Greenland Melt and Climate

Recent publication by Barber et al. (2012, GRL) presented a reconstruction of the spatially distributed FW flux from Greenland for 1958–2010, showing a modest increase into the Arctic Ocean during this period. Fluxes into the Irminger Basin, however, have increased by fifty percent (6.3 ± 0.5 km³ yr⁻²) in less than twenty years. This greatly exceeds previous estimates. For the ice sheet as a whole the rate of increase since 1992 is 16.9 ± 1.8 km³ yr⁻². The cumulative FW anomaly since 1995 is 3200 ± 358 km³, which is about a third of the magnitude of the Great Salinity Anomaly (GSA) of the 1970s.  If this trend continues into the future, the anomaly will exceed that of the Great Salinity Anomaly by about 2025.  Moreover, modeling studies indicate a steady decline in the 20th Century (continuing into the 21^st) ice export through the Fram Strait while FW fluxes from Greenland are predicted to continue to increase. Thus, for the Irminger Basin, the role of Greenland FW fluxes is likely to become increasingly important.  The proximity of this region to the areas of subpolar North Atlantic deep convection adds to the broader implications of changes arising from Greenland’s freshwater fluxes to the surrounding seas. It is proposed to study the pathways of FW in the GIN Sea and the mechanisms of lateral advection of FW to the convection regions of the GIN Sea from the boundary currents. To do this, three teams (1. D. Dukhovskoy and M-L. Timmermans, USA; 2. Jean-Philippe Paquin, Canada; 3. Marie-Noelle Houssais & Christophe Herbaut, France) will employ their high resolution models, and analyze results in conjunction with ocean observations. Several years of recent atmospheric forcing and Greenland runoff will be replicated in the higher resolution model to better simulate freshwater pathways of Greenland FW flux in the Arctic Ocean and Greenland Sea. Model experiments will be conducted with tracers to assess FW pathways, residence time, and transformation of FW along its path in the GIN Sea. Atmosphere-ocean heat fluxes in these model runs will allow teams to better understand the Greenland ice sheet melt role in the future ocean circulation and climate changes (leader: D. Dukhovskoy). One more leader of this group is Chuck Green who will be focused on the analysis of freshwater impact on subarctic and mid-latitude ecosystems.