Sea surface height variabilities during 1986--1988 in the tropical Pacific Ocean are described, based upon the Geosat altimeter data and a tropical Pacific Ocean general circulation model (OGCM) simulation forced with observed winds from Florida State University. Both data sets are validated against in situ sea level measurements at 12 selected sea level stations in the equatorial Pacific and were found to be in good agreement with these measurements with correlation coefficients (averaged over the 12 sea level stations in the equatorial Pacific) of 0.69 for Geosat and 0.71 for OGCM. Both the Geosat data and OGCM simulation capture significant amounts of variance of in situ measurements with standard deviations (averaged over the 12 sea level stations) of 7.7 cm for Geosat and 7.1 cm for OGCM as compared with that of 9.8 cm for in situ measurements. The Geosat altimeter data, given their uncertainties, are capable of describing sea surface height variabilities during 1986--1988 in the tropical Pacific Ocean, in particular the seasonal cycle, the 1987 El Ni¿o and 1988 La Ni¿a episodes, and the December 1986 equatorial Kelvin wave event. The OGCM-simulated surface dynamic height is found sensitive to different surface wind products: The standard deviation of the surface dynamic height simulated by the European Center for Medium-Range Weather Forecasting (ECMWF) 10-m wind product is only 5.5 cm. ¿ American Geophysical Union 1993