The vertical structure of the circulation and dynamics in Hudson Shelf Valley

Journal of Geophysical Research
By: , and 

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Abstract

Hudson Shelf Valley is a 20–30 m deep, 5–10 km wide v-shaped submarine valley that extends across the Middle Atlantic Bight continental shelf. The valley provides a conduit for cross-shelf exchange via along-valley currents of 0.5 m s−1 or more. Current profile, pressure, and density observations collected during the winter of 1999–2000 are used to examine the vertical structure and dynamics of the flow. Near-bottom along-valley currents having times scales of a few days are driven by cross-shelf pressure gradients setup by wind stresses, with eastward (westward) winds driving onshore (offshore) flow within the valley. The along-valley momentum balance in the bottom boundary layer is predominantly between the pressure gradient and bottom stress because the valley bathymetry limits current veering. Above the bottom boundary layer, the flow veers toward an along-shelf (cross-valley) orientation and a geostrophic balance with some contribution from the wind stress (surface Ekman layer). The vertical structure and strength of the along-valley current depends on the magnitude and direction of the wind stress. During offshore flows driven by westward winds, the near-bottom stratification within the valley increases resulting in a thinner bottom boundary layer and weaker offshore currents. Conversely, during onshore flows driven by eastward winds the near-bottom stratification decreases resulting in a thicker bottom boundary layer and stronger onshore currents. Consequently, for wind stress magnitudes exceeding 0.1 N m−2, onshore along-valley transport associated with eastward wind stress exceeds the offshore transport associated with westward wind stress of the same magnitude.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The vertical structure of the circulation and dynamics in Hudson Shelf Valley
Series title Journal of Geophysical Research
DOI 10.1002/2014JC009883
Volume 119
Issue 6
Year Published 2014
Language English
Publisher Wiley
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 20 p.
First page 3694
Last page 3713
Country United States
Other Geospatial Hudson Shelf Valley
Online Only (Y/N) N
Additional Online Files (Y/N) N