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Advances in Meteorology
Volume 2012 (2012), Article ID 369567, 16 pages
http://dx.doi.org/10.1155/2012/369567
Research Article

Heavy Rainfall Episodes in the Eastern Northeast Brazil Linked to Large-Scale Ocean-Atmosphere Conditions in the Tropical Atlantic

1Laboratoire de Physique de l’Atmosphère (LPA), UFR-SSMT, Université de Cocody, 22 BP 582, Abidjan 22, Cote D'Ivoire
2Fundação Cearense de Meteorologia e Recursos Hídricos (FUNCEME), Avenida Rui Barbosa 1246, Aldeota, 60115-221 Fortaleza, CE, Brazil
3Institut de Recherche pour le Développement (IRD), UMR182-LOCEAN, Université de Paris VI, 4 Place Jussieu, 75252 Paris, France
4Instituto Nacional de Pesquisas Espaciais (INPE), Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), Rodovia Pres. Dutra, km 40, 12630-000 Cachoeira Paulista, SP, Brazil
5Grupo de Oceanografia Tropical (GOAT), Instituto de Fisica, Departamento de Fisica da Terra e do Meio Ambiente, Universidade Federal da Bahia (UFBA), Travessa Barão de Jeremoabo, s/n, Campus Ondina, 40170-280 Salvador, BA, Brazil

Received 19 December 2011; Accepted 19 May 2012

Academic Editor: Hann-Ming Henry Juang

Copyright © 2012 Yves K. Kouadio et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Relationships between simultaneous occurrences of distinctive atmospheric easterly wave (EW) signatures that cross the south-equatorial Atlantic, intense mesoscale convective systems (lifespan > 2 hour) that propagate westward over the western south-equatorial Atlantic, and subsequent strong rainfall episodes (anomaly > 10 mm·day−1) that occur in eastern Northeast Brazil (ENEB) are investigated. Using a simple diagnostic analysis, twelve cases with EW lifespan ranging between 3 and 8 days and a mean velocity of 8 m·s−1 were selected and documented during each rainy season of 2004, 2005, and 2006. These cases, which represent 50% of the total number of strong rainfall episodes and 60% of the rainfall amount over the ENEB, were concomitant with an acceleration of the trade winds over the south-equatorial Atlantic, an excess of moisture transported westward from Africa to America, and a strengthening of the convective activity in the oceanic region close to Brazil. Most of these episodes occurred during positive sea surface temperature anomaly patterns over the entire south-equatorial Atlantic and low-frequency warm conditions within the oceanic mixing layer. A real-time monitoring and the simulation of this ocean-atmosphere relationship could help in forecasting such dramatic rainfall events.