CHARACTERIZING EL NIñO SOUTHERN OSCILLATION (ENSO) VARIABILITY USING SR/CA-BASED SST AND δ18O-DERIVED SSS FROM THE SOUTHWEST PACIFIC

The scarcity of oceanic observations limits the reliability of model simulations and our scientific understanding of climate phenomena such as the El Niño Southern Oscillation (ENSO), a prominent source of interannual variability in atmospheric-oceanic circulation. Phases of ENSO shift the position of the South Pacific Convergence Zone (SPCZ), impacting precipitation patterns, and resulting in anomalous SSS values across the region. This research places new Sr/Ca and δ18O measurements from a Porites coral core, ATC13019B, collected from Aitutaki (18.85°S, 159.79°W) in context with pre-existing Sr/Ca and δ18O data series from the southwest tropical Pacific and PMIP3 simulations. Using reconstructed SST anomalies produced from ATC13019B Sr/Ca measurements, a residual SSS anomaly signal can be deconvolved from δ18O anomalies to deduce the spatial and temporal variability of ENSO from the late 19^th century and into the 20^th century.