Salinity Variations in the Equatorial Pacific during the 2014-15 El Niño

The connection between sea surface temperature (SST) anomalies and El Niño-Southern Oscillation (El Niño) is well understood, due to the availability of SST data and the strong correlation between higher SST anomalies and extreme El Niño conditions. However, the connection between sea surface salinity (SSS) anomalies and El Niño is not well understood, because of the lack of extensive and accurate salinity observations. Global SSS data is now more available from NASA’s Aquarius salinity mission (which ended on June 7, 2015) and ESA’s Soil Moisture and Ocean Salinity (SMOS) mission (still in operation). Previous studies have shown an observed SSS front on the eastern edge of the warm pool in the western Pacific and it’s effects on ENSO. Our analysis utilizes Aquarius, SMOS, and Argo salinity data to examine these SSS variations during the 2014-15 El Niño. We compare the 2014-15 El Niño with previous El Niño years including 2012-13 and 1997-98 using the Simple Ocean Data Assimilation (SODA) reanalysis. Our study demonstrates a clear connection between these salinity variations and the onset, death, and regeneration of the 2014-15 El Niño.