Index Geophysics

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

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.

Yves K. Kouadio

Jacques Servain

Luiz A. T. Machado

Carlos A. D. Lentini

Meteorology. Climatology

QC851-999

Hindawi Limited

2012-01-01T00:00:00Z

article

1687-9309

1687-9317

10.1155/2012/369567

https://doaj.org/article/1beac1d1f989414981a5dcbe80b20153

Advances in Meteorology, Vol 2012 (2012)

EN

http://dx.doi.org/10.1155/2012/369567

https://doaj.org/toc/1687-9309

https://doaj.org/toc/1687-9317

Journal Licence: CC BY