Influence of sea ice decline, atmospheric warming, and glacier width on marine-terminating outlet glacier behavior in northwest Greenland at seasonal to interannual timescales

Abstract

Discharge from marine-terminating outlet glaciers represents a key component of the Greenland Ice Sheet mass budget and observations suggest that mass loss from northwest Greenland has recently accelerated. Despite this, the factors controlling outlet glacier dynamics within this region have been comparatively poorly studied. Here we use remotely sensed data to investigate the influence of atmospheric, oceanic, and glacier-specific controls on the frontal position of Alison Glacier (AG), northwest Greenland, and nine surrounding outlet glaciers. AG retreated by 9.7 km between 2001 and 2005, following at least 25 years of minimal change. Results suggest that sea ice and air temperatures influence glacier frontal position at seasonal and interannual timescales. However, the response of individual outlet glaciers to forcing was strongly modified by factors specific to each glacier, specifically variations in fjord width and terminus type. Overall, our results underscore the need to consider these factors in order to interpret recent rapid changes and predict the dynamic response of marine-terminating outlet glaciers to atmospheric and oceanic forcing.