The ocean's saltiness and its overturning

Abstract

Here we explore the relationship between the mean salinity S of the ocean and the strength of its Atlantic and Pacific Meridional Overturning Circulations (AMOC and PMOC). We compare simulations performed with a realistically configured coarse-grained ocean model, spanning a range of mean salinities. We find that the AMOC strength increases approximately linearly with S. In contrast, the PMOC strength declines approximately linearly with S until it reaches a small background value similar to the present-day ocean. Well-established scaling laws for the overturning circulation explain both of these dependencies on S.