Atmospheric and oceanic evidences of El Nino Southern Oscillation events in the south central Pacific Ocean from coral stable isotopic records over the last 137 years

We measured delta(18)O and delta(13)C in Porites lutea collected in the Moo rea lagoon where the instrumental records show that an El Nino-Southern Osc illation (ENSO) event implies both a cloud cover decrease and a weak sea su rface temperature(SST) increase. Two proxies allow an ENSO record to be rec onstructed at Moorea: the annual delta(13)C anomaly, associated with the So uth Pacific Convergence Zone motion, and an annual delta(18)O anomaly showi ng increased SST. The frequency bands exhibited by the singular spectral an alysis (SSA) and the multitaper method of the annual delta(18)O and delta(1 3)C records are centered on 2.5 and 5.2 years and 2.4 and 3.2 years, respec tively, which are the main ENSO modes. We used SSA to reconstruct ENSO even ts at Moorea over the past 137 years. Results indicate that climate variabi lity at this site is strongly affected by ENSO events.