Synchronous Chlorophyll-a and Sea Surface Salinity Variability in the Equatorial Pacific Ocean

Abstract

Using chlorophyll-a (Chl-a) concentration data derived from the Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-orbiting Partnership, the in situ measurements from the tropical ocean atmosphere moorings, and the sea surface salinity (SSS) data from the Soil Moisture Active Passive mission and Aquarius satellite, we report synchronous Chl-a and SSS variability in the Equatorial Pacific Ocean on the daily and monthly bases. During the El Niño event in 2015, a decrease in Chl-a and SSS occurred and developed within the same timeframe, and possessed similar spatial patterns across the Equatorial Pacific Ocean. Enhanced Chl-a and SSS coincided and colocated (in timing, location, spatial coverage, and extent) during the La Niña event in 2020. In contrast, sea surface temperature variability did not relate to Chl-a and SSS variability across the Equatorial Pacific Ocean. Chl-a and SSS were found to covary on the daily basis driven by the tropical instability waves. The mechanism that caused the synchronous Chl-a and SSS variability in the Equatorial Pacific Ocean on both the daily and monthly bases is addressed and discussed.

Keywords

• Biological activity
• chlorophyll-a variability
• El Niño Southern Oscillation (ENSO)
• Equatorial Pacific Ocean
• sea surface salinity (SSS)
• sea surface temperature (SST)