Layered mixing on the New England Shelf in summer
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Authors
Wang, Jianing
Greenan, Blair J.W.
Lu, Youyu
Oakey, Neil S.
Shaw, William J.
Subjects
Advisors
Date of Issue
2014
Date
Publisher
Language
Abstract
The layered structure of stratification and mixing on the New England Shelf (NES) in summer is
examined by analyzing a comprehensive set of observations of hydrography, currents and turbulence. A
clear distinction in mixing characteristics between the midcolumn water (consisting of subsurface stratification,
middepth weak stratification and lower-layer stratification) and a well-mixed bottom boundary layer
(BBL) is revealed. The combination of subtidal Ekman onshore bottom transport and cross-shore density
gradient created a lower-layer stratification that inhibited the upward extension of the BBL turbulence. The
BBL mixing was related to strong shear generated by bottom stress, and the magnitude and periodic variation
of BBL mixing was determined by both the tidal and subtidal flows. Mixing in the midcolumn water
occurred under stably stratified conditions and showed correspondence with the occurrence of near-inertial
and semidiurnal internal waves. Positive correlations between buoyancy frequency squared (N2) and shear
variance (S2), S2 and dissipation rate (e), N2 and e are established in the midcolumn, but not in the BBL. The
midcolumn e was reasonably described by a slightly modified MacKinnon-Gregg (MG) model.
Type
Article
Description
The article of record as published may be located at http://dx.doi.org/10.1002/2014JC009947
Series/Report No
Department
Oceanography
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NPS Report Number
Sponsors
The field component of this program was jointly supported by the US Office of Naval Research (grants N00014-95-1-1030, N00014-95-1-0373, and N00014-96-1- 0953) and Fisheries and Oceans of Canada.
Funder
Format
Citation
Wang, J., B. J. W. Greenan, Y. Lu, N. S.
Oakey, and W. J. Shaw (2014), Layered
mixing on the New England Shelf in
summer, J. Geophys. Res. Oceans, 119,
5776–5796, doi:10.1002/
2014JC009947.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.