| Sea surface temperature (SST) observations since 1870 indicate that the Equatorial Indo-Pacific Sector to Global Warming responds in a zonally asymmetric way: While the Equatorial Pacific shows a weak net cooling in the east and only a weak warming in the west during the 20th century, the Equatorial Indian Ocean exhibits a rather strong warming. This results in a strong increase of the SST gradient between the two ocean basins along the equator. The change in the SST gradient drives an anomalous atmospheric circulation, with an enhancement of Walker Circulation and Hadley Circulation, as inferred from stations data and ensemble experiments with a high-resolution atmospheric general circulation model (AGCM). Anomalous strong precipitation is found over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. The results indicate the importance of inter-basin interactions in shaping the regional climate response to Global Warming. |
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