Add orographic drag

[jiahe23]

This PR implements the orographic drag following Garner05.

• Obtain topo info and regrid to model grid;
• Implement drag computation;
• Tests (leave the physical tests to a separate PR);
• Documentation;
• Code restructure with recent main updates.

[szy21]

I may change all orographic_drag to orographic_gravity_wave or orographic_gravity_wave_drag to be clear and consistent with nonorographic_gravity_wave. I'll try to review the code later:)

[charleskawczynski]

Hi @jiahe23, sorry that #1231 caused rebase conflicts with this PR. I think we can apply the same sort of pattern that is now used in the main branch:

• Add a orographic_drag CLI flag (done)
• Add an OrographicDrag type (needed)
• Define a model getter for OrographicDrag (in src/model_getters.jl)
• Define orographic_drag_cache(::OrographicDrag, Y) and orographic_drag_cache(::Nothing, Y)
• Replace orographic_drag && CA.orographic_drag_tendency!(Yₜ, Y, p, t) with CA.orographic_drag_tendency!(Yₜ, Y, p, t, p.atmos.orographic_drag)
• Define CA.orographic_drag_tendency!(Yₜ, Y, p, t, ::OrographicDrag) and CA.orographic_drag_tendency!(Yₜ, Y, p, t, ::Nothing)

I can help out if it's not clear

[jiahe23]

Hi @jiahe23, sorry that #1231 caused rebase conflicts with this PR. I think we can apply the same sort of pattern that is now used in the main branch:

• Add a orographic_drag CLI flag (done)
• Add an OrographicDrag type (needed)
• Define a model getter for OrographicDrag (in src/model_getters.jl)
• Define orographic_drag_cache(::OrographicDrag, Y) and orographic_drag_cache(::Nothing, Y)
• Replace orographic_drag && CA.orographic_drag_tendency!(Yₜ, Y, p, t) with CA.orographic_drag_tendency!(Yₜ, Y, p, t, p.atmos.orographic_drag)
• Define CA.orographic_drag_tendency!(Yₜ, Y, p, t, ::OrographicDrag) and CA.orographic_drag_tendency!(Yₜ, Y, p, t, ::Nothing)

I can help out if it's not clear

Thank you for the guideline, @charleskawczynski . It is very helpful. I'll let you know if I have questions making those changes.

[LenkaNovak]

The Overleaf doc looks good! I will continue the review after Charlie's suggested changes (as discussed offline), but here are a couple of minor things I found earlier.

[LenkaNovak]

Hey Jia, the changes look good! There are some loose functions (or at least I couldn't see where they were being used). It would be good to add unit tests - this will also check you're using all new added functions :). Also, do you have a physical test in mind to check it's producing the correct forcing?

[jiahe23]

Hey Jia, the changes look good! There are some loose functions (or at least I couldn't see where they were being used). It would be good to add unit tests - this will also check you're using all new added functions :). Also, do you have a physical test in mind to check it's producing the correct forcing?

Thank, @LenkaNovak ! Good catch from you! The physical test itself seems to be a big project. I have some premature idea and decide to leave it to a separate PR. Let's have a discussion with @szy21 sometime soon.

[jiahe23]

bors r+

[bors]

Build succeeded:

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• docbuild
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