•Hybrid Vertical
 Coordinate Scheme (part 2)
 –In the deep ocean, the isopycnic-level coordinate transition is performed
 as follows:
 •If the density of a
 given layer does not equal the isopycnic reference density, the interfaces bounding the layer are adjusted
 to return the density to its reference
 value
 –If the layer is too
 light, the interface below is moved downward so that the entrained denser water returns the density
 to its reference value
 –If the layer is too dense, the interface above is moved upward in the same manner
 •If minimum coordinate
 separation is violated near the ocean surface, the cushion function is used to re-calculate the
 vertical coordinate location, prohibiting
 the restoration of isopycnic conditions.
 •Two of the thermodynamical variables T, S, and density are mixed across the moving interfaces (user selectable), with the
 third calculated from the equation of
 state. If T and S are mixed, exact isopycnal
 density is not restored, but repeated application keeps the error small.