Teleconnections of the tropical Atlantic to the tropical Indian and Pacific Oceans: a review of recent findings.

Abstract

2 Recent studies found that the tropical Atlantic may exert a considerable teleconnection to both the tropical Pacific and Indian Ocean basins, possibly modulating the Indian summer monsoon and Pacific ENSO events. A warm (cold) tropical Atlantic Ocean forces a Gill-Matsuno-type quadrupole response with a low-level anticyclone (cyclone) located over India that weakens (strengthens) the Indian monsoon circulation. A further analysis shows that the tropical Atlantic Ocean can induce a change in the Indian Ocean SSTs, especially along the coast of Africa and in the western side of the Indian basin. The tropical Atlantic can also influence on the tropical Pacific Ocean via the inter-basin SST gradient variability that is associated with the Atlantic Walker circulation. Although the Pacific El Niño does not correlate with the Atlantic Niño, anomalous warming or cooling of the two equatorial oceans can form an inter-basin SST gradient variability that induces surface zonal wind anomalies over equatorial South America and over some regions of both ocean basins. The zonal wind anomalies act to bridge the interaction of the two ocean basins, reinforcing the inter-basin SST gradient through atmospheric Walker circulations and oceanic dynamics. Thus, a positive feedback seems to exist for climate variability of the tropical Pacific-Atlantic Oceans and atmosphere system, in which the inter-basin SST gradient is coupled to the overlying atmospheric wind. 3