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Surge dynamics and lake outbursts of Kyagar Glacier, Karakoram

Round, Vanessa and Leinss, Silvan and Huss, Matthias and Haemmig, Christoph and Hajnsek, Irena (2017) Surge dynamics and lake outbursts of Kyagar Glacier, Karakoram. The Cryosphere, 11 (2), pp. 723-739. Copernicus Publications. doi: 10.5194/tc-11-723-2017. ISSN 1994-0416.

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Abstract

The recent surge cycle of Kyagar Glacier, in the Chinese Karakoram, caused formation of an ice-dammed lake and subsequent glacial lake outburst floods (GLOFs) exceeding 40 million m3 in 2015 and 2016. GLOFs from Kyagar Glacier reached double this size in 2002 and earlier, but the role of glacier surging in GLOF formation was previously unrecognised. We present an integrative analysis of the glacier surge dynamics from 2011 to 2016, assessing surge mechanisms and evaluating the surge cycle impact on GLOFs. Over 80 glacier surface velocity fields were created from TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement), Sentinel-1A, and Landsat satellite data. Changes in ice thickness distribution were revealed by a time series of TanDEM-X elevation models. The analysis shows that, during a quiescence phase lasting at least 14 years, ice mass built up in a reservoir area at the top of the glacier tongue, and the terminus thinned by up to 100 m, but in the 2 years preceding the surge onset this pattern reversed. The surge initiated with the onset of the 2014 melt season, and in the following 15 months velocity evolved in a manner consistent with a hydrologically controlled surge mechanism. Dramatic accelerations coincided with melt seasons, winter deceleration was accompanied by subglacial drainage, and rapid surge termination occurred following the 2015 GLOF. Rapid basal motion during the surge is seemingly controlled by high water pressure, caused by input of surface water into either an inefficient subglacial drainage system or unstable subglacial till. The potential lake volume increased to more than 70 million m3 by late 2016, as a result of over 60 m of thickening at the terminus. Lake formation and the evolution of the ice dam height should be carefully monitored through remote sensing to anticipate large GLOFs in the near future.

Item URL in elib:https://elib.dlr.de/118509/
Document Type:Article
Title:Surge dynamics and lake outbursts of Kyagar Glacier, Karakoram
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Round, VanessaETH Zurich / Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)UNSPECIFIED
Leinss, SilvanETH ZurichUNSPECIFIED
Huss, MatthiasETH Zurich / University of Fribourg, SwitzerlandUNSPECIFIED
Haemmig, ChristophGEOTEST AG, SwitzerlandUNSPECIFIED
Hajnsek, IrenaETH Zurich / German Aerospace Center (DLR)UNSPECIFIED
Date:21 March 2017
Journal or Publication Title:The Cryosphere
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:11
DOI :10.5194/tc-11-723-2017
Page Range:pp. 723-739
Publisher:Copernicus Publications
ISSN:1994-0416
Status:Published
Keywords:Kyagar Glacier, TanDEM-X, combined optical data and synthetic aper- ture radar (SAR) satellite data
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Projekt TanDEM-X (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Microwaves and Radar Institute > Radar Concepts
Deposited By: Hajnsek, Dr.rer.nat. Irena
Deposited On:26 Jan 2018 09:42
Last Modified:09 Jan 2019 12:23

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