Variability of Sea Ice Cover and Oceanographic Properties of the Canadian Arctic Archipelago.

Year-long moorings have been in place since August 1989 in Lancaster Sound to measure pack ice properties and oceanographic transports of the Arctic Surface Waters passing through the Canadian Arctic Archipelago (CAA). In addition, ice charts provide a thirty year time series on the inter-annual variability of mobile and land-fast pack ice conditions. The mooring time series data shows large inter-annual variability, but generally has a mayor transport peak in the summer and seasonal low in the late fall, early winter. Regression analysis with the Arctic Ocean wind field has shown that the highest correlation between the transports in Lancaster Sound is with the winds at grid location along Banks Island in the Canadian Beaufort Sea some 1000km from the mooring site. Local winds thus do not cause the variability in transports; instead the far-field winds do. The north-south winds over the shelf at the western entrance to the NW Passage set up the along pressure gradient in Lancaster Sound which in turn cause the variability seen in the observed transports. In contrast, local atmospheric conditions determine the mobile and land-fast sea ice cover variability in Lancaster Sound. Expected atmospheric changes within the CAA due to global warming will increase the length of the mobile ice season, increase the oceanographic transport variability and thereby changing physical environments controlling the biological marine ecosystem of the CAA from an ice-algae driven benthic to a phytoplankton driven pelagic community.