The “Spring Predictability Barrier” Phenomenon of ENSO Predictions Generated with the FGOALS-g Model

摘要

Using the sea surface temperature (SST) predicted for the equatorial Pacific Ocean by the Flexible Global Ocean-Atmosphere-Land System Model-gamil (FGOALS-g), an analysis of the prediction errors was performed for the seasonally dependent predictability of SST anomalies both for neutral years and for the growth/decay phase of El Ni?o/La Ni?a events. The study results indicated that for the SST predictions relating to the growth phase and the decay phase of El Ni?o events, the prediction errors have a seasonally dependent evolution. The largest increase in errors occurred in the spring season, which indicates that a prominent spring predictability barrier (SPB) occurs during an El Ni?o-Southern Oscillation (ENSO) warming episode. Furthermore, the SPB associated with the growth-phase prediction is more prominent than that associated with the decay-phase pre-diction. However, for the neutral years and for the growth and decay phases of La Ni?a events, the SPB phenomenon was less prominent. These results indicate that the SPB phenomenon depends extensively on the ENSO events themselves. In particular, the SPB depends on the phases of the ENSO events. These results may provide useful knowledge for improving ENSO forecasting.