Effect of Westerly Wind Bursts on a Tropical Ocean General Circulation Model

摘要

A primitive equation general circulation model with imbedded mixed layer physicshas been used to investigate the response of the equatorial Pacific Ocean to daily varying winds and westerly wind bursts. The major issue addressed by this study is the impact of daily varying winds, including westerly wind bursts, in the modeling of the tropical Pacific Ocean and El Nino. In the developmental phase, the sensitivity of the model to the integration time step and the domain size were investigated. The results of this work were used to determine the optimal time step and model domain size for the main experimental model runs. In the experimental phase, the model was spun-up using time averaged wind stresses. The model ocean was then exposed to two years of realistic daily varying wind stresses covering the period of 1991 and 1992. The model developed an El Nino like response that corresponded in several respects with observed features of the 1991-92 El Nino. The model also developed tropical instability waves in the eastern Pacific similar to those observed in situ and in satellite SST images. The model's responses to the tropical cyclones that occurred during 1991-92 were also consistent in several ways with observations. El Nino, Westerly wind burst, OGCM, Mixed layer depth.