32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Wednesday, 6 August 2003: 9:35 AM
Modeling study of the coastal upwelling system of the Monterey Bay area during 1999 and 2000
Igor Shulman, NRL, Bay St. Louis, MS; and J. D. Paduan, L. K. Rosenfeld, S. R. Ramp, and J. C. Kindle
The focus of this paper is to demonstrate the capability of a Monterey Bay area high-resolution model (1-4 km and 30 vertical levels) to track the major features in an upwelling system when constrained by the proposed measurement suite and nested within a regional model. The model was originally configured as part of the Innovative Coastal-Ocean Observing Network (ICON) program. In order to include dominant flow regimes from the California Current system and the important effects of processes crossing from the deep water to the continental shelf, the ICON model is nested within the regional-scale NRL Pacific West Coast (PWC) model. The ICON model has been forced with atmospheric products from both coarser-resolution NOGAPS and finer-resolution COAMPS Navy atmospheric models; the ICON model assimilates HF radar-derived surface currents and MCSST data.

The ICON model simulations reproduce upwelling filaments originating at Pt. Ano Nuevo and Pt. Sur north and south of Monterey Bay, respectively. These upwelling filaments form and decay with realistic space and time scales and produce a realistic meandering front between the cooler, upwelled water and the warmer water of the California Current. A narrow, poleward-flowing California Undercurrent along the continental slope is another realistic feature of the simulations. Analyses of ICON model runs show that high-resolution atmospheric forcing (e.g., COAMPS wind and heat fluxes) as well as accurate open boundary conditions (e.g., PWC model runs also forced with COAMPS) are equally critical for the model accuracy within this relatively small (~100 km) domain. Data assimilation of HF radar-derived surface current maps is shown to improve model tracking of mesoscale features between the surface and depths around 100 m.

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