OBSERVED SURFACE OCEANIC AND ATMOSPHERIC VARIABILITY IN THE TROPICAL PACIFIC AT SEASONAL AND ENSO TIMESCALES - A TENTATIVE OVERVIEW

Seasonal and El Nino-Southern Oscillation (ENSO)-related variations of sea surface temperature (SST) and salinity (SSS), 0/450-dbar dynamic height, anomalies (eta, an alias for sea level), zonal (tau(x)) and me ridional(tau(y)) wind stress, wind stress curl (curl (tau)), and preci pitation (P) are examined in the tropical Pacific during 1961-1995. In the equatorial band the El Nino (La Nina) events are chiefly concerne d (1) in the east and center, with warmer (colder) than average SST an d a eta increase (decrease), and (2) in the west, with fresher (saltie r) than average SSS, westerly (easterly) wind anomalies, above (below) average P limited to the east of about 150 degrees E; and a eta decre ase (increase). Much smaller ENSO changes occur away from the equatori al band except in the convergence zones for SSS; P, and tau(y) changes and in two patches centered around 7 degrees N and 7 degrees S in the west for curl (tau). The ENSO-related eta changes are schematically c oncerned with a zonal ''seesaw'' in phase with the Southern Oscillatio n Index (SOI) in the equatorial band and a meridional seesaw between t he regions situated north and south of about 5 degrees N, which lags b y about 1 year behind the SOI. The double seesaws result in a longitud inal mean eta rise (drop) within about 5 degrees N-20 degrees S up to the mature phase of El Nino (La Nina), and not just until its beginnin g, partly compensated by a longitudinal mean eta drop (rise) within ab out 5 degrees-20 degrees N. Aside from its intrinsic substance, this p aper offers a novel and concise observational basis for testing theore tical studies and model simulations.