Investigation of the intra-annual variability of the North Equatorial Counter Current/ North Brazil Current eddies and of the instability waves of the North tropical Atlantic Ocean using satellite altimetry and Empirical Mode Decomposition.

Jean-Luc Mélice (1) , Sabine Arnault (1)

1 VOG - Variabilité de l'Océan et de la Glace de mer

The intra-annual variability of the tropical Atlantic Ocean north of the Equator is investigated with satellite altimetry mean sea level anomalies data, and with an algorithm based on Empirical Mode Decomposition (EMD) methods. Two regions of high variability are identified. The first region, between 3°N-12°N, is characterized by the presence of westward propagating eddies linked to the North Brazil Current (NBC) retroflection in the vicinity of the Brazilian coast. They show a strong annual cycle. Our EMD algorithm points out that this signal is frequency modulated shifting from large lengthscale structures in October to smaller ones in March. Consequently, the number of `eddies'

Mots clés: 4299 General or miscellaneous; OCEANOGRAPHY: GENERAL

Domaines: Géophysique [physics.geo-ph]

Jean-Luc Mélice, Sabine Arnault. Investigation of the intra-annual variability of the North Equatorial Counter Current/ North Brazil Current eddies and of the instability waves of the North tropical Atlantic Ocean using satellite altimetry and Empirical Mode Decomposition.. American Geophysical Union, Fall Meeting 2017, AGU, Dec 2017, New Orleans, United States. ⟨hal-02391870⟩