Coupled sea-ice/ocean numerical simulations of the Bering Sea for the period 1996-2003.

Enrique Curchitser, Albert Hermann, Kate Hedstrom and Paul Budgell

A coupled, regional sea-ice/ocean model has been developed to examine the interannual variability of circulation, sea ice extent, thickness and concentration within the Bering Sea for the period 1996-2003. In particular we examine the variability induced by the 1997/1998 El Nino, and the post-1999 cool phase in the Northeast Pacific. Our coupled model is based on the Regional Ocean Modeling System (ROMS), implemented at 10 km resolution for a Northeast Pacific domain which includes the Gulf of Alaska and the Bering Sea. The regional model is embedded in a lower resolution basin-scale model, which is used to generate the large-scale signals and provides both boundary and initial conditions for the Bering Sea via one-way nesting. Ice dynamics are based on the efficient elastic-viscous-plastic rheology of Hunke and Dukowicz (1997); ice thermodynamics are based upon Mellor and Kantha (1989) and include a three level ice layer, a snow layer, and a molecular sub-layer at the ice/ocean interface. Atmospheric forcing is derived from NCEP Reanalysis fluxes, corrected for model sea surface temperature and sea ice concentration. Regional model results are compared with satellite derived products based upon Pathfinder SSM/I and sea surface temperature. We further compare interannual patterns of the Bering with those of the Barents/Norwegian Seas, derived from ongoing, ROMS-based,sea-ice/ocean modeling of that region.