Fred Bingham (UNCW)
Variability of the South Pacific Subtropical Surface Salinity Maximum
The high sea surface salinity (SSS) area of the South Pacific subtropical gyre was examined using satellite and in situ data. The mean center of the feature is at 21S,120W. It tilts northwest-southeast and has a size of about 30 degrees in longitude and 8 degrees in latitude as measured by the area of a given surface isohaline (36.258). The area enclosed by this isohaline nearly doubled between 2012 and 2017. The mean SSS within the feature has been increasing as well as maintaining a robust seasonal cycle with maximum SSS in winter (June-July). We tracked the east-west and north-south movement of the feature's centroid. Most significantly, it has been moving northeastward steadily since 2011. We relate this variability to changes in surface freshwater forcing, subtropical gyre strength and position and Ekman transport driven by the wind.