In the East Asian Monsoon region, warm ENSO events are seen to be accompanied by an anomalous surface anticyclone over the South China Sea and subtropical western Pacific during the winter season. The circulation changes associated with this feature oppose the winter monsoon over the East Asian coast, thus resulting in warm SST anomalies in that region and above-normal precipitation over southern China. The anticyclone maintains its identity through much of the following spring and summer, during which it migrates steadily eastward. The springtime SST anomalies in the subtropical western Pacific could feedback on the atmospheric circulation, and thereby affect the rainfall anomalies along the Meiyu-Baiu front.
The ENSO forcing also exerts considerable impacts on the atmospheric circulation and precipitation patterns in the Indian Ocean basin through displacements of the near-equatorial Walker Circulation and generation of Rossby-wave modes in the subtropics. Such atmospheric responses modulate the surface fluxes as well as the oceanic circulation in the Indian Ocean, thus leading to prominent SST signals in that region in various phases of the ENSO cycle. Diagnosis of a suite of auxiliary experiments also reveals interesting feedbacks between SST changes in the Indian Ocean sector and the overlying atmospheric circulation.
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