Add zenith angle to sea ice albedo calculations

[Dan Copsey (DanCopsey)]

PR Summary

Sci/Tech Reviewer:
Code Reviewer: Erica Neininger (@ericaneininger)

Adds a zenith angle dependence to the calculation of albedo for bare sea ice, snow on sea ice and melt ponds. See issue #88 for more details.

• closes Add zenith angle dependence to sea ice albedo calculations #88

Code Quality Checklist

(Some checks are automatically carried out via the CI pipeline)

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid undertanding and enhance the
  readability of the code
• My changes generate no new warnings
• If editing rose-meta/jules-shared then have you supplied a linked UM PR?

Testing

• I have tested this change locally, using the JULES rose-stem suite
• If shared files have been modified, I have run the UM and LFRic Apps rose
  stem suites
• If any tests fail (rose-stem or CI) the reason is understood and
  acceptable (eg. kgo changes)
• I have added tests to cover new functionality as appropriate (eg. system
  tests, unit tests, etc.)

trac.log

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if applicable)

Performance Impact

• Performance of the code has been considered and, if applicable, suitable
  performance measurements have been conducted

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance
  of Generative AI tool name (e.g., Met Office Github Copilot Enterprise,
  Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the
  Simulation Systems AI policy
  (including attribution labels)

Documentation

• Where appropriate I have updated documentation related to this change and
  confirmed that it builds correctly

Approvals

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owners.

Technical

• JULES Code Owner
• OpenMP
• River Routing
• Rose Stem
• Rose Metadata
• Upgrade Macros

Scientific

• Surface
• Hydrology
• Vegetation
• Veg3 RED Demography
• Biogechemistry
• Biogenic fluxes
• Fire
• Lakes
• Evaluation
• Imogen

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

Please alert the code reviewer via a tag when you have approved the SR

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• CLA compliance has been confirmed
• Code quality standards have been met
• Tests are adequate and have passed
• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[github-actions]

Hello Dan Copsey (@DanCopsey)! 👋

Thank you for your contribution. Since this is your first time contributing to this repository, we ask that you sign our Contributor Licence Agreement (CLA).

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To agree to the CLA, please add your details (GitHub username, Real Name, Affiliation, and Date) to the CONTRIBUTORS.md file (create one, if required) in the development branch for this PR. After signing the CLA, you won't need to do this again for future PRs.