Climate change scenarios for Hudson Bay, Canada, from general circulation models

Two generations of a climate model are compared using the impact of a CO2 doubling on the Hudson Bay region as the means of diagnosing differences in model performance. Surface temperature, precipitation, sea-ice coverage, and permafrost distribution are compared. The most striking difference is the response of the sea ice in the two models. In the coupled atmosphere-ocean climate model, sea ice virtually disappears in Hudson Bay. This leads to a substantially higher regional temperature response. We suggest that conductivity of sea ice and thermal diffusivity of seawater are key factors that cause the difference in sea-ice response. It is recommended that a regional model be developed to produce more representative climate change scenarios for the Hudson Bay region.