Residual Circulation in Shallow Estuaries 2. Weakly Stratified and Partially Mixed, Narrow Estuaries

Authors

David A. Jay, Portland State UniversityFollow
J. Dungan Smith, University of Washington - Seattle CampusFollow

Document Type

Article

Publication Date

1-1-1990

Subjects

Oceanic mixing, Estuaries -- Turbulence, Tides -- Columbia River Estuary (Or. and Wash.) -- Mathematical models, Internal waves

Abstract

Long-wave theory is used herein to analyze circulation in weakly stratified and partially mixed estuaries. Unlike the highly stratified systems considered in part 1, the flows considered here have only a minimal tidal-frequency internal wave component. These estuaries may therefore be modeled as the sum of weakly interacting barotropic and baroclinic modes. The dominant factors driving the residual flow are finite amplitude barotropic effects in weakly stratified estuaries and a combination of barotropic effects and steady horizontal density gradient forcing in partially mixed estuaries. The dominant vertical exchange mechanism in the weakly stratified case is bottom boundary-induced turbulence, and that in partially mixed estuaries is believed to be random internal wave interactions. A model of the Columbia River Estuary under weakly stratified conditions accurately predicts the observed residual velocity and salinity fields, and the tidal amplitude at which a transition to a highly stratified state takes place. The partially mixed state is unstable in the Columbia River Estuary because the tides and buoyancy input are both too strong.

Description

Copyright 1990 American Geophysical Union

*At the time of publication David A. Jay was affiliated with the University of Washington

Persistent Identifier

http://archives.pdx.edu/ds/psu/8071

Citation Details

Jay, D. A., and J. D. Smith (1990), Residual Circulation in Shallow Estuaries 2. Weakly Stratified and Partially Mixed, Narrow Estuaries, J. Geophys. Res., 95(C1), 733–748.