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Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic

Publication ,  Journal Article
Petit, T; Lozier, MS; Josey, SA; Cunningham, SA
Published in: Ocean Science
October 5, 2021

Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air-sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the densification of surface water. More precisely, we study the impact of air-sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that "pre-conditions"dense water formation downstream. Analyses using 40 years of observations (1980-2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes. Our study shows that the latter explains ∼30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density in SPMW transformation partly explains the unusually large SPMW transformation in winter 2014-2015 over the Iceland Basin.

Duke Scholars

Published In

Ocean Science

DOI

EISSN

1812-0792

ISSN

1812-0784

Publication Date

October 5, 2021

Volume

17

Issue

5

Start / End Page

1353 / 1365

Related Subject Headings

  • Oceanography
  • 3708 Oceanography
  • 0405 Oceanography
 

Citation

APA
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ICMJE
MLA
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Petit, T., Lozier, M. S., Josey, S. A., & Cunningham, S. A. (2021). Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic. Ocean Science, 17(5), 1353–1365. https://doi.org/10.5194/os-17-1353-2021
Petit, T., M. S. Lozier, S. A. Josey, and S. A. Cunningham. “Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic.” Ocean Science 17, no. 5 (October 5, 2021): 1353–65. https://doi.org/10.5194/os-17-1353-2021.
Petit T, Lozier MS, Josey SA, Cunningham SA. Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic. Ocean Science. 2021 Oct 5;17(5):1353–65.
Petit, T., et al. “Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic.” Ocean Science, vol. 17, no. 5, Oct. 2021, pp. 1353–65. Scopus, doi:10.5194/os-17-1353-2021.
Petit T, Lozier MS, Josey SA, Cunningham SA. Role of air-sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic. Ocean Science. 2021 Oct 5;17(5):1353–1365.

Published In

Ocean Science

DOI

EISSN

1812-0792

ISSN

1812-0784

Publication Date

October 5, 2021

Volume

17

Issue

5

Start / End Page

1353 / 1365

Related Subject Headings

  • Oceanography
  • 3708 Oceanography
  • 0405 Oceanography