Seasonal Sea Ice Loss in Eastern Greenland

Arctic sea ice loss continues to serve as a strong gauge of climate change. Here we evaluate long term trends in sea ice coverage along the east Greenland coast, between Fram Strait and Cape Farewell, from 1979 to present. Unlike for the Arctic Ocean, where the most pronounced decline is that of the summer time sea ice minimum, along the northeast Greenland shelf, we find that the most pronounced decline occurs during winter (even as the summertime decline is also significant). In this study, we investigate the potential drivers of the wintertime sea-ice reduction in a region where sea-ice cover is largely due to advection – as opposed to local formation. Using climate reanalysis products and satellite sea surface temperature measurements, we find a warming of Atlantic Water entering the region by ~1.2^o C over the same time period. Over this period there is also an apparent constant Fram Strait volume export, driven by a thinning that approximately balances the increased ice area export. Next we use a simplified box model to investigate the hypothesis that warming the Atlantic Waters on the shelf may be a dominant driver of sea-ice melt. This is based on the mean ice area export adding a representative thickness and extracting the mixed layer thickness from hydrographic profiles. A representative mean and anomaly heat budget for the Greenland Sea and Irminger Basin sea ice over the last 40 years is thus created, explaining much of the observed winter ice loss.