Details:

Journal Title:
Journal of Physical Oceanography
Personal Author:
Conroy, Ted ; Sutherland, David A. ; Ralston, David K.
Conroy, Ted ; Sutherland, David A. ; Ralston, David K. Less -
NOAA Program & Office:
NOS (National Ocean Service) ; OCM (Office for Coastal Management)
NOS (National Ocean Service) ; OCM (Office for Coastal Management) Less -
Description:
Small estuaries in Mediterranean climates display pronounced salinity variability at seasonal and event time scales. Here, we use a hydrodynamic model of the Coos Estuary, Oregon, to examine the seasonal variability of the salinity dynamics and estuarine exchange flow. The exchange flow is primarily driven by tidal processes, varying with the spring–neap cycle rather than discharge or the salinity gradient. The salinity distribution is rarely in equilibrium with discharge conditions because during the wet season the response time scale is longer than discharge events, while during low flow it is longer than the entire dry season. Consequently, the salt field is rarely fully adjusted to the forcing and common power-law relations between the salinity intrusion and discharge do not apply. Further complicating the salinity dynamics is the estuarine geometry that consists of multiple branching channel segments with distinct freshwater sources. These channel segments act as subestuaries that import both higher- and lower-salinity water and export intermediate salinities. Throughout the estuary, tidal dispersion scales with tidal velocity squared, and likely includes jet–sink flow at the mouth, lateral shear dispersion, and tidal trapping in branching channel segments inside the estuary. While the estuarine inflow is strongly correlated with tidal amplitude, the outflow, stratification, and total mixing in the estuary are dependent on the seasonal variation in river discharge, which is similar to estuaries that are dominated by subtidal exchange flow.
Keywords:
[+]
Estuaries
Hydrodynamics
Oceanography

Source:
Journal of Physical Oceanography, 50(3), 595-613
DOI:
https://doi.org/10.1175/JPO-D-19-0108.1
Document Type:
Journal Article
Funding:
Grant no. NA14NOS4190145
Place as Subject:
Coos Bay Estuary (Or.)
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:fac3a8846412e84c1815069bc61dde0920b1309caa830928b9321924412dccc2
File Type:

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