Variations of Sea Surface Fluxes in the Coastal Region

High-rate measurements of turbulence were obtained with the CIRPAS/NPS Twin Otter aircraft in the Monterey Bay, California region throughout the year 2003 in the framework of Autonomous Ocean Sampling Network (AOSN-II) project. Data include about forty flights carried out during midday with a flight pattern consisting of dense near sea surface straight legs and slant soundings north and south of the coverage area. Wind turbulence was estimated from radome data after careful calibration and turbulence quantities like momentum, sensible heat, and latent heat fluxes were calculated. A variety of different patterns of near surface flow patterns were recorded including downcoast and upcoast strong or weak flow as well as offshore flow. Intense topographical effects like flow channeling and thermal flows in combination with stratocumulus cloud and coastal upwelling contribute to the complexity of the wind flow near the coast. In this paper we examine the validity of bulk parameterization schemes like the COARE algorithm for estimation of surface fluxes, which are usually used in atmospheric mesoscale numerical models, in such a complex environment. This is a critical issue in numerical models in order to predict correctly the boundary layer evolution in costal areas. The deviations of the fluxes from bulk parameterization that were found are attributed mainly to the significant non-homogeneity of the flow.