NOAA/WDS Paleoclimatology - Aulong Island, Drum Can Island - Oxygen Isotope Data

Seasonal sea surface salinity (SSS) records can be of great value in reconstructing El Nino/Southern Oscillation (ENSO) variability in the equatorial Western and Central Pacific, a region where ENSO-related evaporation and precipitation (E-P) changes are dramatic. The d18O values of coral skeleton (d18Ocoral) reflect seawater d18O (d18Oseawater) changes, which in tropical oceans are also generally influenced by E-P changes. Therefore, d18Ocoral is a good indicator of rainfall and ENSO variability. We present biweekly data from Palau, in the northern part of the Western Pacific Warm Pool, for the period 1998-2000, which indicate a strong quantitative relationship between d18Ocoral, sea surface temperature, d18Oseawater and SSS. The coral skeletal d18O values documented the SSS changes after the 1997-98 El Nino; therefore, d18Ocoral can be used to estimate paleosalinity changes. However, the slope of the d18Oseawater - SSS relationship cannot be assumed to be constant throughout the tropics, making site-specific calibrations is essential.