Monday, 23 January 2012: 4:00 PM
Coastal Southern California Sea Surface Winds and Along Coast Pressure Gradient Related to Mid-Level Atmospheric Structure
Room 338 (New Orleans Convention Center )
During summer along the central California coast and around Point Conception California, the winds are dominantly along-coast and equatorward (upwelling favorable). Sea surface buoy-measured winds are strongly correlated with the along-coast pressure gradient and mid-level atmospheric structure. Sea surface buoy measured wind speeds stronger than 7 m/s are driven by an along-coast pressure gradient of greater than 0.8 hPa/100 km, and are concurrent with a 500 hPa mid-level trough axis to northwest. During the passage of the 500 hPa trough over Point Conception, the upwelling-favorable wind pattern can be altered and the sea surface, coastal winds relax or reverse and blow northward. Wind reversals initiate with wind shifts in the Southern California Bight, then progress northward around Point Conception. The North American Regional Reanalysis (NARR) atmospheric operational model does well in simulating the episodes of weakened along-coast pressure gradient, the areas of higher and weakened wind speeds and the wind direction reversals.