Two-Year Dynamical Predictions of ENSO Event Duration during 1954–2015

Abstract El Niño and La Niña events show a wide range of durations over the historical record. The predictability event duration has remained largely unknown, although multiyear could prolong their climate impacts. To explore duration, ensemble forecasts are conducted with Community Earth System Model, version 1 (CESM1). 10–40-member initialized observed oceanic conditions on March, June, November each year during 1954–2015; spread is created through slight perturbations to atmospheric initial conditions. CESM1 predicts individual lead times ranging from 6 25 months. In particular, in November, near first peak or Niña, can skillfully predict whether continues second 1-yr time. occurrence be predicted even earlier up months, especially when they preceded by strong Niño. arises thermocline depth anomalies equatorial Pacific, as well sea surface temperature within outside tropical Pacific. forecast error growth, other hand, originates mainly variability North Pacific boreal winter. high indicates potential for extending 12-month operational one additional year.