A census of Tehuantepec and Papagayo eddies in the northeastern tropical Pacific

Abstract

We use a 12-year (1992-2004) time series of satellite altimetry to characterize long-lived, wind-generated anticyclonic eddies originating in the Gulfs of Tehuantepec and Papagayo in the northeastern tropical Pacific. A total of 42 Tehuantepec and 26 Papagayo eddies were observed. Eddy merging, usually of a Tehuantepec-Papagayo pair, was observed on 16 occasions. On average, the eddy season began in late October and lasted approximately 250 days until early July, with 3.5 Tehuantepec and 2.2 Papagayo eddies formed each year. Minimum average eddy lifespan was 143 days and 84 days for Tehuantepec and Papagayo eddies, respectively. There was considerable interannual variability in eddy activity, with greater (fewer) number of eddies, more intense (weaker) eddies, and a longer (shorter) eddy season during El Niñio (La Niña) years. Eddy intensification was consistently observed at the East Pacific Rise.