Tuesday, 11 January 2005: 11:45 AM
Wind stress and wind stress curl during upwelling season along the California coast
Month-long Mesoscale Model 5 (MM5) simulations have been used to investigate the spatial and temporal structure of the marine-layer winds, wind stress, and wind stress curl during upwelling-favorable winds along the California and Baja California coasts. The model results show spatial inhomogeneity of the wind stress and wind stress curl near the coast in response to coastal topographic forcing. Due to the offshore wind maxima near the coast, positive wind stress curl is simulated in a narrow band near the coast, while the region farther offshore is characterized by a broad band of weak and mainly negative wind stress curl. Forcing of the marine flow by the eastward curvature of the coastline generates up-welling positive wind stress curl and consequently the greatest wind stress curl is simulated in the lee of Point Conception and in the Santa Barbara Channel. The model results indicate that the wind stress exhibits great spatial variability in response to synoptic variations, while the wind stress curl has relatively small variation. The study also provides insight into the effect of atmospheric stability on the estimated wind stress and wind stress curl and their effect on ocean dynamics. Differences between the bulk method and methods based on the surface layer similarity theory estimates of the wind stress are elaborated as well as their impact on the wind stress curl computation.