Oceanic variability that interacts with the El Niño/Southern Oscillation (ENSO) has been well identified in most ocean basins; however, the effect of variability over the South Atlantic (SA) on the ENSO is unknown. This study demonstrates that dominant mode of subtropical SA sea surface temperature (SST) variability during the boreal winter, referred to as the South Atlantic Subtropical Dipole (SASD), contributes to occurrence of an El Niño a year later. During a positive SASD, low-tropospheric anticyclonic circulation anomalies over the mid-latitude SA reduce convective activities over southeastern South America. The low-tropospheric divergence anomalies associated with the reduced convection attenuate the occurrence of South American Low-Level Jet, and moisture supply is directed along the South Atlantic Convergence Zone (SACZ). The increased precipitation over the SACZ leads to an anomalous surface easterly that lowers the SST over the equatorial Atlantic and eventually modulates the zonal Walker circulation, thereby favoring El Niño development.

中文翻译：

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南大西洋变化与厄尔尼诺/南方涛动之间的流域间相互作用

与厄尔尼诺/南方涛动 (ENSO) 相互作用的海洋变率已在大多数海洋盆地中得到很好的识别；然而，南大西洋 (SA) 的变率对 ENSO 的影响尚不清楚。这项研究表明，北半球冬季的亚热带 SA 海面温度 (SST) 变化的主要模式，称为南大西洋副热带偶极子 (SASD)，有助于一年后发生厄尔尼诺现象。在正SASD期间，中纬度SA上空的低对流层反气旋环流异常减少了南美洲东南部的对流活动。与减少对流相关的低对流层散度异常减弱了南美低空急流的发生，水分供应沿南大西洋辐合带（SACZ）定向。