Micrometeorological Characteristics of the Sea Breeze During the Wilmington 2005 Urban Dispersion Study

The urban dispersion study took place in Wilmington, California, in June 2005, with the main goal to facilitate evaluation and improvement of a newly developed urban dispersion model for the California Air Resources Board. The meteorological equipment consisting of mini-sodars, sonic anemometers, a hygrometer, a microwave temperature profiler and energy balance instruments was deployed at the release site and another site located four kilometers inland. This instrumentation setup enabled investigations of the micrometeorological characteristics related to the interactions between the marine and urban boundary layers. The days with offshore synoptic winds were taken into the consideration when the distinct sea breeze pattern can be discerned from the ambient flows. The sea breeze layer depth and the convective internal boundary layer depth were determined from the remote sensing measurements and compared to the theoretical models. The micrometeorological characteristics of the sea breeze front in the surface layer were analyzed from the mean wind and turbulence properties. The contributions to the turbulence energy dissipation from the mechanical and thermal effects were discussed.