University of Cambridge > Talks.cam > Scott Polar Research Institute - Physical Sciences Seminar > Modelling ice-ocean interaction at Greenland’s tidewater glaciers

Modelling ice-ocean interaction at Greenland’s tidewater glaciers

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Observations of the mass balance of the Greenland Ice Sheet over recent decades have shown significant losses at the coastal margins, much of which has been attributed to the thinning, speed-up and retreat of tidewater glaciers. The synchronous and widespread nature of these changes is indicative of a common climatic forcing, and due to a roughly simultaneous subsurface warming of the ocean around Greenland, the ocean is the leading candidate for driving the changes observed at marine-terminating glaciers around Greenland. However the processes by which the ocean interacts with these glaciers are poorly understood, severely hampering efforts to project glacier behaviour into the future and ultimately to predict Greenland’s future contribution to sea level rise. Here, we take an ocean modelling approach to exploring the processes by which the ocean interacts with tidewater glaciers. We use both a simple theoretical model (buoyant plume theory) and a complex numerical model (MITgcm) to explore controls on submarine melt rates at tidewater glaciers, identifying fjord stratification, subglacial discharge and subglacial hydrology as the key variables which determine the rate and pattern of submarine melting. Of the three variables, subglacial hydrology is the least understood and we describe a novel attempt to constrain subglacial hydrology at Kangiata Nunata Sermia, a large tidewater glacier in southwest Greenland. We finally consider the effect of submarine melting on glacier dynamics by implementing a tidewater glacier as a moving boundary within MITgcm. Results show melt undercutting of the calving front which may drive calving and glacier dynamics at smaller tidewater glaciers. However at large tidewater glaciers this process may not proceed sufficiently quickly to influence glacier dynamics, suggesting we need to consider other processes to explain the recent changes observed at Greenland’s largest and fastest flowing tidewater glaciers.

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

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