Tropical Atlantic salinity variability: New Insights from SMOS
Tzortzi, Eleni1; Gommenginger, Christine2; Srokosz, Meric2; Josey, Simon2
1National Oceanography Centre Southampton- University of Southampton, UNITED KINGDOM; 2National Oceanography Centre Southampton, UK, UNITED KINGDOM
Observations from the SMOS satellite are used to reveal new aspects of Tropical Atlantic sea surface salinity (SSS) variability. Over an annual cycle, the variability is dominated by eastern and western basin SSS 'poles', with seasonal ranges up to 6.5 pss, that vary out of phase by 6 months and largely compensate each other. A much smaller SSS range (0.08 pss) is observed for the region as a whole. The dominant processes controlling SSS variability are investigated using GPCPv2.2 precipitation (P), OAFlux evaporation (E) and river flow (R) from the Dai and Trenberth and the ORE-HYBAM datasets. For the western pole, SSS varies in-phase with P and lags R by 1-2 months; a more complex relationship holds for the eastern pole. Furthermore, our analysis examines whether the seasonal compensation of SSS between the eastern and western poles of the Tropical Atlantic may continue to hold at multi-annual timescales. The synthesis of novel satellite SSS data with E, P and R enables a new approach to determining variability in Tropical freshwater fluxes and its potential impacts on the Atlantic ocean circulation.