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Tides modulate crevasse opening prior to a major calving event at Bowdoin Glacier, Northwest Greenland

Authors :
Eef van Dongen
Guillaume Jouvet
Andrea Walter
Joe Todd
Thomas Zwinger
Izumi Asaji
Shin Sugiyama
Fabian Walter
Martin Funk
Source :
Journal of Glaciology, Vol 66, Pp 113-123 (2020)
Publication Year :
2020
Publisher :
Cambridge University Press, 2020.

Abstract

Retreat of calving glaciers worldwide has contributed substantially to sea-level rise in recent decades. Mass loss by calving contributes significantly to the uncertainty of sea-level rise projections. At Bowdoin Glacier, Northwest Greenland, most calving occurs by a few large events resulting from kilometre-scale fractures forming parallel to the calving front. High-resolution terrestrial radar interferometry data of such an event reveal that crevasse opening is fastest at low tide and accelerates during the final 36 h before calving. Using the ice flow model Elmer/Ice, we identify the crevasse water level as a key driver of modelled opening rates. Sea water-level variations in the range of local tidal amplitude (1 m) can reproduce observed opening rate fluctuations, provided crevasse water level is at least 4 m above the low-tide sea level. The accelerated opening rates within the final 36 h before calving can be modelled by additional meltwater input into the crevasse, enhanced ice cliff undercutting by submarine melt, ice damage increase due to tidal cyclic fatigue, crevasse deepening or a combination of these processes. Our results highlight the influence of surface meltwater and tides on crevasse opening leading to major calving events at grounded tidewater glaciers such as Bowdoin.

Details

Language :
English
ISSN :
00221430 and 17275652
Volume :
66
Database :
Directory of Open Access Journals
Journal :
Journal of Glaciology
Publication Type :
Academic Journal
Accession number :
edsdoj.9a9d6befa99b448ca3cb1fc7006645dd
Document Type :
article
Full Text :
https://doi.org/10.1017/jog.2019.89