ARCTIC Interannual Variability of Landfast Ice Thickness in the Canadian High Arctic, 1950-89
ABSTRACT. A physical one-dimensional heat transfer model of fast ice growth was used to investigate the interannual variability of maximum fast ice thickness at four sites in’the High Arctic over the period 1950-89. The insulating role of snow cover was found to be the most important factor, explain...
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| Format: | Text |
| Language: | English |
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1992
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.544.3944 http://pubs.aina.ucalgary.ca/arctic/Arctic45-3-273.pdf |
| Summary: | ABSTRACT. A physical one-dimensional heat transfer model of fast ice growth was used to investigate the interannual variability of maximum fast ice thickness at four sites in’the High Arctic over the period 1950-89. The insulating role of snow cover was found to be the most important factor, explaining 30-60 % of the variance in maximum ice thickness values. Other snaw-related processes such as slushing and density variations were esti-mated to explain a further 15-30 % of the variance. In contrast, annual variation in air temperatures explained less than 4 % of the variance in maxi-mum ice thickness. No evidence was found for the systematic ice thinning trend anticipated from greenhouse gas-induced global warming. However, recent ice thinning and thickening trends at two sites (Alert ind Resolute) are consistent with changes in the average depth of snow covering the ice and may be explained by changes in cyclone frequencies. A response surface sensitivity analysis following Fowler and de Freitas (1990) indicated the High Arctic landfast ice regime would be more sensitive to air temperature variations under a warmer, snowier environment. Key words: landfast ice, snow, interannual variability, climate change, Canadian High Arctic RESUME. On s’est servi d’un modkle physique de transfert unidimensionnel de chaleur de la croissance de la banquise catitre pour Ctudier la vari-abilitC interannuelle de I’Cpaisseur maximale de la banquise c6titre B quatre stations de l’kctique septentrional au cours de la pkriode allant de 1950 B 1989. Le r61e d’isolant de la couche de neige s’est rCvClt le facteur le plus important, rkpondant pour 30 B 60 p. 100 de 1’6cart observe dans les Cpaisseurs maximales de glace. On estime qu’une autre partie (15 B 30 p. 100) de 1’6cart dCcoule d’autres processus liCs B la neige, comme la varia-tion de la densit6 et la gadoue. En revanche, la variation annuelle des temp6ratures de l’air est intervenue pour moins de 4 p. 100 de I’Ccart observC |
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