Oceananigans-ClimaCore Rectangular Domain Prototype

[LenkaNovak]

(WIP)

The Climate Modeling Alliance

Software Design Issue 📜

Purpose

Showcase a new design for coupling ClimaOcean and ClimaCore-based models. The current ClimaCoupler assumes ClimaCore-based underlying objects, whereas ClimaOcean assumes Oceananigans-based objects, making the two difficult to communicate with each other. With this effort we aim to

• unify the interfaces required to couple a component model to ClimaEarth, where the simulation will be setup
• present a prototype as the basis for CMIP (on which we can iterate based on feedback)

Cost/Benefits/Risks

• b: implements minimal features for ocean/atmosphere coupling
• r: reasonable time investment

People and Personnel

• Lead: @glwagner
• Collaborators: @juliasloan25 @LenkaNovak
• Reviewers:

Components

• ClimaEarth.jl
  • Abstract Simulations from Oceananigans and generalize for use by other models
  • Coupler functionality (for prototyping, keep here, and later will likely be moved to out)
    • regridding
      • stagerring (use Oceananigans)
      • FV-FE (Cartesian available in ClimaCore)
    • masking and area fractions (perhaps not needed here?)
    • prescribed data readers (perhaps not needed here?)
    • flux calculation (NB: flux calculation outside of Atmos only really makes sense for one-timestep coupling)
    • flux accumulation
    • global checks
      • conservation checks: energy, water, mass, momentum
    • performance metrics
    • I/O readers/writers (checkpoints, restarts, diagnostics)
• Atmosphere: a simple dry HeldSuarez that mimics the role of ClimaAmtos
• Ocean: ClimaOcean model setup using ClimaEarth Simulations

Inputs

• ClimaCore HeldSuarez example
• Oceananigans exmaple
• ClimaCoupler functionality in src
• generalised interface for flux exchange (using ideas from https://github.com/CliMA/ClimaCoupler.jl/issues/211 and DoubleTrouble.jl)

Results and Deliverables

• [ ] Simulations in ClimaEarth.jl (QA: oceananigans runs as before)
• [ ] ClimaHeldSuarez with tracers and Simulations interface (QA: same output as the example in ClimaCore)
• [ ] Coupling prototype of the in a rectangular domain (QA: conservation and visual checks match)
• [ ] Detailed CMIP Roadmap (QA: approved by higher management)

Task Breakdown And Schedule

• ClimaHeldSuarez.jl
  • [x] migrate ClimaCore example to ClimaHeldSuarez.jl and ensure it runs
  • [ ] implement ClimaHeldSuarezModel compatible with Simulations
  • [ ] write a CoupedModelComponent method dispatched AtmosModel

• Oceananigans.jl / ClimaOcean.jl

  • [ ] Simulation refactor (move implementation to front of Oceananigans)
  • [ ] Modify Simulation creation process to use ClimaEarth
  • [ ] Develop ocean setup ready for coupling in ClimaOcean
  • [ ] write a CoupedModelComponent method dispatched on OceanModel

• ClimaEarth.jl

  • [ ] Setup CoupedModel, CoupedModelComponent, ... interface
  • [ ] Setup regridding (staggering in Oceananigans, FV-SE in ClimaCore)
  • [ ] Develop EarthSystemModel coupling ClimaOcean.jl and ClimaHeldSuarez.jl
  • [ ] conservation checks
  • [ ] Migrate Simulations from Oceananigans
  • [ ] I/O + simple diagnostics

SDI Revision Log

CC

@tapios @simonbyrne @cmbengue

[tapios]

Could you please add a timeline and how would do what?

[LenkaNovak]

Will do - we're still working on the precise task breakdown, but after that we'll definitely put them in.