A Diagnostic Study of the Velocity Structure of a Meandering Jet in the California Current System Using a Primitive Equation Model
Abstract
A high resolution 20-level, primitive equation model is initialized using sigma-theta data acquired during a Coastal Transition Zone (CTZ) cruise from 6 to 12 July 1988 near Point Arena, California for the purpose of diagnosing the three-dimensional dynamically balanced flow field for the region. The major feature in the region during the cruise period was a strong meandering jet which flowed equatorward and offshore, oriented in a northeast to southwest direction. A density diagnostic version of the model, in which the sigma-theta is held constant during the 72 hour integration time, is compared with a robust diagnostic version of the model, in which the sigma-theta field is allowed to adjust dynamically within the constraints of a damping time scale. The density diagnostic version of the model produces vertical velocities which are an order of magnitude larger than vertical calculated from bio-optical data collected in the same location and at the same time as the CTZ cruise. The robust diagnostic version produced vertical velocities within the range of vertical velocities calculated from the bio-optical data. The horizontal pattern of vertical velocity from the robust diagnostic version also compared well with patterns seen in trough/ridge systems in the Gulf Stream. In particular, there is horizontal convergence and downwelling all along the offshore directed part of the meandering jet. Vertical cross-section comparisons between model velocity data and ADCP velocity data collected during the cruise revealed differences which may be caused by factors neglected by the model (e.g. bottom topography, wind forcing, and heat fluxes).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1991
- Accession Number
- ADA246039
Entities
People
- James R. Mallette Jr.
Organizations
- Naval Postgraduate School