ENSO prediction using an ENSO trigger and a proxy for western equatorial Pacific warm pool movement

The zonal windstress anomaly in the far-western equatorial Pacific (130-160 degreesE) is a precursor to El Nino and La Nina episodes. A linear combination of this windstress with the El Nino index NINO3.4 can be used to predict ENSO successfully. Cross-verified prediction results for NINO3.4 compare favorably with those of leading ENSO prediction models. The model is improved slightly if the time trend in sea surface temperature (SST) near the eastern edge of the western Pacific warm pool is included in the linear combination. Physically this trend is related to zonal equatorial ocean flow which advects the warm pool. The trend therefore aids prediction since it is a precursor to warm pool position and hence ENSO variability.