University of Cambridge > > Scott Polar Research Institute - Physical Sciences Seminar > Controls on the stability of Greenland’s tidewater glaciers: the impact of runoff on fjord circulation and termini melt rates

Controls on the stability of Greenland’s tidewater glaciers: the impact of runoff on fjord circulation and termini melt rates

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If you have a question about this talk, please contact Poul Christoffersen.

Observations suggest that oceanic warming may cause phases of rapid retreat and acceleration at Greenland’s marine-terminating outlet glaciers, significantly increasing the rate of mass loss from the ice sheet. In this scenario, retreat may be triggered by increased submarine melting at the glacier termini. Due to the inaccessibility of this submarine environment however, little is known about the rate of melting or how it is influenced by oceanic and atmospheric processes. This seminar will focus on the potential role of meltwater runoff from these glaciers in stimulating submarine melting. Firstly, a high resolution general circulation model (MITgcm) is used to explore the role of near-terminus hydrology on submarine melt rate. It has been shown previously that freshwater input increases melting by driving a vigorous upwelling circulation; we find that the importance of this process is strongly dependent on the subglacial drainage morphology, with more distributed drainage systems driving dramatically higher melt rates. We then explore the influence of glacial runoff on the wider circulation of the fjords. Through simulation of Kangerdlugssuaq Fjord, east Greenland, we find that this freshwater input drives a strong, two-celled overturning circulation capable of transporting warm ocean waters to the fjord head on sub-seasonal timescales. This circulation may play a significant role in maintaining the connection between the ocean and the ice sheet, permitting glaciers to respond rapidly to changing ocean properties despite long and complex fjord systems.

This talk is part of the Scott Polar Research Institute - Physical Sciences Seminar series.

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