Simulation of the sea breeze on the central U.S. California coast

摘要

Land-sea breezes are an important component of coastal atmospheric dynamics and forcing of ocean currents. We have performed a numerical experiment focusing on local circulations including land-sea breezes in the Monterey Bay area located at the central California coast. The dates 22-23 July 1996, characterized by an undisturbed synoptic situation with low and variable winds favorable for development of local circulations, were selected for a case study. A non-hydrostatic version of the MM5 model with a horizontal resolution of 3 km was used to simulate atmospheric dynamics and thermodynamics for the case study. Simulation results showed that the westerly onshore flow was reinforced during the day by the pressure perturbation field over the land. A reversal of the pressure gradient during the night decreased wind speed near the coast, and possibly contributed to offshore components in particular areas of the Bay. Drainage flows from coastal mountains facilitated offshore flows, but these flow patterns were not fully organized and did not generate significantly offshore where synoptic advection dominated. Currently, the model results are being tested by the Naval Postgraduate School in Monterey, CA, as input for an ocean model.