Sea surface salinity variability and its relation to El Niño in a CGCM

We explore the characteristics of sea surface salinity (SSS) variability along with its relation to the El Niño by analyzing results from a coupled general circulation model (CGCM). The CGCM simulates realistic El Niño as well as the mean and the variability of SSS. The SSS anomaly variability is dominated on interannual timescales with its maximum variance in the western tropical Pacific, and large positive SSS anomaly events occur prior to El Niño. The SSS variability and its associated barrier layer thickness are related to the El Niño in the CGCM. Between two subsequent El Niño events a buildup of warm water is evident as indicated by a large barrier layer thickness in the western equatorial Pacific. Weak stratification due to high SSS anomalies helps to discharge the heat stored in the thick barrier layer in the western equatorial Pacific, initiating El Niño development. Further analysis is conducted to support the role of SSS variability associated with El Niño in terms of the variability of heat content anomalies.