Horizon 1 1 10 C-ACTI : Communications avec actes dans un congrès international Western Pacific international meeting and workshop on Toga Coare : proceedings Western Pacific International Meeting and Workshop on Toga Coare 259-268 NIVEAU MARIN ANOMALIE EL NINO ONDE ROSSBY 1986 1987 PACIFIQUE EQUATORIAL OUEST 1989 1989/05/24-30 Nouméa ORSTOM fdi:30213 ENG https://www.documentation.ird.fr/hor/fdi:30213 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/doc34-08/30213.pdf Horizon (IRD) Thanks to the GEOSAT altimeter data set, information on sea level changes during the 1986-87 El Nino is presented. Special emphasis is placed on the warm pool area, with an evaluation, a detailed description and tentative explanation of the observed Sea Level Anomaly (SLA) changes. Near the 165°E longitude,the onset of the 1986-87 El Nino is characterized by a rapid development of a positive (> 14 cm) equatorial SLA in november-december 1986. This feature occurs in response to an eastward wind anomaly appearing between 140°E-170°W along the equator. The wind induces a downwelling equatorial Kelvin wave with phase speed of about 2.3 m.s.-1. Thereafter, equatorial SLA remains quite constant from january to april/may 1987. In june 1987, equatorial SLA decreases to a minimum value, just after an abrupt change of the zonal wind stress anomaly, west of 165°E. Such anomaly seems to force an upwelling equatorial Kelvin wave propagating at about 2.3. m.s-1. 032DYNEAU