The Model (4)
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.