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.