Mechanism of the Zonal Displacements of the Pacific Warm Pool: Implications for ENSO
The western equatorial Pacific warm pool is subject to strong east-west migrations on interannual time scales in phase with the Southern Oscillation Index. The dominance of surface zonal advection in this migration is demonstrated with four different current data sets and three ocean models. The eastward advection of warm and less saline water from the western Pacific together with the westward advection of cold and more saline water from the central-eastern Pacific induces a convergence of water masses at the eastern edge of the warm pool and a well-defined salinity front. The location of this convergence is zonally displaced in association with El Nino-La Nina wind-driven surface current variations. These advective processes and water-mass convergences have significant implications for understanding and simulating coupled ocean-atmosphere interactions associated with El Nino-Southern Oscillation (ENSO).
Picaut
J
J. Picaut, M. Ioualalen, T. Delcroix, Groupe SURTROPAC, Institut Francais de Recherche Scientifique pour le Developpement en Cooperation (ORSTOM), BP A5, 98848, Noumea, New Caledonia. C. Menkes, Centre de Recherche Oceanographique, ORSTOM, Abidjan, Ivory Coast. M. J. McPhaden, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA.
Ioualalen
M
Menkes
C
Delcroix
T
McPhaden
MJ