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

Eef Van Dongen*, Guillaume Jouvet, Andrea Walter, Joe Todd, Thomas Zwinger, Izumi Asaji, Shin Sugiyama, Fabian Walter, Martin Funk

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)113-123
JournalJournal of Glaciology
Volume66
Issue number255
Early online date4 Dec 2019
DOIs
Publication statusPublished - Feb 2020

Keywords

  • Crevasses
  • Glacier modelling
  • Glacier monitoring
  • Iceberg calving

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