ABSTRACT Existing long-term metocean-ice data sets are reviewed and analyzed for estimation of trends and changes relevant to offshore oil and gas and shipping/navigation activities in the Canadian Beaufort Sea (CBS).
An analysis of 45 years (1968–2012) of sea ice properties from Canadian Ice Service sea ice charts indicates that the summer and early fall concentrations of sea ice are decreasing by up to 7.4% per decade (September to mid-October). Old ice concentrations are decreasing at a higher rate along the slope and deeper offshore waters of the Beaufort Sea at rates of 10.5% per decade. There is also evidence of an increasing presence of glacial ice features passing through the Canadian Beaufort Sea. In contrast to the deeper offshore waters, the reductions in ice concentrations over the continental slope are smaller but still statistically significant in some subregions. The mid-outer shelf region also exhibits substantial reductions in mid-October with the loss of old ice and young ice being a large part of the total ice reduction. However, there have been no significant changes observed in ice thickness in continental shelf region. The duration of the landfast ice off the coastline of the CBS is also being reduced with a delay in formation date of 2.8 weeks per decade and an advance in break-up date of 0.65 week per decade.
An analysis of long-term air temperatures reveals that the largest warming occurs in the fall and winter corresponding to a temperature elevation of about 4°C over the past five decades or an equivalent rate of decadal change of, approximately, 0.8°C. The regional wind patterns in the region exhibit little evidence of long-term trends in coastal zones, while cyclonic activity appears to be increasing in offshore areas. The combination of the reduced areal extent of sea ice in summer and especially in the fall, and continuing and perhaps increased cyclonic activity in offshore areas, is leading to increasing occurrences of large ocean waves, as seen through analyses of moored upward looking sonar data obtained over the past decade.