Atmospheric drivers of melt-related ice speed-up events on the Russell Glacier in southwest Greenland

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_332DEF4AC8A3
Type
Article: article from journal or magazin.
Collection
Publications
Title
Atmospheric drivers of melt-related ice speed-up events on the Russell Glacier in southwest Greenland
Journal
The Cryosphere
Author(s)
Schmid Timo, Radić Valentina, Tedstone Andrew, Lea James M., Brough Stephen, Hermann Mauro
ISSN
1994-0424
Publication state
Published
Issued date
13/09/2023
Peer-reviewed
Oui
Volume
17
Number
9
Pages
3933-3954
Language
english
Abstract
The Greenland Ice Sheet is a major contributor to current and projected sea level rise in the warming climate. However, uncertainties in Greenland's contribution to future sea level rise remain, partly due to challenges in constraining the role of ice dynamics. Transient ice accelerations, or ice speed-up events, lasting from 1 d to 1 week, have the potential to indirectly affect the mass budget of the ice sheet. They are triggered by an overload of the subglacial drainage system due to an increase in water supply. In this study, we identify melt-induced ice speed-up events at the Russell Glacier, southwest Greenland, in order to analyse synoptic patterns driving these events. The short-term speed-up events are identified from daily ice velocity time series collected from six GPS stations along the glacier for each summer (May–October) from 2009 to 2012. In total, 45 ice speed-up events are identified, of which we focus on the 36 melt-induced events, where melt is derived from two in situ observational datasets and one regional climate model forced by ERA5 reanalysis. We identify two additional potential water sources, namely lake drainages and extreme rainfall, which occur during 14 and 4 out of the 36 melt-induced events, respectively. The 36 melt-induced speed-up events occur during synoptic patterns that can be grouped into three main clusters: (1) patterns that resemble atmospheric rivers with a landfall in southwest Greenland, (2) patterns with anticyclonic blocking centred over southwest Greenland, and (3) patterns that show low-pressure systems centred either south or southeast of Greenland. Out of these clusters, the one resembling atmospheric river patterns is linked to the strongest speed-up events induced by 2 to 3 d continuously increasing surface melt driven by anomalously high sensible heat flux and incoming longwave radiation. In the other two clusters, the net shortwave radiation dominates the contribution to the melt energy. As the frequency and intensity of these weather patterns may change in the warming climate, so may the frequency and intensity of ice speed-up events, ultimately altering the mass loss of the ice sheet.
Web of science
Open Access
Yes
Create date
29/08/2024 10:03
Last modification date
22/11/2024 10:39
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