Bibliographic Details
| Title: |
Slantwise Convection in the Irminger Sea. |
| Authors: |
Le Bras, I. A.‐A.1 (AUTHOR) ilebras@whoi.edu, Callies, J.2 (AUTHOR), Straneo, F.3 (AUTHOR), Biló, T. C.3 (AUTHOR), Holte, J.3 (AUTHOR), Johnson, H. L.4 (AUTHOR) |
| Source: |
Journal of Geophysical Research. Oceans. Oct2022, Vol. 127 Issue 10, p1-15. 15p. |
| Subject Terms: |
*Ocean convection, *Atmosphere, Buoyancy, Oceanic mixing, Transfer (Law), Atmospheric models, Mixing height (Atmospheric chemistry) |
| Abstract: |
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. Plain Language Summary: The deep ocean is an important part of the climate system, as it stores carbon dioxide and heat away from the atmosphere for hundreds to thousands of years. The transfer of properties between the atmosphere and deep ocean is broadly thought to occur in mixed layers formed by cooling at high‐latitudes. Here we suggest that winds blowing in the same direction as ocean currents can trigger slantwise convection, which causes properties to be mixed to several times the conventionally defined mixed layer depth. We hypothesize that slantwise convection is active in the Irminger Sea as well as in western boundary currents across the subpolar North Atlantic region. Representing slantwise convection in ocean and climate models may be an important component of reproducing pathways into the deep ocean. Key Points: Down‐front wind buoyancy forcing is stronger than heat loss buoyancy forcing in the western Irminger SeaWe observe a subsurface ocean response to down‐front winds consistent with slantwise convectionSlantwise convection may mix waters to several times the conventionally defined mixed layer depth in this region [ABSTRACT FROM AUTHOR] |
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| Database: |
GreenFILE |
