Aguedjou H. M. A. auteur aut IRD Dadou I. auteur aut IRD Chaigneau Alexis auteur aut IRD Morel Y. auteur aut IRD Alory G. auteur aut IRD text journalArticle eng text/pdf born digital access We study mesoscale eddy characteristics in the tropical Atlantic Ocean, using 23 years of daily altimetry sea level anomalies. Eddies are mainly generated in the eastern boundary upwelling systems and in the Brazil Current region. Their westward propagation speed reaches 20 cm/s in equatorial areas, decreasing with latitudes. They present typical amplitudes of 1-5 cm. The largest and most energetic eddies are observed in the equatorial region, especially in the North Brazil Current (NBC) retroflection. The seasonal cycle of the eddy characteristics shows higher amplitudes along the NBC retroflection and the western part of the North Equatorial Countercurrent. A new criterion, based on altimetry data, determines the probability that barotropic instability of mean surface currents is responsible for eddy generation. We find a strong likelihood that the latter plays a key role along the North Equatorial Countercurrent, whereas other mechanisms must be invoked for the NBC region. specialized mesoscale eddies tropical Atlantic Ocean altimetry seasonal variability barotropic instability ATLANTIQUE ZONE TROPICALE ZONE EQUATORIALE BRESIL 032 126 46 21 12156-12164 2019 0094-8276 https://www.documentation.ird.fr/hor/fdi:010077177 10.1029/2019gl083925 0094-8276 [F B010077177] https://www.documentation.ird.fr/hor/fdi:010077177 https://www.documentation.ird.fr/intranet/publi/depot/2020-11-19/010077177.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2019-12-12 2025-02-24 fdi:010077177 fre