Tides modulate crevasse opening prior to amajor calving event at Bowdoin Glacier, Northwest Greenland
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Date
2020-02
Publication Type
Journal Article
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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.
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published
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Journal / series
Volume
66 (255)
Pages / Article No.
113 - 123
Publisher
International Glaciological Society
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Subject
crevasses; glacier monitoring; glacier modelling; iceberg calving
Organisational unit
09558 - Walter, Fabian (ehemalig) / Walter, F. ((former))
Notes
Funding
153179 - Dynamic changes of tidewater outlet glaciers: Bowdoin glacier, Northwest Greenland (SNF)