Details:

Journal Title:
Journal of Physical Oceanography
Personal Author:
Xu, Xiaobiao ; Rhines, Peter B. ; Chassignet, Eric P.
Xu, Xiaobiao ; Rhines, Peter B. ; Chassignet, Eric P. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office)
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office) Less -
Description:
Diapycnal water mass transformation is the essence behind the Atlantic meridional overturning circulation (AMOC) and the associated heat/freshwater transports. Existing studies have mostly focused on the transformation that is forced by surface buoyancy fluxes, and the role of interior mixing is much less known. This study maps the three-dimensional structure of the diapycnal transformation, both surface forced and mixing induced, using results of a high-resolution numerical model that have been shown to represent the large-scale structure of the AMOC and the North Atlantic subpolar/subtropical gyres well. The analyses show that 1) annual mean transformation takes place seamlessly from the subtropical to the subpolar North Atlantic following the surface buoyancy loss along the northward-flowing upper AMOC limb; 2) mixing, including wintertime convection and warm-season restratification by mesoscale eddies in the mixed layer and submixed layer diapycnal mixing, drives transformations of (i) Subtropical Mode Water in the southern part of the subtropical gyre and (ii) Labrador Sea Water in the Labrador Sea and on its southward path in the western Newfoundland Basin; and 3) patterns of diapycnal transformations toward lighter and denser water do not align zonally—the net three-dimensional transformation is significantly stronger than the zonally integrated, two-dimensional AMOC streamfunction (50% in the southern subtropical North Atlantic and 60% in the western subpolar North Atlantic).
Keywords:
[+]
Ocean-atmosphere Interaction Oceanography
Source:
J. Phys. Ocean. (2018) 48(10): 2233-2258
DOI:
https://doi.org/10.1175/JPO-D-17-0223.1
Document Type:
Journal Article
Funding:
Grant no. NA15OAR4310088
Place as Subject:
Atlantic Ocean
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:6be40b09cc1029837a0134ef39b4bee6d6fb45156455cdbea4cefeb0791315fd
Download URL:
https://repository.library.noaa.gov/view/noaa/28260/noaa_28260_DS1.pdf
File Type:

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