Tides modulate crevasse opening prior to amajor calving event at Bowdoin Glacier, Northwest Greenland
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. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000384152Publication status
publishedExternal links
Journal / series
Journal of GlaciologyVolume
Pages / Article No.
Publisher
International Glaciological SocietySubject
crevasses; glacier monitoring; glacier modelling; iceberg calvingOrganisational unit
09558 - Walter, Fabian (ehemalig) / Walter, F. ((former))
Funding
153179 - Dynamic changes of tidewater outlet glaciers: Bowdoin glacier, Northwest Greenland (SNF)
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