An analysis of the linkage of Pacific subtropical cells with the recharge--discharge processes in ENSO evolution

Results show that the interior STC transport into the equatorial basin through 9°S and 9°N is well connected with equatorial sea surface temperature (SST) (9°S-9°N, 180°-90°W). The highest correlation at interannual time scales is contributed by the western interior STC transport within 160°E and 130°W. It is known that the ENSO recharge-discharge cycle experiences five stages: the recharging stage, recharged stage, warmest SST stage, discharging stage, and discharged stage.

A correlation analysis of interior STC transport convergence, equatorial warm water volume (WWV), wind stress curl, and SST identifies the time intervals between the five stages, which are 8, 10, 2, and 8 months, respectively. A composite analysis for El Niño-developing and La Niña-developing events is also performed. The composited ENSO evolutions are in accordance with the recharge–discharge theory and the corresponding time lags between the above denoted five stages are 4-12, 6, 2, and 4 months, respectively.