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

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 r...

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Main Authors: Gbèkpo Aubains Hounsou-Gbo, Jacques Servain, Moacyr Araujo, Guy Caniaux, Bernard Bourlès, Diogenes Fontenele, Eduardo Sávio P. R. Martins
Format: Article
Language:English
Published: MDPI AG 2019-06-01
Series:Atmosphere
Subjects:
Online Access:https://www.mdpi.com/2073-4433/10/6/335
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spelling doaj-2e709d2eb477487c9587368100ff57ef2020-11-25T01:49:49ZengMDPI AGAtmosphere2073-44332019-06-0110633510.3390/atmos10060335atmos10060335SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast BrazilGbèkpo Aubains Hounsou-Gbo0Jacques Servain1Moacyr Araujo2Guy Caniaux3Bernard Bourlès4Diogenes Fontenele5Eduardo Sávio P. R. Martins6Research Institute for Meteorology and Water Resources (FUNCEME), Av. Rui Barbosa, 1246, Fortaleza-CE 60115-221, BrazilResearch Institute for Meteorology and Water Resources (FUNCEME), Av. Rui Barbosa, 1246, Fortaleza-CE 60115-221, BrazilBrazilian Research Network on Global Climate Change–Rede CLIMA, Av. dos Astronautas 1758, São José dos Campos-SP 12227-010, BrazilCNRM UMR 3589, Météo-France/CNRS, 42 av. G. Coriolis, 31057 Toulouse Cedex 01, FranceInternational Chair in Mathematical Physics and Applications (ICMPA-Unesco Chair), UAC, 072 P.O. Box 50, Cotonou, BéninResearch Institute for Meteorology and Water Resources (FUNCEME), Av. Rui Barbosa, 1246, Fortaleza-CE 60115-221, BrazilResearch Institute for Meteorology and Water Resources (FUNCEME), Av. Rui Barbosa, 1246, Fortaleza-CE 60115-221, BrazilMay-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°−10° S; 10° W−5° 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 Niño region (3° S−3° N; 20° W−0°). The negative remote relationship noticeable between the Northern NEB rainfall and the concomitant Pacific Niño/Niña follows cold/warm events occurring during the previous boreal summer in the eastern equatorial Atlantic. The southeastern tropical Atlantic and Atlantic Niño 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 Niño 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 Niño3 (5° S−5° N; 150°−90° W) and the northeast subtropical Atlantic (20° N−35° N, 45° W−20° W), mainly from the 1970’s climate shift.https://www.mdpi.com/2073-4433/10/6/335Brazilian Northeastrainfallpredictabilitytropical Atlantic
collection DOAJ
language English
format Article
sources DOAJ
author Gbèkpo Aubains Hounsou-Gbo
Jacques Servain
Moacyr Araujo
Guy Caniaux
Bernard Bourlès
Diogenes Fontenele
Eduardo Sávio P. R. Martins
spellingShingle Gbèkpo Aubains Hounsou-Gbo
Jacques Servain
Moacyr Araujo
Guy Caniaux
Bernard Bourlès
Diogenes Fontenele
Eduardo Sávio P. R. Martins
SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
Atmosphere
Brazilian Northeast
rainfall
predictability
tropical Atlantic
author_facet Gbèkpo Aubains Hounsou-Gbo
Jacques Servain
Moacyr Araujo
Guy Caniaux
Bernard Bourlès
Diogenes Fontenele
Eduardo Sávio P. R. Martins
author_sort Gbèkpo Aubains Hounsou-Gbo
title SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
title_short SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
title_full SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
title_fullStr SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
title_full_unstemmed SST Indexes in the Tropical South Atlantic for Forecasting Rainy Seasons in Northeast Brazil
title_sort sst indexes in the tropical south atlantic for forecasting rainy seasons in northeast brazil
publisher MDPI AG
series Atmosphere
issn 2073-4433
publishDate 2019-06-01
description 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°−10° S; 10° W−5° 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 Niño region (3° S−3° N; 20° W−0°). The negative remote relationship noticeable between the Northern NEB rainfall and the concomitant Pacific Niño/Niña follows cold/warm events occurring during the previous boreal summer in the eastern equatorial Atlantic. The southeastern tropical Atlantic and Atlantic Niño 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 Niño 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 Niño3 (5° S−5° N; 150°−90° W) and the northeast subtropical Atlantic (20° N−35° N, 45° W−20° W), mainly from the 1970’s climate shift.
topic Brazilian Northeast
rainfall
predictability
tropical Atlantic
url https://www.mdpi.com/2073-4433/10/6/335
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