The 1996 Equatorial Atlantic warm event: origin and mechanisms

Serena Illig (1) , Daria Gushchina (2) , Boris Dewitte (1) , Nadia Ayoub (1) , Yves Du Penhoat (1)

1 ECOLA - Echanges Côte-Large
2 Geographical Faculty

We investigate the interannual warm event that occurred in the equatorial Atlantic in boreal spring-summer 1996. The role of local coupled air-sea interactions versus Tropical Pacific remote forcing is analysed using observations and ensemble experiments of an intermediate coupled model of the Tropical Atlantic. Results show that the persistent anomalous cold conditions in the Tropical Pacific over 1995-96 were favorable to the growth of the local air-sea interactions that led to the 1996 warming in the equatorial Atlantic. Based on the estimation of the changes in the Walker circulation over the Pacific and Atlantic for the meteorological reanalyses and the coupled model, a mechanism of Pacific-Atlantic equatorial connection is proposed to explain this particular warm episode.

Mots clés: Atlantic Ocean; Climate and interannual variability; Equatorial oceanography; Numerical modeling; Ocean/atmosphere interactions

Domaines: Planète et Univers [physics]

Serena Illig, Daria Gushchina, Boris Dewitte, Nadia Ayoub, Yves Du Penhoat. The 1996 Equatorial Atlantic warm event: origin and mechanisms. Geophysical Research Letters, 2006, 33 (9), pp.L09701. ⟨10.1029/2005GL025632⟩. ⟨hal-00280344⟩