What governs the North Atlantic salinity maximum in a global GCM?

Abstract

[1] Taking advantage of the rapid advance in ocean modeling, this study investigates the sea surface salinity maximum in the North Atlantic, using results from a model of the Consortium for Estimating the Circulation and Climate of the Ocean (ECCO). Salinity budget terms were computed at the model's integration time step and archived as monthly averages. The simulated mixed layer salinity budget provides the first quantitative evidence for the ocean's role in governing the sea surface salinity maximum in the North Atlantic. Our analysis reveals that ocean dynamics explains about half of the sea surface salinity variance, being of equal importance as surface forcing. The sea surface salinity maximum varies both seasonally and interannually, as a consequence of interplay among surface flux, advection, and vertical entrainment. Contribution from eddies and small-scale processes is relatively weak but not negligible. These results may provide useful hints for the design and interpretation of future observations in the region.