Understanding Lead Times of Warm Water Volumes to ENSO Sea Surface Temperature Anomalies

Abstract

The equatorial Pacific warm water volume (WWV) and western equatorial Pacific WWV (WWVw) are two important long-lead time El Niño-Southern Oscillation (ENSO) event precursors. Here, we utilize the recharge-discharge oscillator framework to obtain the analytical solution of WWV and WWVw lead times to ENSO sea surface temperatures (SSTs). Both WWV and WWVw lead times show a strong dependence on the inherent ENSO periodicity, whereas WWV lead time is further modulated by the air-sea coupling strength and ENSO SST spatial pattern. The derived solution is able to explain observed decadal variations in lead times of WWV to SST in terms of variations in ENSO periodicity and air-sea coupling strength.