Why Is the Sea Ice Melting so Fast? Improving Understanding of Melt Processes on First-Year Arctic Sea Ice

The area of summer sea ice in the Arctic has been decreasing since satellite observations started in 1979, and the area of ice lost in summer during the last five years is far beyond what was predicted by climate models. Furthermore there has been a shift from thicker multi-year ice to thinner first-year ice. Solar heating and other radiative processes might be important factors explaining the minima in perennial Arctic ice extent. Part of the reason for the models' inability to accurately predict the sea -ice decline is due to their overly simplistic sea-ice parameterizations,. This collaboration will bring together sea-ice scientists from three leading polar research centers in the USA and from two in Norway to investigate the processes that have import ant effects on the albedo and energy balance of sea ice, with the goal of understanding how they affect mass-balance changes during spring melt. By working together on collaborative field campaigns in spring 2010 and 2011 in Ny-Ålesund and Barrow, the gro ups involved will make measurements of physical and optical properties of first-year sea ice over representative areas throughout the melt season. These measurements will be used to better understand the melt processes for first-year sea ice, which will d ominate the Arctic in the future, and improve observation techniques by sharing experiences and methods. These investigations will lead to recommendations for how to improve the parameterizations used to represent these processes in models, so we plan to end the project with an international workshop to bring together the participants in this collaboration with other scientists making similar measurements and with leading scientists working on the sea-ice parameterizations in climate models. This workshop will produce a realistic plan for improving these parameterizations with the goal of improving future predictions of the Arctic sea-ice cover in a changing climate.