Simple climatic indices for the tropical Atlantic Ocean and some applications

“The first mode is characterized by a north-south interhemispheric gradient in SST with associated changes in trade winds that exerts considerable influence on the regional climate [Moura and Shukla, 1981; Servain, 1991].”

“It is represented by an interhemispheric dipole pattern characterized by crossequatorial SST anomaly gradient, whose nodal line is displaced slightly north of the equator (Servain 1991; Xie and Carton 2004; Chang et al. 2006; Doi et al. 2009; Cabos et al. 2019).”

“Ces changements observés reflètent les variations de la circulation atmosphérique, dans la Zone de Convergence Intertropicale (ZCIT), en particulier de l’interaction entre le système TerreOcéan-Atmosphère (Ardoin-Bardin, 2004 ; Alexander et al., 2006 ; Mahé, 2006).”

“…- Rogers, 1985); Padrão do Pacífico América Norte (PNA - Wallace e Gutzler, 1981); Oscilação Decadal do Pacífico (PDO - Mantua et al., 1997); Modo Meridional do Atlântico (AMM - Servain, 1991); Oscilação Ártica (AO - Thompson e Wallace, 1998) e Oscilação Antártica (AAO - Thompson e Wallace, 2000).”

“The El Nino and Southern Oscillation (ENSO)like inter-decadal oscillation in the Pacific (Zhang et al. 1997; Kachi and Nitta 1997) and the Atlantic inter-hemispheric dipole mode (Moura and Shukla 1981; Servain 1991; Carton et al. 1996) are two important modes of climate variability in the tropics and sub-tropics ident…”

“…et al., 1999)); Oscilação Decadal do Pacífico (ODP - (Mantua et al., 1997)); Oscilação Quase Bienal (QBO - (Angell & Korshover, 1962)); Modo Meridional do Atlântico (AMM - (Servain, 1991)); Oscilação Ártica (AO - (Thompson & Wallace, 1998)) e Oscilação Antártica (OAA - (Thompson & Wallace, 2000)).”

“Servain (1991) found that the tropical Atlantic SST interannual variability may be expressed as a sum of a QB and a 13 year mode.”

“For each region, the normalized area average of SST anomalies were calculated (from January to March) and used to estimate the Sargasso-Tropical Index (STI) proposed by Servain (1991).”

“Essa tabela serviu ano de 1991 (Tabela 3) os resultados associados as variáveis de entrada da Tabela 1, após a aplicação das regras de inferência, apresentaram um nível de pertinência de µ (1,0) para a condição de N para as variáveis analisadas no/sobre o Oceano Tropical, as inferências mostraram um µ (0,67) para a co…”

“The in-phase correlation study between the normalized monthly anomalies of the tropical Atlantic latent heat flux and the convective coverage over NEB during its rainy season (FMAM) shows a dipole signature straddling the ITCZ, quite different from the SST dipole (Servain 1991).”

“Concomitant positive SSTAs in the North and negative SSTAs in the South are referred to as the “positive Atlantic dipole,” and the opposite SSTA pattern is called the “negative Atlantic dipole” (Servain 1991; Carton et al. 1996; Hounsou-Gbo et al. 2019).”

“…linked to global scale phenomena such as El Niño/Southern Oscillation and Atlantic Dipole (Hanstenrath & Heller, 1977; Ropelewski & Halpert, 1987; Servain, 1991; Nobre & Shukla, 1996; Brahmanada Rao et al ., 1997; Souza & Nobre, 1998; Haylock et al ., 2006; Andreoli & Kayano, 2007; Polzin &…”

“The years corresponding to either positive or negative dipole events were chosen based on the index proposed by Servain (1991).”

“Les deux principales variations climatiques sur l’Atlantique tropical s’exercent sur des échelles décennales et multi décennales (Servain, 1991 ; Metha et Delwoth, 1995, 1998) : (1) La première est du même type qu’El Niño dans le Pacifique.”

“The combination of the ITCZ position with other phenomena, like the Atlantic dipole (SST anomalies in the 1990; Servain, 1991).”

“The Atlantic Dipole index was defined following Servain [15].”

“…as seguintes escalas: sazonal (0,25 anos) (Weickmann et al. , 1985), semestral (0,5 anos) (Nascimento et al. , 2017), interanual (1 ano) (Servain, 1991), ENOS (entre 1 e 2 anos) ENOS estendido (2 a 7 anos) (Da Silva, 2017; Da Silva et al. , 2020), Manchas Solares (11 anos) (Kerr, 1996;…”

“However, the peri-Atlantic regions are also concerned since Enoa is also associated with the variability of sea surface temperatures and trade winds over the tropical Atlantic ([6] [7] [8]).”

“1999; Tseng and Mechoso 2001), and into decadal timescale of variability, with sea-surface temperature (SST) varying almost in opposition north and south of the equator (Moura and Shukla 1981; Servain 1991; Houghton and Tourre 1992; Mélice and Servain 2003).”

“It is characterized by a north-south interhemispheric gradient of SST anomalies, and its time scale ranges from interannual to decadal [Moura and Shukla, 1981; Servain, 1991].”

“Because the warming and ascent are centered off the equator, over the subtropical North Atlantic rather than along the equator, this response resembles a positive Atlantic Meridional Mode (AMM) (Servain 1991, Chiang and Vimont 2004).”

“…have been reported for the central-eastern Amazon and NEB, where it is notably associated with anomalous ITCZ displacement (Hastenrath 1984; Servain 1991; Nobre and Shukla 1996; Enfield and Mayer 1997; de Souza et al. 2000; Fu et al. 2001; Wang 2004; Donohoe et al. 2013; Pezzi and…”

“Indices based on oceanic/atmospheric circulation are used to understand the dynamic behaviour of many hydrometeor-ological parameters (Servain 1991; Mathew et al. 2023).”

“The climate signals which used for exploring the relations with warm spells are as follows: North Atlantic Oscillation (NAO) is defined as the normalised pressure difference between a station on the Azores and Iceland (Jones et al.”

“Dentre eles destacam-se o Modo Equatorial, também chamado de El Niño do Atlântico (Zebiak, 1993) e o Modo Meridional, também denominado Gradiente Meridional de TSM ou Dipolo meridional (Moura; Shukla, 1981; Servain, 1991).”

“Entre eles, destacamos os estudos de Moura & SHukla (1981), Hastenrath (1984), Nobre & Shukla (1996), Alves et al. (1997, 2005), Uvo (1989), Souza; Alves & Repelli (1998), Servain (1991), Lucena, Servain & Gomes Filho (2011) e Alves (2012).”

“469 There are some interannual variation modes in SST anomalies in the tropical Atlantic (Melice 470 and Servain, 2003; Servain, 1991), but previous studies have rarely addressed the temperature 471 asymmetry in this basin.”

“…NEB com ENOS, mas estudos observacionais e estatísticos realizadas por Hastenrath e Heller (1977) e simulações numéricas por Moura e Shukla (1981), Servain (1991), Nobre e Shukla (1996), evidenciaram um padrão de anomalias da TSM sobre o oceano Atlântico tropical, comumente chamado de padrão de…”

“Additionally, there is an important decadal variability, associated with a ‘dipole pattern’, that explains roughly a 12% of the variability of the climatology-subtracted Sea Surface Temperature (hereinafter SST) field (Servain, 1991).”

“The inter- hemispheric (or dipole) mode, affects the gradient of the SST between the northern and southern tropics (Servain (1991)) and therefore influences the position of the ITCZ.”

“…1999); - Escala temporal de 11 anos se refere ao ciclo de Manchas solares (Kerr, 1996; Echer, 2003, Molion, 2005) e também ao Dipólo do Atlântico (Servain, 1991; Clauzet e Wainer, 1999); - Escala temporal de 20,2 - 22 anos, associada à Oscilação Decadal do Pacífico (ODP) (Mantua et al., 1997).”

“The equatorial mode has more pronounced variability on the IA timescale (e.g., Zebiak, 1993), while the inter-hemispheric mode is more conspicuous on the DD timescale (e.g., Servain, 1991; Houghton and Tourre, 1992; Carton et al, 1996; Chang et al, 1997; Tourre et al, 1999).”

“Água Preta (1), Amaraji (3), Barra de Guabiraba (4), Barreiros (5), Bonito (8), Cabo de Santo Agostinho (10), Catende (14), Ch ã de Alegria (15), Cort ê s (18), Escada (19), Gameleira (21), Glória do Goitá (22), Igarassu (24), Ipojuca (25), Itapissuma (27), Joaquim Nabuco (31), Maraial (38), Moreno (39), Palmares (41)…”

“…is in contradiction with the spectral analysis of the North and South Atlantic SST indices (Kane, 1998b), where for data for 1964-90 (obtained from Servain, 1991), North Atlantic SST (28° N - 5° N) showed a periodicity of 10.9 years and the South-Atlantic SST (5° N - 20° S) showed a periodicity…”

“It is represented by an interhemispheric dipole pat-94 tern characterized by cross-equatorial SST anomaly gradient, whose nodal line95 is displaced slightly north of the equator (Servain, 1991; Xie and Carton, 2004;96 Chang et al, 2006; Doi et al, 2009; Cabos et al, 2019).”

“…de estudos observacionais que relacionaram a ocorrência de anos secos ou chuvosos na RSANEB com a ocorrência de El Niño ou La Niña no Oceano Pacífico e o sinal do Dipolo no Oceano Atlântico (Hastenrath e Heller, 1977; Moura e Shukla, 1981; Servain, 1993; Nobre e Shukla, 1996; Nobre, 2001).”

“Abstract—J. Servain, a French scientist [ 21 ], proposed a dipole index of a thermal state of waters in the tropical Atlantic.”

“…its projection into the tropical Atlantic (e.g., Enfield and Mayer 1997), the tropical Atlantic meridional SST gradient (e.g., Moura and Shukla 1981; Servain 1991; Chang et al. 1997; Xie 1999; Enfield et al. 1999), the equatorial Atlantic El Niño (e.g., Zebiak 1993; Carton and Huang 1994; Latif…”