| Evolution of the two types of Atlantic Niño. Composites of (a) February-March (FM, initiation stage), (b) April-May (developing stage), (c) JuneJuly (mature stage) mean SSTA (shading, °C) and 850hPa wind anomalies (vectors, m s −1 ) during CAN events. d-f Same as a-c, but for EAN events. The purple line indicates the equator. Hatching and gray arrows represent anomalies that are not statistically significant at the 95% confidence level.

Contexts in source publication

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... further analyze developing processes of the two Atlantic Niño types, we examine their associated anomalies in different stages (Fig. 2). In the initial stage of the CAN, significant warming appears in the South Atlantic, accompanied by westerly wind anomalies in the South tropical Atlantic (Fig. 2a). The warming in the central Atlantic and the westerly wind anomalies in the western equatorial Atlantic further strengthen during the developing stage, and reach their ...

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... further analyze developing processes of the two Atlantic Niño types, we examine their associated anomalies in different stages (Fig. 2). In the initial stage of the CAN, significant warming appears in the South Atlantic, accompanied by westerly wind anomalies in the South tropical Atlantic (Fig. 2a). The warming in the central Atlantic and the westerly wind anomalies in the western equatorial Atlantic further strengthen during the developing stage, and reach their peaks during the mature stage (Fig. 2b, c). During the EAN, the initial warming is negligible in the South Atlantic. Instead, there is significant warming in the eastern ...

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... stage of the CAN, significant warming appears in the South Atlantic, accompanied by westerly wind anomalies in the South tropical Atlantic (Fig. 2a). The warming in the central Atlantic and the westerly wind anomalies in the western equatorial Atlantic further strengthen during the developing stage, and reach their peaks during the mature stage (Fig. 2b, c). During the EAN, the initial warming is negligible in the South Atlantic. Instead, there is significant warming in the eastern tropical Atlantic coastal region, along with northwesterly anomalies over the eastern tropical Atlantic (Fig. 2d). During the developing stage, the coastal warming intensifies and extends toward the equator, ...

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... Atlantic further strengthen during the developing stage, and reach their peaks during the mature stage (Fig. 2b, c). During the EAN, the initial warming is negligible in the South Atlantic. Instead, there is significant warming in the eastern tropical Atlantic coastal region, along with northwesterly anomalies over the eastern tropical Atlantic (Fig. 2d). During the developing stage, the coastal warming intensifies and extends toward the equator, where the extended warming induces westerly wind anomalies (Fig. 2e). The warming and westerly wind anomalies continue to strengthen and develop into the EAN at its mature stage. (Fig. 2f). ...

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... in the South Atlantic. Instead, there is significant warming in the eastern tropical Atlantic coastal region, along with northwesterly anomalies over the eastern tropical Atlantic (Fig. 2d). During the developing stage, the coastal warming intensifies and extends toward the equator, where the extended warming induces westerly wind anomalies (Fig. 2e). The warming and westerly wind anomalies continue to strengthen and develop into the EAN at its mature stage. (Fig. 2f). ...

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... with northwesterly anomalies over the eastern tropical Atlantic (Fig. 2d). During the developing stage, the coastal warming intensifies and extends toward the equator, where the extended warming induces westerly wind anomalies (Fig. 2e). The warming and westerly wind anomalies continue to strengthen and develop into the EAN at its mature stage. (Fig. 2f). ...

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... in the central and eastern basins during the CAN and EAN, respectively (Fig. 3d, h). This effect is associated with the Ekman feedback and thermocline deepening (Figs. S1 and S2) [45][46][47] , both of which contribute to the differences in the warming patterns between the CAN and EAN, which is further linked to the different wind anomalies (Fig. 2b, e). Westerly wind anomalies during the CAN primarily occur over the westerncentral basin, suppressing upwelling and favoring the deepening of the thermocline in the region, whereas during the EAN, the wind anomalies and associated anomalous downwelling and thermocline changes are stronger over the eastern equatorial Atlantic (Fig. S3). ...

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... term significantly contributes to the warming in the southwestern tropical Atlantic and the northeastern basin warming during the CAN and EAN, respectively. Moreover, northerly wind anomalies induced by coastal warming in the eastern basin further transport warm water from north of the equator to the southeastern Atlantic, causing coastal warming (Figs. 2e and ...

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... to the development of most (7/10) CAN events, significant warming is observed in the subtropical South Atlantic (Fig. 2a), inducing an interhemispheric thermal contrast. Consequently, prominent crossequatorial northerly wind anomalies emerge over the tropical Atlantic. Under the influence of the Coriolis force, the anomalous northerlies turn into westerly anomalies over the equatorial southern Atlantic. This result is supported by atmospheric model ...

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... contrast, warming in the south tropical Atlantic is insignificant during the initiation stage of the EAN (Fig. 2d). Instead, the precursors of the EAN are similar to those of the canonical El Nino 48-50 , with warm SSTAs first appearing in the eastern basin along the western coasts of Africa, which subsequently develops in the eastern tropical Atlantic in the following season. Previous studies suggest that oceanic equatorial Kelvin waves can cause ...

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... Previous studies suggest that oceanic equatorial Kelvin waves can cause the Atlantic Niño by deepening the thermocline in the eastern basin and resulting in warm SSTA in the region 31,32 . Since the mean thermocline depth is shallower off the coasts of West Africa (Fig. 6b), surface warming tends to emerge in the coastal region, consistent with Fig. 2d (Fig. 5). In contrast, only one CAN event appears to be associated with the oceanic waves (Fig. S8). For the CAN, the southeast wind anomalies in the eastern Atlantic, induced by the warming in the central basin, weaken the downwelling Kelvin waves propagating to the eastern Atlantic and coastal region, eventually causing the warming ...

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... assess the contributions of wind anomalies in the eastern Atlantic during the CAN, a linear ocean model with a horizontal resolution of 0.25° is used in this study 69 . Two sets of experiments are conducted, each forced by surface wind stress anomalies during AM and JJ of the CAN events (Fig. 2b, c). Each set consists of three experiments driven by the whole equatorial Atlantic (100°W to 20°E, 7.5°S to 7.5°N), equatorial western Atlantic (100°W to 7.5°E, 7.5°S to 7.5°N), and eastern Atlantic (7.5°E to 20°E, 7.5°S to 7.5°N) wind stress anomalies, respectively. The numerical experiments are integrated for 10 years, with the last 5 ...