The Impact of Refreezing of Melt Ponds on Arctic Sea Ice Thinning

Abstract:

The presence of melt ponds over the sea ice cover in the Arctic has a profound impact on the surface albedo inducing a positive feedback leading to sea ice thinning.

At the end of summer the melt ponds, covering a large fraction of the sea ice, start freezing and get trapped between the sea ice beneath and a thin surface layer of ice.

The pond water stores latent heat that is released as they freeze. Ponds trapped under a layer of refrozen ice have been observed in the Arctic and our model results, confirmed by observations, show that the latent heat stored in the ice due to their presence slows the basal sea ice growth for over a month after a sea ice lid appears on their surface.

In this work we study the ice/water temperature profile in the trapped pond system and its evolution until the pond freezes and show the impact of the presence of a trapped pond on sea ice growth. We have carried out this study by developing a three layer, one-dimensional model of temperature and salinity evolution to study the refreezing process. We show some preliminary results obtained by including this new process in the CICE model and in particular, the impact that the increased pond salinity and the refrozen pond persistence have on the sea ice basal growth.