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Upwelling of Arctic pycnocline associated with shear motion of sea ice
Author(s) -
McPhee M. G.,
Kwok R.,
Robins R.,
Coon M.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021819
Subject(s) - geology , upwelling , sea ice , pycnocline , drift ice , arctic ice pack , sea ice thickness , fast ice , wind stress , arctic , oceanography , climatology
High‐resolution radar imagery shows that the dynamic response of winter sea ice to gradients in large‐scale surface wind stress is often localized along quasi‐linear fractures hundreds of kilometers long. Relative shearing motion across these narrow fractures can exceed 10 cm s −1 . In one event recorded during the drift of the SHEBA ice camp, we observed an intense zone of pycnocline upwelling (∼14 m) associated with significant shear motion near the camp, while upward turbulent heat flux in the ocean boundary layer reached nearly 400 W m −2 , an order of magnitude greater than at any other time during the year‐long drift. We attribute the upwelling to Ekman pumping associated with concentrated ice shear. Over the entire Arctic Ocean sea ice cover, this process could be responsible for significant heat exchange between the cold surface layer and warmer subsurface water at the ubiquitous fractures resulting from large‐scale atmosphere‐ice interactions.