The salt flux at the ocean surface is
where is the evaporation and the precipitation rates at the surface and is the sea surface salinity. is of course related to the latent heat flux .
An alternative to equations (55) and (56) is to prescribe the sea surface temperature and salinity, if known:
Yet another alternative is to damp the surface values of and S to the sea surface values with a time lag
Conditions (57) and (58) are most often used in climatological simulations, while equation (55) and (56) are useful for driving the ocean with synoptic momentum and buoyancy fluxes.