5 YEARS CENTRAL PACIFIC SEA-LEVEL FROM IN-SITU ARRAY, SATELLITE ALTIMETER AND NUMERICAL-MODEL

Temporal and spatial features of central equatorial Pacific Ocean sea- level variation appear similar, in measurements from two very differen t systems (one in the ocean and one carried on a satellite), and in re sults from a numerical model of the region. In particular, there is an interannual cycle: during El Nino, Kelvin waves appear at the equator , and the sea-surface ridge associated with the equatorial current sys tem shifts southward; in non-El Nino years, instability waves appear a t 6-degrees-N (strongest around the end of each calendar year), and th e ridge shifts to the north. This three-way comparison gives support t o both measurement systems and to the numerical model.