Ekman transport and pumping in the California Current based on the U.S. Navy's high-resolution atmospheric model (COAMPS)

[1] Upwelling in the California Current system due to Ekman transport and pumping was estimated using a high-resolution ( 9-km grid) atmospheric model reanalysis. Model winds, verified with satellite-measured winds at 13 locations, had weekly averaged wind components within 1.7 m s(-1) RMS, and wind gradients within 1.6 m s(-1) per 100 km RMS. Model wind hind-casts from May 1999 to September 2000 revealed narrow bands ( about 10 by 50 km) of strong wind stress and wind stress curl parallel to the coast and adjacent to major coastal promontories. These bands, which are sub-grid scale in operational models, were capable of generating local upwelling greater than 10 m d(-1) and downwelling greater than 5 m d(-1). Peak summer estimates for the California Current system indicate vertical transport due to Ekman pumping was roughly 1.0 x 10(-6) m(3) s(-1), and Ekman transport from alongshore wind stress was about 0.5 x 10(-6) m(3) s(-1). These estimates suggest that Ekman pumping from wind stress curl is as important as Ekman transport from alongshore winds in the California Current system.