Secondary currents in a curved, stratified, estuarine channel

Journal of Geophysical Research C: Oceans
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Abstract

This paper presents a study of secondary circulation in a curved stratified channel in northern San Francisco Bay over a 12.5-hour tidal cycle. Secondary currents were strong at times (varying by up to 35 cm/s from top to bottom) but relatively transient, as the balance between centrifugal and lateral baroclinic forcing changed over time. The short travel time around the bend did not allow a steady state balance to develop between centrifugal and lateral baroclinic forcing. During the flood tide the confluence of two streams with different velocities produced a strong lateral gradient in streamwise velocity. As a result, lateral advection was a significant term in the streamwise momentum balance, having the same order of magnitude as the barotropic and baroclinic pressure gradients, and the frictional terms. During the first part of the ebb, secondary currents were induced by lateral baroclinic forcing. The direction of the secondary circulation reversed later in the ebb, as the baroclinic forcing became weaker than the centrifugal acceleration. The gradient Richardson number showed that stratification was stable over most of the tidal cycle, decreasing the importance of friction and allowing secondary currents to persist.

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Publication type Article
Publication Subtype Journal Article
Title Secondary currents in a curved, stratified, estuarine channel
Series title Journal of Geophysical Research C: Oceans
DOI 10.1029/2000JC000606
Volume 106
Issue C12
Year Published 2001
Language English
Publisher American Geophysical Union
Description 20 p.
First page 31283
Last page 31302
Country United States
State California
City San Francisco
Other Geospatial San Francisco Bay
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