HR: 1340h
AN: OS13A-0513    [Abstracts]
TI: Surface Drifter Behavior off of the Columbia River - July 2004
AU: * McCabe, R M
EM: rmccabe@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 355351, Seattle, WA 98195 United States
AU: Hickey, B M
EM: bhickey@u.washington.edu
AF: University of Washington, School of Oceanography Box 355351, Seattle, WA 98195 United States
AU: MacCready, P
EM: parker@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 355351, Seattle, WA 98195 United States
AB: Surface GPS-drifters were released offshore of the Columbia River in July 2004 as part of the first RISE (River Influences on Shelf Ecosystems) cruise. The deployments were made in order to track surface currents and Columbia River plume water near the river mouth and over the shelf. Nineteen deployments ranging from 1 to 45 days in length were completed over 10 different days. Along-track measurements of temperature were recorded by each drifter. Roughly half of the drifters deployed also measured conductivity. Drifter behavior proved to be highly dependent on both wind stress and tidal phase. Drifters deployed in the river mouth near the time of maximum ebb were exported $\sim$27 km offshore to the head of Astoria Canyon in only six hours. One drifter was also deployed off the river mouth during a period of strong downwelling-favorable winds. This drifter circulated anti-cyclonically and moved onshore in a retentive feature north of the mouth. Drifters released off the river mouth near the start of ebb were initially transported southwestward. These drifters then circulated shoreward in a cyclonic eddy-like feature south of the river mouth as the winds changed to favor downwelling. Half of the deployments ended with drifters washing ashore. Overall, the drifter tracks illustrate an enhanced dispersion of plume waters over the Oregon and Washington shelves by both the winds and tidal outflow.
UR: http://www.ocean.washington.edu/rise/index.htm
DE: 4219 Continental shelf processes
DE: 4279 Upwelling and convergences
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting