Do Greenland's outlet glaciers care about the ocean and viceversa?



Fiamma Straneo



Abstract:

The unexpected and widespread acceleration of outlet glaciers in Greenland over the last decade has contributed to a doubling of the ice sheet's contribution to sea level rise. The mechanisms behind the acceleration are unclear but there is increasing evidence that warming of ocean waters coming in contact with the glaciers may have played a role. This, in turn, would imply that the ocean can impact the variability of the Greenland Ice Sheet on decadal timescales. Regardless of the ocean's role in triggering the recent glaciers' acceleration - ocean-driven melting at the ice sheet's margins has recently emerged as a significant term in the ice sheet's mass balance. Yet our understanding of the oceanic, atmospheric and glaciological processes controlling the properties of the waters reaching the glaciers and their variability is limited and this physics is either absent or crudely represented in ice sheet, glacier and climate models. Here, I will present recent observations from several major glacial fjords systems in East Greenland (some which have recently accelerated and some which have not) and discuss the first order dynamics that have emerged from these surveys. Amongst the relevant processes - I will argue that outlet glaciers are sensitive to the variability of both Arctic and Atlantic waters circulating around Greenland as well as synoptic weather systems which modulate the fjord/shelf exchange. Finally, I will argue that the shape of terminus, and hence the stability, of Greenland's glaciers is strongly controlled by large scale ocean circulation.

Background Reading:



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Rapid Circulation of warm subtropical waters in a major glacial fjord off East Greenland, F. Straneo et al., Nature Geoscience , 2010, 10.1038/NGEO764.

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