The Columbia river plume as cross-shelf exporter and along-coast barrier

N. S. Banas, P. MacCready, B. M. Hickey

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

An intensive Lagrangian particle-tracking analysis of the July 2004 upwelling period was conducted in a hindcast model of the US Pacific Northwest coast, in order to determine the effect of the Columbia River plume on the fate of upwelled water. The model, implemented using Regional Ocean Modeling System (ROMS), includes variable wind and atmospheric forcing, variable Columbia river flow, realistic boundary conditions from Navy Coastal Ocean Model (NCOM), and 10 tidal constituents. Model skill has been demonstrated in detail elsewhere [MacCready, P., Banas, N.S., Hickey, B.M., Dever, E.P., Liu, Y., 2008. A model study of tide- and wind-induced mixing in the Columbia River estuary and plume. Continental Shelf Research, this issue, doi:10.1016/j.csr.2008.03.015]. Particles were released in the Columbia estuary, along the Washington coastal wall, and along the model's northern boundary at 48°N. Particles were tracked in three dimensions, using both velocities from ROMS and a vertical random displacement representing turbulent mixing. When 25 h of upwelling flow is looped and particles tracked for 12 d, their trajectories highlight a field of transient eddies and recirculations on scales from 5 to 50 km both north and south of the Columbia. Not all of these features are caused by plume dynamics, but the presence of the plume increases the entrainment of inner-shelf water into them. The cumulative effect of the plume's interaction with these transient features is to increase cross-shelf dispersion: 25% more water is transported laterally past the 100 m isobath when river and estuarine effects are included than when they are omitted. This cross-shelf dispersion also disrupts the southward transport of water along the inner shelf that occurs in the model when the Columbia River is omitted. This second effect-increased retention of upwelled water on the Washington shelf-may be partly responsible for the regional-scale alongcoast gradient in chlorophyll biomass, although variations in shelf width, the Juan de Fuca Eddy to the north, and the intermittency of upwelling-favorable winds are likely also to play important roles.

LanguageEnglish
Pages292-301
Number of pages10
JournalContinental Shelf Research
Volume29
Issue number1
DOIs
Publication statusPublished - 15 Jan 2009

Fingerprint

river plume
Columbia River
coasts
coast
plume
upwelling
oceans
eddy
ocean
water
estuary
river
tidal constituent
estuaries
atmospheric forcing
turbulent mixing
wind forcing
river flow
entrainment
modeling

Keywords

  • California current system
  • coastal upwelling
  • Columbia river
  • lagrangian methods
  • numerical modeling
  • Pacific northwest
  • river plumes

Cite this

Banas, N. S. ; MacCready, P. ; Hickey, B. M. / The Columbia river plume as cross-shelf exporter and along-coast barrier. In: Continental Shelf Research. 2009 ; Vol. 29, No. 1. pp. 292-301.
@article{373d4899f06c46d0b68645cc4fa1c6c9,
title = "The Columbia river plume as cross-shelf exporter and along-coast barrier",
abstract = "An intensive Lagrangian particle-tracking analysis of the July 2004 upwelling period was conducted in a hindcast model of the US Pacific Northwest coast, in order to determine the effect of the Columbia River plume on the fate of upwelled water. The model, implemented using Regional Ocean Modeling System (ROMS), includes variable wind and atmospheric forcing, variable Columbia river flow, realistic boundary conditions from Navy Coastal Ocean Model (NCOM), and 10 tidal constituents. Model skill has been demonstrated in detail elsewhere [MacCready, P., Banas, N.S., Hickey, B.M., Dever, E.P., Liu, Y., 2008. A model study of tide- and wind-induced mixing in the Columbia River estuary and plume. Continental Shelf Research, this issue, doi:10.1016/j.csr.2008.03.015]. Particles were released in the Columbia estuary, along the Washington coastal wall, and along the model's northern boundary at 48°N. Particles were tracked in three dimensions, using both velocities from ROMS and a vertical random displacement representing turbulent mixing. When 25 h of upwelling flow is looped and particles tracked for 12 d, their trajectories highlight a field of transient eddies and recirculations on scales from 5 to 50 km both north and south of the Columbia. Not all of these features are caused by plume dynamics, but the presence of the plume increases the entrainment of inner-shelf water into them. The cumulative effect of the plume's interaction with these transient features is to increase cross-shelf dispersion: 25{\%} more water is transported laterally past the 100 m isobath when river and estuarine effects are included than when they are omitted. This cross-shelf dispersion also disrupts the southward transport of water along the inner shelf that occurs in the model when the Columbia River is omitted. This second effect-increased retention of upwelled water on the Washington shelf-may be partly responsible for the regional-scale alongcoast gradient in chlorophyll biomass, although variations in shelf width, the Juan de Fuca Eddy to the north, and the intermittency of upwelling-favorable winds are likely also to play important roles.",
keywords = "California current system, coastal upwelling, Columbia river, lagrangian methods, numerical modeling, Pacific northwest, river plumes",
author = "Banas, {N. S.} and P. MacCready and Hickey, {B. M.}",
year = "2009",
month = "1",
day = "15",
doi = "10.1016/j.csr.2008.03.011",
language = "English",
volume = "29",
pages = "292--301",
journal = "Continental Shelf Research",
issn = "0278-4343",
number = "1",

}

The Columbia river plume as cross-shelf exporter and along-coast barrier. / Banas, N. S.; MacCready, P.; Hickey, B. M.

In: Continental Shelf Research, Vol. 29, No. 1, 15.01.2009, p. 292-301.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The Columbia river plume as cross-shelf exporter and along-coast barrier

AU - Banas, N. S.

AU - MacCready, P.

AU - Hickey, B. M.

PY - 2009/1/15

Y1 - 2009/1/15

N2 - An intensive Lagrangian particle-tracking analysis of the July 2004 upwelling period was conducted in a hindcast model of the US Pacific Northwest coast, in order to determine the effect of the Columbia River plume on the fate of upwelled water. The model, implemented using Regional Ocean Modeling System (ROMS), includes variable wind and atmospheric forcing, variable Columbia river flow, realistic boundary conditions from Navy Coastal Ocean Model (NCOM), and 10 tidal constituents. Model skill has been demonstrated in detail elsewhere [MacCready, P., Banas, N.S., Hickey, B.M., Dever, E.P., Liu, Y., 2008. A model study of tide- and wind-induced mixing in the Columbia River estuary and plume. Continental Shelf Research, this issue, doi:10.1016/j.csr.2008.03.015]. Particles were released in the Columbia estuary, along the Washington coastal wall, and along the model's northern boundary at 48°N. Particles were tracked in three dimensions, using both velocities from ROMS and a vertical random displacement representing turbulent mixing. When 25 h of upwelling flow is looped and particles tracked for 12 d, their trajectories highlight a field of transient eddies and recirculations on scales from 5 to 50 km both north and south of the Columbia. Not all of these features are caused by plume dynamics, but the presence of the plume increases the entrainment of inner-shelf water into them. The cumulative effect of the plume's interaction with these transient features is to increase cross-shelf dispersion: 25% more water is transported laterally past the 100 m isobath when river and estuarine effects are included than when they are omitted. This cross-shelf dispersion also disrupts the southward transport of water along the inner shelf that occurs in the model when the Columbia River is omitted. This second effect-increased retention of upwelled water on the Washington shelf-may be partly responsible for the regional-scale alongcoast gradient in chlorophyll biomass, although variations in shelf width, the Juan de Fuca Eddy to the north, and the intermittency of upwelling-favorable winds are likely also to play important roles.

AB - An intensive Lagrangian particle-tracking analysis of the July 2004 upwelling period was conducted in a hindcast model of the US Pacific Northwest coast, in order to determine the effect of the Columbia River plume on the fate of upwelled water. The model, implemented using Regional Ocean Modeling System (ROMS), includes variable wind and atmospheric forcing, variable Columbia river flow, realistic boundary conditions from Navy Coastal Ocean Model (NCOM), and 10 tidal constituents. Model skill has been demonstrated in detail elsewhere [MacCready, P., Banas, N.S., Hickey, B.M., Dever, E.P., Liu, Y., 2008. A model study of tide- and wind-induced mixing in the Columbia River estuary and plume. Continental Shelf Research, this issue, doi:10.1016/j.csr.2008.03.015]. Particles were released in the Columbia estuary, along the Washington coastal wall, and along the model's northern boundary at 48°N. Particles were tracked in three dimensions, using both velocities from ROMS and a vertical random displacement representing turbulent mixing. When 25 h of upwelling flow is looped and particles tracked for 12 d, their trajectories highlight a field of transient eddies and recirculations on scales from 5 to 50 km both north and south of the Columbia. Not all of these features are caused by plume dynamics, but the presence of the plume increases the entrainment of inner-shelf water into them. The cumulative effect of the plume's interaction with these transient features is to increase cross-shelf dispersion: 25% more water is transported laterally past the 100 m isobath when river and estuarine effects are included than when they are omitted. This cross-shelf dispersion also disrupts the southward transport of water along the inner shelf that occurs in the model when the Columbia River is omitted. This second effect-increased retention of upwelled water on the Washington shelf-may be partly responsible for the regional-scale alongcoast gradient in chlorophyll biomass, although variations in shelf width, the Juan de Fuca Eddy to the north, and the intermittency of upwelling-favorable winds are likely also to play important roles.

KW - California current system

KW - coastal upwelling

KW - Columbia river

KW - lagrangian methods

KW - numerical modeling

KW - Pacific northwest

KW - river plumes

UR - http://www.scopus.com/inward/record.url?scp=57749106882&partnerID=8YFLogxK

UR - http://www.sciencedirect.com/science/article/pii/S0278434308001052

U2 - 10.1016/j.csr.2008.03.011

DO - 10.1016/j.csr.2008.03.011

M3 - Article

VL - 29

SP - 292

EP - 301

JO - Continental Shelf Research

T2 - Continental Shelf Research

JF - Continental Shelf Research

SN - 0278-4343

IS - 1

ER -