HR: 12:05h
AN: OS32B-08    [Abstracts]
TI: Wind-driven coastal circulation response to the presence of a shallow submarine bank
AU: * Castelao, R M
EM: castelao@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, 104 COAS Administration Building, Corvallis, OR 97331-5503 United States
AU: Barth, J A
EM: barth@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, 104 COAS Administration Building, Corvallis, OR 97331-5503 United States
AB: The coastal upwelling region off Oregon is studied using both observations and numerical modeling. Repeated mesoscale surveys of waters over the shelf and slope were conducted during spring and summer of 2001 to study the spatial structure of the velocity and hydrographic fields. The results show that the presence of a shallow submarine bank (Heceta Bank) increases the cross-isobath transport, as the coastal upwelling jet is driven offshore leading to separation. The wind stress plays an important role in the separation, as it speeds up the currents making the jet more inertial. Comparisons between the wind stress and the position of the upwelling front derived from satellite images support that idea. Bank geometry and stratification are also important in the jet separation process. A three-dimensional numerical model (POM) is used to explore the relative importance of these parameters. Preliminary results using idealized bank topography suggest that both the Rossby number and the Burger number (formed using the radius of curvature of the topography as the length scale) are important. For strong wind conditions, maximum separation occurs for Burger numbers between 0.3 and 0.7. An increase in the Rossby number also leads to more separation. Future simulations will explore variations in other parameters/geometries, including the use of realistic bottom topography for Oregon's shelf and slope.
DE: 4219 Continental shelf processes
DE: 4279 Upwelling and convergences
DE: 4528 Fronts and jets
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting