Add diagnostic: pbo about mom6

[adcroft]

The current post_data for col_mass uses a temporary "mass" variable which could be subsequently updated to include "pso".

[jkrasting]

Pass in the fluxes type and multiply by 'g'

[jkrasting]

I've run into a problem with adding in the surface pressure to this diagnostic.

See this commit.

I modified the interfaces to pass in the fluxes forcing type, but adding fluxes%p_surf causes the model to SIGSEV. When I looked closer, there are several different varieties of p_surf in the fluxes type.

Any suggestions on how to fix this?

[adcroft]

@jkrasting I think you need to add an "if associated(fluxes%ps_urf)" around the pso contribution.

[jkrasting]

Issuing a pull request.

Here is the output from the ocean_only/global_ALE tests. This diagnostic should also be tested out in the coupled configuration.

And the differences between the /layer and /z examples are less than 0.1%: