Ocean Circulation Modeling in Support of ECOHAB PNW

Michael Foreman¹, Emanuele Di Lorenzo², Barbara Hickey³, and Amy MacFadyen⁴

¹ Institute of Ocean Sciences, Sidney B.C., V8L 4B2, Canada. E-mail: foremanm@dfo-mpo.gc.ca
²Scripps Institution of Oceanography, La Jolla, 92093-0224, USA. Email: edl@ucsd.edu
³School of Oceanography, University of Washington, Seattle, 98195-07940, USA. Email: bhickey@u.washington.edu
⁴School of Oceanography, University of Washington, Seattle, 98195-07940, USA. Email: amoreena@ocean.washington.edu

Recent studies suggest that the Juan de Fuca Eddy, a seasonal nutrient-rich retentive feature off the Washington and British Columbia coasts, may be an initiation site for the toxigenic phytoplankton Pseudo-nitzschia that impact shellfish along the Washington coast. As part of ECOHAB PNW, a project funded by the Ecology and Oceanography of Harmful Algal Blooms program, two ocean circulation models, ROMS and ELCIRC, have been used i) to conduct process studies into the mechanisms underlying the generation and collapse of the eddy and, ii) to simulate the ocean circulation during a three-week cruise in June 2003. During this cruise, two periods of upwelling winds which supported the eddy were separated by a downwelling storm which caused the eddy to collapse. In this presentation, we will discuss the eddy generation dynamics and demonstrate via comparisons with ship-board ADCP and mooring observations that the model has successfully reproduced the June 2003 ocean circulation.