TY - JOUR
T1 - Observations at the tidal plume front of a high-volume river outflow
AU - Orton, Philip M.
AU - Jay, David A.
PY - 2005/6/16
Y1 - 2005/6/16
N2 - We present shipboard observations of very strong convergence, vertical velocities and mixing, and nearbed impacts associated with the leading-edge front of the tidally-pulsed Columbia River plume. With upwelling-favorable winds and riverflow of 4900 m3s-1, the plume propagates as a buoyant gravity current with a rotary, borelike vertical frontal circulation and downwelling as strong as 0.35 m s-1. In waters as deep as 65 m, near-bed currents intensify to as much as 1.0 m s-1 after frontal passage, and are often associated with elevated acoustic backscatter. Mixing is locally strong, with an eddy diffusivity of O(0.2 m2s-1) 50 m behind the front, and T-S diagrams imply plume mixing with 10 m deep ocean water. These observations indicate that the leading-edge front of a surface-advected plume can cause exchanges of (a) nutrients between cold subsurface shelf waters and the river plume, and (b) nutrients and sediments across the sediment-water interface.
AB - We present shipboard observations of very strong convergence, vertical velocities and mixing, and nearbed impacts associated with the leading-edge front of the tidally-pulsed Columbia River plume. With upwelling-favorable winds and riverflow of 4900 m3s-1, the plume propagates as a buoyant gravity current with a rotary, borelike vertical frontal circulation and downwelling as strong as 0.35 m s-1. In waters as deep as 65 m, near-bed currents intensify to as much as 1.0 m s-1 after frontal passage, and are often associated with elevated acoustic backscatter. Mixing is locally strong, with an eddy diffusivity of O(0.2 m2s-1) 50 m behind the front, and T-S diagrams imply plume mixing with 10 m deep ocean water. These observations indicate that the leading-edge front of a surface-advected plume can cause exchanges of (a) nutrients between cold subsurface shelf waters and the river plume, and (b) nutrients and sediments across the sediment-water interface.
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U2 - 10.1029/2005GL022372
DO - 10.1029/2005GL022372
M3 - Article
AN - SCOPUS:23844435603
SN - 0094-8276
VL - 32
SP - 1
EP - 4
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 11
ER -