Spatiotemporal modes of global sea surface temperature variability

This study identifies the salient global modes of sea surface temperature variability based on 145 years of HadISST data. Unlike the traditional mode identification by EOF analysis, a combination of wavelet and EOF analysis is used to extract the leading modes at distinct time scales. The spatial patterns of some well-known regional modes are recovered, with the global connection and frequency content of these modes being revealed. Our analysis indicates that, in terms of global influence, the Pacific Ocean is the major player, and the tropical Pacific is the center of action on various time scales. The Atlantic Ocean has its own outstanding modes, but their global impacts are not as strong as those from the Pacific. The Indian Ocean generally shows a passive response to the Pacific, with a basin-wide pattern in the tropics. Despite some preliminary theoretical attempts, how to elucidate the dynamics underlying the global modes of sea surface temperature variability is still an open question.