Evolution of the Upper Ocean Salinity during the SPURS campaigns

Observations collected during the Salinity Processes Upper-ocean Regional Study (SPURS) field campaign in the subtropical Atlantic Ocean are used to identify and quantify the processes responsible for deepening the surface mixed layer in Winter, and restratification in the Spring and Summer. During the year-long campaign, three autonomous gliders collected several upper ocean (0-250) microstructure profiles per day, as well as resolving the temperature and salinity fields over the top 1000m. Specifically, during the first 6 months of SPURS, about 2500 profiles of temperature variance dissipation rate were collected, processed autonomously on board the vehicles, and transmitted in near real-time. These direct estimates of dissipation constrain mixed layer evolution and evaluate the impact of mixing due to internal waves and lateral intrusions at the base of the mixed layer.

We also present an overview of the upcoming SPURS-2 campaign in the eastern equatorial Pacific. Together with moored and other autonomous components, Seagliders will allow us to resolve salt storage and its horizontal and vertical advection, and quantify diapycnal mixing of salt by small-scale turbulence. The SPURS-2 campaign will provide a direct view of the processes by which the ocean spreads and integrates freshwater from precipitation.