Vertical distribution of water properties

Baroclinic flow: vertically varying flow associated with horizontal imhomogegeneities in the statification of oceans. It occurs when levels of constant pressure are inclined to surfaces of constant density. In this case density varies with both depth and horizontal position.

Barotropic flow is a type of circulation (flow) caused by changes in surface elevation. It occurs when levels of constant pressure in the ocean are always parallel to the surface of constant density. The dencity may vary with depth but not with horizontal distance. In that case, constant pressure surfaces are always parallel to the sea surface and the isopycnal surface.