Publication Date:
2022-05-26
Description:
Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 29 (2016): 8317-8331, doi:10.1175/JCLI-D-16-0109.1.
Description:
A simple analytic model is developed to represent the offshore decay of cold sea surface temperature (SST) signals that originate from wind-driven upwelling at a coastal boundary. The model couples an oceanic mixed layer to an atmospheric boundary layer through wind stress and air–sea heat exchange. The primary mechanism that controls SST is a balance between Ekman advection and air–sea exchange. The offshore penetration of the cold SST signal decays exponentially with a length scale that is the product of the ocean Ekman velocity and a time scale derived from the air–sea heat flux and the radiative balance in the atmospheric boundary layer. This cold SST signal imprints on the atmosphere in terms of both the boundary layer temperature and surface wind. Nonlinearities due to the feedback between SST and atmospheric wind, baroclinic instability, and thermal wind in the atmospheric boundary layer all slightly modify this linear theory. The decay scales diagnosed from two-dimensional and three-dimensional eddy-resolving numerical ocean models are in close agreement with the theory, demonstrating that the basic physics represented by the theory remain dominant even in these more complete systems. Analysis of climatological SST off the west coast of the United States also shows a decay of the cold SST anomaly with scale roughly in agreement with the theory.
Description:
MASwas supported by the Andrew
W. Mellon Foundation Endowed Fund for Innovative
Research and the National Science Foundation under
Grant OCE-1433170 and PLR-1415489. NS was supported
by the National Aeronautics and Space Administration
under Grant NNX14AL83G, the Department of
Energy, Office of Science Grant DE-SC0006766, and the
Japan Agency for Marine-Earth Science and Technology
as part of the JAMSTEC-IPRC Joint Investigations.
Description:
2017-05-03
Keywords:
Coastal flows
;
Ekman pumping/transport
;
Ocean dynamics
Repository Name:
Woods Hole Open Access Server
Type:
Article
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