This merge moves the 'm_hybi' and 'm_ps' fields to the 'diag_physics' pool. Previously,
'm_ps' was in the 'state' pool, and 'm_hybi' was in the 'mesh' pool. The new location of
these fields better fits with their role in the model, since 'm_ps' really isn't part of the model
prognostic state, and 'm_hybi' isn't part of the MPAS mesh description.
This merge moves the 'm_hybi' and 'm_ps' fields to the 'diag_physics' pool. Previously, 'm_ps' was in the 'state' pool, and 'm_hybi' was in the 'mesh' pool. The new location of these fields better fits with their role in the model, since 'm_ps' really isn't part of the model prognostic state, and 'm_hybi' isn't part of the MPAS mesh description.