SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil

Type Article
Date 2019-06
Language English
Author(s) Hounsou-Gbo Gbekpo Aubains1, 2, 3, Servain Jacques1, 4, Araujo MoacyrORCID3, 5, Caniaux Guy6, Bourles Bernard2, 7, Fontenele DiogenesORCID1, Martins Eduardo Savio P. R.1
Affiliation(s) 1 : Res Inst Meteorol & Water Resources FUNCEME, Ave Rui Barbosa 1246, BR-60115221 Fortaleza, CE, Brazil.
2 : UAC, ICMPA, Unesco Chair, 072 POB 50, Cotonou, Benin.
3 : Brazilian Res Network Global Climate Change Rede, Ave Astronautas 1758, BR-12227010 Sao Jose Dos Campos, SP, Brazil.
4 : IRD, LOCEAN, F-75005 Paris, France.
5 : Fed Univ Pernambuco UFPE, LOFEC, Dept Oceanog, DOCEAN, Ave Arquitetura S-N, BR-50740550 Recife, PE, Brazil.
6 : Meteo France CNRS, CNRM UMR 3589, 42 Ave G Coriolis, F-31057 Toulouse 01, France.
7 : IRD, IMAGO, F-29280 Plouzane, France.
Source Atmosphere (2073-4433) (Mdpi), 2019-06 , Vol. 10 , N. 6 , P. 335 (21p.)
DOI 10.3390/atmos10060335
WOS© Times Cited 3
Note This article belongs to the Special Issue Tropical Atlantic Variability
Keyword(s) Brazilian Northeast, rainfall, predictability, tropical Atlantic
Abstract

May-to-July and February-to-April represent peak rainy seasons in two sub-regions of Northeast Brazil (NEB): Eastern NEB and Northern NEB respectively. In this paper, we identify key oceanic indexes in the tropical South Atlantic for driving these two rainy seasons. In Eastern NEB, the May-to-July rainfall anomalies present a positive relationship with the previous boreal winter sea surface temperature anomalies (SSTA) in the southeast tropical Atlantic (20 degrees-10 degrees S; 10 degrees W-5 degrees E). This positive relationship, which spread westward along the southern branch of the South Equatorial Current, is associated with northwesterly surface wind anomalies. A warmer sea surface temperature in the southwestern Atlantic warm pool increases the moisture flux convergence, as well as its ascending motion and, hence, the rainfall along the adjacent coastal region. For the Northern NEB, another positive relationship is observed between the February-to-April rainfall anomalies and the SSTA of the previous boreal summer in the Atlantic Nino region (3 degrees S-3 degrees N; 20 degrees W-0 degrees). The negative remote relationship noticeable between the Northern NEB rainfall and the concomitant Pacific Nino/Nina follows cold/warm events occurring during the previous boreal summer in the eastern equatorial Atlantic. The southeastern tropical Atlantic and Atlantic Nino SSTA indexes may, then, be useful to predict seasonal rainfall over the Eastern and Northern NEB, respectively, for about a 6 month leading period. The ability of both southeastern tropical Atlantic and Atlantic Nino SSTA indexes to forecast the Eastern and Northern NEB rainfall, with about a 6 month lead time, is improved when these indexes are respectively combined with the Nino3 (5 degrees S-5 degrees N; 150 degrees-90 degrees W) and the northeast subtropical Atlantic (20 degrees N-35 degrees N, 45 degrees W-20 degrees W), mainly from the 1970's climate shift.

Full Text
File Pages Size Access
Publisher's official version 21 6 MB Open access
Top of the page

How to cite 

Hounsou-Gbo Gbekpo Aubains, Servain Jacques, Araujo Moacyr, Caniaux Guy, Bourles Bernard, Fontenele Diogenes, Martins Eduardo Savio P. R. (2019). SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil. Atmosphere, 10(6), 335 (21p.). Publisher's official version : https://doi.org/10.3390/atmos10060335 , Open Access version : https://archimer.ifremer.fr/doc/00623/73547/