Stewart, Andrew L. and Ferrari, Raffaele and Thompson, Andrew F. (2014) On the Importance of Surface Forcing in Conceptual Models of the Deep Ocean. Journal of Physical Oceanography, 44 (3). pp. 891-899. ISSN 0022-3670. http://resolver.caltech.edu/CaltechAUTHORS:20140425-074934016
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In the major ocean basins, diapycnal mixing upwells dense Antarctic Bottom Water, which returns southward and closes the deepest cell of the meridional overturning circulation (MOC). This cell ventilates the deep ocean and regulates the partitioning of CO2 between the atmosphere and the ocean. The oceanographic community's conceptual understanding of the deep stratification and MOC has evolved from classic “abyssal recipes” arguments to a more recent appreciation of along-isopycnal upwelling in the Southern Ocean, consistent with a weakly mixed ocean interior. Both the deep stratification and the deep MOC are shown here to be sensitive to the form of the surface buoyancy forcing in a two-dimensional model that includes a circumpolar channel and northern basin. For a fixed surface buoyancy condition, the deep stratification is essentially prescribed, whereas for a fixed surface buoyancy flux, the deep stratification varies by orders of magnitude over the range of diapycnal diffusivity κ observed in the ocean. These cases also produce different scalings for the deep MOC with κ, in both weak and strong κ regimes. In addition, these scalings are shown to be sensitive not only to the type of surface boundary condition, but also to the latitudinal structure of the surface fluxes. This latter point is crucial as buoyancy budgets and dynamical features of the circulation are poorly constrained along the Antarctic margins. This study emphasizes the need for caution in the interpretation of simple conceptual models that, while useful, may not include all mechanisms that contribute to the MOC’s strength and structure.
|Additional Information:||© 2014 American Meteorological Society. Manuscript received 26 September 2013, in final form 27 November 2013. A. L. S.’s and A. F. T.’s research was supported NSF Award OCE-1235488. R. F. acknowledges support through NSF Award OCE-1232962. The authors thank Maxim Nikurashin and two anonymous reviewers for comments that improved the manuscript.|
|Subject Keywords:||Circulation; Dynamics; Abyssal circulation; Diapycnal mixing; Eddies; Fluxes|
|Official Citation:||Stewart, Andrew L., Raffaele Ferrari, Andrew F. Thompson, 2014: On the Importance of Surface Forcing in Conceptual Models of the Deep Ocean. J. Phys. Oceanogr., 44, 891–899. doi: http://dx.doi.org/10.1175/JPO-D-13-0206.1|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||25 Apr 2014 17:24|
|Last Modified:||25 Apr 2014 17:24|
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