Extended Abstract (460K)5.9
Simulation of Interaction of the Atmospheric Marine Layer with Point Conception
Clive E. Dorman, SIO/Univ. of California, La Jolla, CA; and D. R. Koracin
Point Conception is the most pronounced eastward turn of the California coast. An unusually dense network of surface meteorological stations is available on the upwind and downwind coasts that characterize the horizontal wind structure about this Point. During the summer, the inbound marine layer flow is aligned at 310 degrees N with the linear Central California Coast so that the flow approaches the N-S coast of Point Conception at an angle of 50 degrees. Mesoscale Model 5 (MM5) has been used to simulate the flow around Point Conception for all of June 1996. The model evaluation shows that MM5 simulates the marine layer conditions very well in comparisons with over water and a near over water measurements using more than 15 buoys, platforms and Island stations. The model simulations show that the inbound marine layer adjusts to the western presence of the point complex in less than 15 km, slowing and over running the lower areas, continuing up the E-W extending valleys or turning southward to go around. The marine layer is thickest on the upwind side, being deepest at sunrise and shallowest in the afternoon. A portion of the marine layer turns around Point Conception to become parallel with the E-W oriented lee coast, while thinning and accelerating. Wind speed maximum and marine layer depth minimum are in the western mouth of the Santa Barbara Channel. As a result, a compression bulge forms on the upwind side of Point Conception where the wind speed decreases and the marine layer thickens. The lee is a transcritical expansion fan where the winds accelerate and the marine layer thins.
Session 5, atmospheric and oceanic processes
Thursday, 13 January 2005, 8:30 AM-11:45 AM
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