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Landfast Ice of Canada's Hudson Bay Region
Gagnon, A.S. and Gough, W.A. 2006. East-west asymmetry in long-term trends of landfast ice thickness in the Hudson Bay region, Canada. Climate Research 32: 177-186.

In the introductory paragraph of their recent paper on landfast ice in Canada's Hudson Bay, the authors cite nine different studies of sea-ice cover, duration and thickness in the Northern Hemisphere, noting that the Hudson Bay region "has been omitted from those studies with the exception of Parkinson et al. (1999)," which makes one wonder why.

What was done
For 13 stations located on the shores of Hudson Bay (7) and surrounding nearby lakes (6), Gagnon and Gough analyzed long-term weekly measurements of ice thickness and associated weather conditions that began and ended, in the mean, in 1963 and 1993, respectively.

What was learned
The two researchers report that "statistically significant thickening of the ice cover over time was detected on the western side of Hudson Bay, while a slight thinning lacking statistical significance [our italics] was observed on the eastern side." This asymmetry, in their words, was "related to the variability of air temperature, snow depth, and the dates of ice freeze-up and break-up," with "increasing maximum ice thickness at a number of stations" being "correlated to earlier freeze-up due to negative temperature trends in autumn," and with high snow accumulation being associated with low ice thickness, "because the snow cover insulates the ice surface, reducing heat conduction and thereby ice growth."

What it means
Noting that their findings "are in contrast to the projections from general circulation models, and to the reduction in sea-ice extent and thickness observed in other regions of the Arctic," Gagnon and Gough say "this contradiction must be addressed in regional climate change impact assessments," rather, we would add, than simply being ignored.

Parkinson, C.L., Cavalieri, D.J., Gloersen, P., Zwally, J. and Comiso, J.C. 1999. Arctic sea ice extent, areas, and trends, 1978-1996. Journal of Geophysical Research 104: 20,837-20,856.

Reviewed 4 April 2007