3.2
(Invited Talk) The cause of the over water, summer wind speed maximum about the Pt Conception Sharp Coastal Bend
Clive E. Dorman, SIO/Univ. Of California, La Jolla, CA; and D. Koracin
Pt Conception, California is a part of a large topographic complex that extends offshore, forming the most extreme bend along the US West Coast. A summer wind speed maximum extending more than 200 km away occurs overwater around Pt Conception California. The causes for this wind speed maximum include several major determinants that were investigated using surface stations, profilers and mesoscale model simulations. Synoptic conditions are dominant, setting the general wind speed around the Point. Frequently occurring is a strong wind maximum that extends about the Pt Conception including well offshore toward the SW and with the highest speeds with in 20km to the south. Less frequently occurring are moderate wind cases that do not extend as far offshore and have a moderate maximum wind speed that occurs over a smaller area in the western mouth of the Santa Barbara Channel. Within the synoptic scale context, next most important is hydraulic expansion fan dynamics that significantly increase the wind speeds over a large area extending to the SW, S and E of Point Conception, as well as the maximum wind speed, for the strong and moderate synoptic cases. Thermally driven flow due to differential heating over land in the greater Los Angles coastal and elevated area to the east is not directly related to the wind speed maximum either in the Santa Barbara Channel nor in the open ocean extending farther offshore. Downslope flow on the south side of the Santa Ynez Mountains generated by cross Santa Ynez mountain ridge winds does not contribute to the high speed wind maximum in the Santa Barabra channel and not to that extending farther offshore. A major effect of the Santa Barbara Channel Islands is to extend the zone of high speed winds farther to the south than would otherwise be the case. .
Session 3, Advancing our modeling capabilities/tools: US West Coast
Tuesday, 11 September 2007, 2:15 PM-5:00 PM, Boardroom
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