MetOffice / MetOffice/cube_helper
Correct iris faulty generation of altitude bounds when reading files with hybrid height coordinate
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 3
- Forks
- 4
- PR merge metrics
- No merged PRs in 30d
Description
There is a long running discussion around whether the bounds on the vertical coordinate are being appropriately set on CMORised data; PCMDI/cmor#177 and SciTools/iris#3678.
At present any iris v2 code will give spurious bounds as it won't read in the b_bounds (a.k.a. sigma bounds) due to the lack of variable attributes. This leads to invalid altitude bounds over orography as the point values are used instead.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing the discussion in PCMDI/cmor#177 and SciTools/iris#3678, then trace how Iris v2 reads hybrid-height files and handles the b_bounds variable and its attributes. Reproduce the issue with CMORised data and verify that altitude bounds over orography are no longer derived from point values.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100