Publication Date:
2022-05-25
Description:
Author Posting. © American Meteorological Society, 2010. 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 Physical Oceanography 40 (2010): 2679–2695, doi:10.1175/2010JPO4395.1.
Description:
Observations of stratification and currents between June 2007 and March 2009 reveal a strong overflow between 400- and 570-m depth from the Panay Strait into the Sulu Sea. The overflow water is derived from approximately 400 m deep in the South China Sea. Temporal mean velocity is greater than 0.75 m s−1 at 50 m above the 570-m Panay Sill. Empirical orthogonal function analysis of a mooring time series shows that the flow is dominated by the bottom overflow current with little seasonal variance. The overflow does not descend below 1250 m in the Sulu Sea but rather settles above high-salinity deep water derived from the Sulawesi Sea. The mean observed overflow transport at the sill is 0.32 × 106 m3 s−1. The observed transport was used to calculate a bulk diapycnal diffusivity of 4.4 × 10−4 m2 s−1 within the Sulu Sea slab (575–1250 m) ventilated from Panay Strait. Analysis of Froude number variation across the sill shows that the flow is hydraulically controlled. A suitable hydraulic control model shows overflow transport equivalent to the observed overflow. Thorpe-scale estimates show turbulent dissipation rates up to 5 × 10−7 W kg−1 just downstream of the supercritical to subcritical flow transition, suggesting a hydraulic jump downstream of the sill.
Description:
This work was supported by the
Office of Naval Research Grant N00014-09-1-0582 to
Lamont-Doherty Earth Observatory of Columbia University;
Grants ONR-13759000 and N00014-09-1-0582
to the Woods Hole Oceanographic Institution; Grant
ONR-N00014-06-1-0690 to Scripps Institute of Oceanography;
and a National Defense Science and Engineering
Graduate Fellowship.
Keywords:
Transport
;
Dynamics
;
Topographic effects
;
Currents
;
Empirical orthogonal functions
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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