Add Kennedy Gruber split form to Atmos

[mwarusz]

This PR aims to bring some of the functionality added in https://github.com/CliMA/ClimateMachine.jl/pull/2188 to the Atmos model. It adds Kennedy Gruber split form of the Atmos model equations using the tendency specification framework.

CC:

@sandreza @charleskawczynski

• [ ] Code follows the style guidelines OR N/A.
• [ ] Unit tests are included OR N/A.
• [ ] Code is exercised in an integration test OR N/A.
• [ ] Documentation has been added/updated OR N/A.

[mwarusz]

bors try

[bors[bot]]

try

Build failed:

• buildkite/climatemachine-ci

[gregorgassner]

I wonder, why you guys choose the Kennedy and Gruber split form?

In my opinion, the Shima_et_al split form is preferable, as it keeps pressure equilibrium preserved and the total energy is consistent to the inner energy and the kinetic energy, but I am curious if there is a particular reason for KG splitting?

[mwarusz]

This PR was meant as a proof of concept for adding split forms to the model. There was no particular reason for implementing KG first, other that its simplicity and that it seemed to be enough for stability.

[gregorgassner]

Thanks for the answer. Makes a lot of sense! Cheers.