32-bit physics with FV3_RAP

[SamuelTrahanNOAA]

This adds support for 32-bit physics to the FV3, based on prior work on the Neptune model. The 64-bit physics should not change results. Presently, the 32-bit physics are incompatible with MOM6 because it has conflicting stochastic_physics precision requirements, so MOM6-coupled configurations must use 64-bit physics.

Issues

ufs-community/ufs-weather-model#1288

Dependencies

NCAR/ccpp-physics#930
NOAA-GFDL/GFDL_atmos_cubed_sphere#193
earth-system-radiation/rte-rrtmgp#180 this was already merged

[junwang-noaa]

@SamuelTrahanNOAA For the overloading capability, would you like to try the Fortran polymorphic class? Please see example:

https://github.com/NOAA-GFDL/FMS/pull/962/files#diff-e76bad5442df93e413ddc44d0e23dd628f667843a955bb471d5ff5ea036cd944

[SamuelTrahanNOAA]

@SamuelTrahanNOAA For the overloading capability, would you like to try the Fortran polymorphic class? Please see example:

https://github.com/NOAA-GFDL/FMS/pull/962/files#diff-e76bad5442df93e413ddc44d0e23dd628f667843a955bb471d5ff5ea036cd944

I think the resulting code would be just as complex, and would use features many developers don't know. If Fortran had templates or generics, I would use that, but it doesn't.

[SamuelTrahanNOAA]

@SamuelTrahanNOAA For the overloading capability, would you like to try the Fortran polymorphic class? Please see example:
https://github.com/NOAA-GFDL/FMS/pull/962/files#diff-e76bad5442df93e413ddc44d0e23dd628f667843a955bb471d5ff5ea036cd944

I think the resulting code would be just as complex, and would use features many developers don't know. If Fortran had templates or generics, I would use that, but it doesn't.

I see no obvious "best way" of cleaning up this code, so I made an issue here:

#559

We can discuss a better option in that issue.

[jkbk2004]

@SamuelTrahanNOAA so its this pr's turn to update and merge.

[SamuelTrahanNOAA]

The atmos_cubed_sphere and ccpp/physics point to the authoritative branches now. This PR is ready for final review and merge.

[SamuelTrahanNOAA]

I need a second review before this can be merged.