barotropic field of mass

A barotropic field of mass describes a fluid, like the ocean, where surfaces of constant pressure align perfectly with surfaces of constant density. This means that if you were to measure pressure at a certain depth, the density of the water would be the same everywhere along that pressure surface.12

In a barotropic ocean, pressure gradients are uniform with depth, leading to ocean currents that also maintain a consistent speed from the surface to the seafloor. This contrasts with a baroclinic field, where pressure and density surfaces intersect, causing currents to vary with depth. The barotropic condition is a simplified model, as real oceans are typically baroclinic due to variations in temperature and salinity.12