Dynamic Role of a Westerly Wind Burst in Triggering an Equatorial Pacific Warm Event

Abstract Dynamical impacts of a strong westerly wind burst (WWB) are studied using an ocean–atmosphere coupled simulation in which an intense westerly wind burst is introduced. The ocean response includes local and remote components with the development of a zonal surface jet and the appearance of positive sea surface temperature anomalies in the eastern Pacific. As observed during the triggering of the 1997/98 El Nino, remote warming results from the eastward propagation of a subsurface temperature anomaly generated in the western Pacific. A detailed heat budget helps to describe and understand the major mechanisms taking part to the formation of the subsurface temperature anomaly in the western Pacific, contributing to its eastward propagation and leading to the surface warming simulated in the eastern Pacific. Advective contributions are proved to be widely predominant in the heat budget. Further decomposition of advective terms into linear and nonlinear parts allows insights into the role of mean stat...