Added recipe, diagnostics and documentation for Schlund et al., ESD (2020)

[schlunma]

This PR adds the recipe, diagnostic scripts and documentation for Schlund et al., ESD (2020).

Since I used this exact code for the analysis in the paper, a thorough scientific review is not necessary. Please note that due to #1903 the recipe needs to be run with the --check-level ignore option.

Depends on #1874.

• Closes Add recipe for Schlund et al., ESD (2020) #1916
• Link to documentation: https://esmvaltool--2015.org.readthedocs.build/en/2015/recipes/recipe_schlund20esd.html

---

Before you get started

• ☝ Create an issue to discuss what you are going to do

Checklist

It is the responsibility of the author to make sure the PR is ready to review. The icons indicate whether the item will be subject to the 🛠 Technical or 🧪 Scientific review.

• 🛠 PR has a descriptive title for the changelog
• 🛠 Code follows the style guide
• 🛠 Documentation is available
• 🛠 YAML files pass pre-commit or yamllint checks
• 🛠 Circle/CI tests pass
• 🛠 Codacy code quality checks pass
• 🛠 Documentation builds successfully on readthedocs

New or updated recipe/diagnostic:

• 🛠 Provenance information has been added
• 🛠 New dependencies are added to the project requirements
• 🧪 Documentation for the recipe/diagnostic clearly describes what it calculates from a scientific point of view
• 🧪 Recipe runs successfully on @esmvalbot or some other machine without modification
• 🧪 Figure(s)/data look as expected
• 🧪 Code is well documented and scientifically sound

---

To help with the number pull requests:

• 🙏 We kindly ask you to review two other open pull requests in this repository

[axel-lauer]

@schlunma: I am giving up on trying to install ESMValCore v2.2 for testing. I'll take a look once ESMValCore v2.2 has been released and I succeed in setting up an environment again.

[schlunma]

Absolutely no worries @axel-lauer! I will ping you again when ESMValCore is released and #1874 is merged.

[bettina-gier]

Recipe ran fine, produces the plots from the paper, documentation clear and concise. Provenance runs correctly as well ;)

My only comment would be that

Please note that due to #1903 the recipe needs to be run with the --check-level ignore option.

this should be noted in the documentation or the header of the recipe otherwise the knowledge might get lost down the line before the issue is fixed.

And from the Codacy issues, I guess you could fix this one:
third party import "from esmvalcore.cmor.fixes import add_plev_from_altitude, add_sigma_factory" should be placed before "import esmvaltool.diag_scripts.emergent_constraints as ec"
in esmvaltool/diag_scripts/emergent_constraints/ecs_scatter.py

Also can you rerun the checks? The iris3 env is merged to master now ;)

[schlunma]

Thanks for the review! 😊

I added the caveat to the documentation.

About the Codacy issue: my local prospector and isort complain if I change the order of that import, so I guess I just leave it as is 😃

[schlunma]

@valeriupredoi would you have time for a brief technical review of this? The vast majority of changes are related to documentation (there's no real new diagnostic here), so this should not take long! Thanks 🍻

[valeriupredoi]

@valeriupredoi would you have time for a brief technical review of this? The vast majority of changes are related to documentation (there's no real new diagnostic here), so this should not take long! Thanks beers

sure, will look at it in 10min 👍

[valeriupredoi]

@schlunma looks good, I didn't read carefully all that documentation, since I trust all is good from a scientific point (I wouldn't know that stuff anyway). Two questions: did you really want to remove the pointers to the seaborn api documentation and could you pls fix that import complaint from Codacy? 🍺

[schlunma]

Thanks for the review!! 👍

1. The information in the documentation was duplicate since :func:'seaborn.set' already points to the link I removed.
2. When I change the order my local prospector complains about it and isort automatically changes it back in pre-commit, so not sure what's correct here 😄