consistent seasonal control on surge initiation or termination. We suggest that the differing styles of surge can be partly accounted for by individual glacier configurations and that while some characteristics of Karakoram surges are akin to thermally controlled surges elsewhere (e.g., Svalbard), the dominant surge mechanism remains unclear. We thus propose that these surges represent a spectrum of flow instabilities and the processes controlling their evolution may vary on a glacier by glacier basis.

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Tài liệu tham khảo

10.5194/tc-7-1385-2013

10.1038/27384

10.5194/tc-6-1251-2012

10.1038/ncomms3146

10.1029/94JB02062

10.1017/S0022143000031567

10.1139/e84-024

10.3189/172756409789624229

10.1657/1938-4246-43.4.503

10.1017/S0022143000002057

10.1029/JB092iB09p09111

10.3189/172756501781831792

10.1038/ngeo1450

10.3189/2013AoG63A495

10.3189/2014AoG66A001

10.1139/e69-106

10.1029/98EO00071

10.3189/172756507782202829

10.1007/978-94-007-6311-1

10.1017/S0022143000012429

10.1175/JCLI-D-11-00436.1

10.3189/172756501781831846

10.1038/nature11324

10.1126/science.227.4686.469

10.1109/TGRS.2004.836769

10.3189/172756403781816464

10.1016/j.rse.2007.05.019

Mason K., 1930, The glaciers of the Karakoram and neighbourhood, Geol. Surv. India, 63, 214

10.3189/002214311798043834

10.3189/2012JoG11J249

10.1139/e69-081

10.1029/2000JB900066

10.1029/2002JB001906

Owen L. A., 1989, The Karakoram glacial depositional system, Z. Geomorphol., 76, 33

10.5194/tcd-9-2597-2015

10.5194/tc-8-571-2014

10.3189/002214309790794913

10.1029/2011GL049004

10.5194/tc-8-977-2014

10.1029/JB092iB09p09121

10.1038/ngeo1068

10.3189/2013AoG63A341

10.3189/2015JoG14J174

Thông tin
Thông tin xuất bản

Journal of Geophysical Research F: Earth Surface

Tập 120 Số 7

1288-1300

Thông tin tác giả