Geophysical Research Letters

Rapid termination of the 2006 El Niño and its relation to the Indian Ocean

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Abstract

[1] We investigated the rapid termination of the 2006 El Niño using observed data and a coupled ocean-atmosphere general circulation model (CGCM). Observed data showed development of an anomalous South Indian Ocean (SIO) anticyclone associated with the concurrent Indian Ocean Dipole during September–November 2006. At the end of 2006, the eastward retreat of the SIO anticyclone in response to the Indian Ocean warming generated an easterly anomaly over the western Pacific, and the resultant oceanic upwelling Kelvin wave terminated the El Niño. CGCM experiments indicated that the formation of the SIO anticyclone was influenced remotely by the Pacific Ocean SST anomalies, and that the easterly anomaly over the western Pacific at the end of 2006 was reinforced by the Indian Ocean SST anomalies. These results suggest that interactive feedback between the Indian and Pacific Oceans helped the rapid termination of the 2006 event.

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