Slantwise convection in the Irminger Sea

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Le Bras, Isabela A.‐A.
Callies, Jörn
Straneo, Fiammetta
Biló, Tiago C.
Holte, James
Johnson, Helen L.
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The subpolar North Atlantic is a site of significant carbon dioxide, oxygen, and heat exchange with the atmosphere. This exchange, which regulates transient climate change and prevents large‐scale hypoxia throughout the North Atlantic, is thought to be mediated by vertical mixing in the ocean's surface mixed layer. Here we present observational evidence that waters deeper than the conventionally defined mixed layer are affected directly by atmospheric forcing in this region. When northerly winds blow along the Irminger Sea's western boundary current, the Ekman response pushes denser water over lighter water, potentially triggering slantwise convection. We estimate that this down‐front wind forcing is four times stronger than air–sea heat flux buoyancy forcing and can mix waters to several times the conventionally defined mixed layer depth. Slantwise convection is not included in most large‐scale ocean models, which likely limits their ability to accurately represent subpolar water mass transformations and deep ocean ventilation.
Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 127(10), (2022): e2022JC019071,
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Le Bras, I., Callies, J., Straneo, F., Biló, T., Holte, J., & Johnson, H. (2022). Slantwise convection in the Irminger Sea. Journal of Geophysical Research: Oceans, 127(10), e2022JC019071.
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