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Biogeochemical impact of snow cover and cyclonic intrusions on the winter Weddell Sea ice pack

Citation

Tison, J-L and Schwegmann, S and Dieckmann, G and Rintala, J-M and Meyer, H and Moreau, S and Vancoppenolle, M and Nomura, D and Engberg, S and Bloomster, LJ and Heindricks, S and Uhlig, C and Luhtanen, A-M and de Jong, J and Janssens, J and Carnat, G and Zhou, J and Delille, B, Biogeochemical impact of snow cover and cyclonic intrusions on the winter Weddell Sea ice pack, Journal of Geophysical Research: Oceans pp. 1-37. ISSN 2169-9275 (In Press) [Refereed Article]


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DOI: doi:10.1002/2017JC013288

Abstract

Sea ice is a dynamic biogeochemical reactor and a double interface actively interacting with both the atmosphere and the ocean. However, proper understanding of its annual impact on exchanges, and therefore potentially on the climate, notably suffer from the paucity of autumnal and winter data sets. Here we present the results of physical and biogeochemical investigations on winter Antarctic pack ice in the Weddell Sea (R.V. Polarstern AWECS cruise, July-August 2013) which are compared with those from two similar studies conducted in the area in 1986 and 1992.

The winter 2013 was characterized by a warm sea ice cover due to the combined effects of deep snow and frequent warm cyclones events penetrating southwards from the open Southern Ocean. These conditions were favorable to high ice permeability and cyclic events of brine movements within the sea ice cover (brine tubes), favoring relatively high chlorophyll-a (Chl-a) concentrations. We discuss the timing of this algal activity showing that arguments can be presented in favor of continued activity during the winter due to the specific physical conditions. Large-scale sea ice model simulations also suggest a context of increasingly deep snow, warm ice and large brine fractions across the three observational years, despite the fact that the model is forced with a snowfall climatology. This lends support to the claim that more severe Antarctic sea ice conditions, characterized by a longer ice season, thicker and more concentrated ice are sufficient to increase the snow depth and, somehow counter-intuitively, to warm the ice.

Item Details

Item Type:Refereed Article
Keywords:sea ice biogeochemistry, snow cover, winter, Weddell Sea
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Mathematical Sciences
Author:Moreau, S (Dr Sebastien Moreau)
Author:Janssens, J (Miss Julie Janssens)
ID Code:122292
Year Published:In Press
Deposited By:Centre for Ecology and Biodiversity
Deposited On:2017-11-08
Last Modified:2017-11-09
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