Publication Date:
2022-05-25
Description:
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C07015, doi:10.1029/2010JC006744.
Description:
In summer on the shallow New England continental shelf, near the coast the water temperature is much cooler than the observed surface heat flux suggests. Using depth-integrated heat budgets in 12 and 27 m water depth calculated from observed surface heat flux, water temperature, and velocity, we demonstrate that on time scales of weeks to months the water is persistently cooled due to a mean upwelling circulation. Because the mean wind is weak, that mean circulation is likely not wind driven; it is partly a tidal residual circulation. A feedback exists between the cross-shelf and surface heat fluxes: the two fluxes remain nearly in balance for months, so the water temperature is nearly constant in spite of strong surface heating (the heat budget is two-dimensional). A conceptual model explains the feedback mechanism: the short flushing time of the shallow shelf produces a near steady state heat balance, regardless of the exact form of the circulation, and the feedback is via the influence of surface heating on temperature stratification. Along-shelf heat flux divergence is apparently small compared to the surface and cross-shelf heat flux divergences on time scales of weeks to months. Heat transport due to Stokes drift from surface gravity waves is substantial, warms the shallow shelf in summer, and was previously ignored. In winter, the surface heat flux dominates and the observed water temperature is close to the temperature predicted from surface cooling (the heat budget is one-dimensional); weak winter stratification makes the cross-shelf heat flux small even during strong cross-shelf circulation.
Description:
This research was
funded by National Aeronautics and Space Administration Headquarters
grant NNG04GL03G and Earth System Science Fellowship Grant
NNG04GQ14H; Woods Hole Oceanographic Institution through Academic
Programs Fellowship Funds and MVCO; National Science Foundation
grants OCE‐0241292, OCE‐0548961, and OCE‐0337892; the Jewett/
EDUC/Harrison Foundation; and Office of Naval Research contracts
N00014‐01‐1‐0029 and N00014‐05‐10090 for the Low‐Wind Component
of the Coupled Boundary Layers Air‐Sea Transfer Experiment.
Keywords:
Continental shelf
;
Heat budget
;
Inner shelf
;
Seasonal cycle
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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