5. Internal Gravity Waves in a Stratified Medium

Let us now turn to movements in the sea column, when surface phenomena play a negligible role. As noted in the initial sections, the density of seawater in the local vicinity of a certain observation point is a function of temperature, pressure, and concentration of impurities at that point. In General, the listed thermodynamic characteristics change in space, which entails a change in density from point to point. In a gravitational field, an inhomogeneous density distribution can be in stable equilibrium only if the gradients of the gravitational potential and density are oppositely directed. In other words, equilibrium occurs if the isopycns (levels of constant density) coincide with the levels of the gravitational potential, and the density decreases with increasing potential.