Flux‐forced simulations of the paleocirculation of the Mediterranean

Abstract

A series of experiments with an ocean general circulation model of the Mediterranean forced by artificial (but realistic) surface fluxes of heat and freshwater are performed. The model has a stable thermohaline circulation under the baseline fluxes. Small decreases in excess evaporation (8%) produce a linear weakening of the thermohaline circulation with less water formation and smaller strait transports. Levantine Intermediate Water production is shown to be very sensitive to additional freshwater input. The dominant circulation mode in “wetter” climates is one with Adriatic Intermediate Water formation and dispersal, leading to ventilation of intermediate depths of the basin. Although the deep layers are not ventilated, stratification is generally weak. As the excess evaporation decreases, stratification increases. A 60–80% decrease leads to conditions closest to those suggested for sapropel S1, with a west‐east salinity gradient of half of today.