A 215-yr coral δ18O time series from Palau records dynamics of the West Pacific Warm Pool following the end of the Little Ice Age

The West Pacific Warm Pool (WPWP) is a critical region of the global climate system that is closely linked with the El Nio-Southern Oscillation (ENSO). We have generated two monthly resolved coral delta O-18 (delta O-18(CRL)) records from a key region of the WPWP, the Republic of Palau (7'N, 135'E). The isotopic time series span the years 1793-2008 and 1899-2008. During the period of overlap, the two records are well correlated at interannual and annual periods. Multiple lines of evidence demonstrate a strong ENSO signal in Palau delta O-18(CRL). Our records are consistent with previous investigations of twentieth-century tropical Pacific climate variability. We identify a regionally coherent bi-decadal cycle in the WPWP following the termination of the Little Ice Age. The Palau delta O-18(CRL) records show long-term trends towards warming/freshening, suggesting a century scale increase in the strength of the hydrologic cycle associated with the WPWP. Our study represents an important addition to the network of tropical paleo-archives.