Is the Surface Salinity Difference between the Atlantic and Indo-Pacific a Signature of the Atlantic Meridional Overturning Circulation?

Abstract The high Atlantic surface salinity has sometimes been interpreted as a signature of the meridional overturning circulation and an associated salt advection feedback. Here, role oceanic atmospheric processes for creating difference between Indo-Pacific is examined using observations conceptual model. In each basin, zonally averaged data are represented in diagrams relating net evaporation S . data-pair curves – plane share common features both basins. However, slopes generally smaller than Indo-Pacific, indicating weaker sensitivity to variations. To interpret these observations, advective–diffusive model upper-ocean constructed. Notably, relations can be qualitatively reproduced with only diffusive transport. this limit, interbasin caused by spatial structure evaporation, which oceans contains lower wavenumbers that weakly damped observed relationship at reveals no clear influence northward circulation; however, emerges when vertically over upper kilometer. results indicate zonal-mean near-surface shaped primarily pattern transport due wind-driven gyres mesoscale ocean eddies, rather within circulation.