RECENT VARIABILITY IN THE SOUTHERN OSCILLATION - ISOTOPIC RESULTS FROM A TARAWA ATOLL CORAL

In the western tropical Pacific, the interannual migration of the Indo nesian Low convective system causes changes in rainfall that dominate the regional signature of the El Nino-Southern Oscillation (ENSO) syst em. A 96-year oxygen isotope record from a Tarawa Atoll coral (1-degre es-N, 172-degrees-E) reflects regional convective activity through rai nfall-induced salinity changes. This monthly resolution record spans t wice the length of the local climatological record and provides a hist ory of ENSO variability comparable in quality with those derived from instrumental climate data. Comparison of this coral record with a hist orical chronology of El Nino events indicates that climate anomalies i n coastal South America are occasionally decoupled from Pacific-wide E NSO extremes. Spectral analysis suggests that the distribution of vari ance in this record has shifted among annual to interannual periods du ring the present century, concurrent with observed changes in the stre ngth of the Southern Oscillation.