Add scripts to preprocess the GHCN snow data

[jiaruidong2017]

Description

This PR adds a ghcn_snod2ioda.py script to processes the GHCN data in csv format to IODA-format files for snow DA in the global-workflow.

Companion PRs

This PR depends NOAA-EMC/jcb-gdas#220, NOAA-EMC/DA-utils#53, and NOAA-EMC/global-workflow#4388
This PR contributes NOAA-EMC/global-workflow#4386

Issues

Resolves #2018

Automated CI tests to run in Global Workflow

• atm_jjob
• C96C48_ufs_hybatmDA
• C96C48_hybatmsnowDA
• C96_gcafs_cycled
• C48mx500_3DVarAOWCDA
• C48mx500_hybAOWCDA
• C96C48_ufsgsi_hybatmDA
• C96C48_hybatmDA

[Copilot]

Pull request overview

This PR adds preprocessing capabilities for GHCN (Global Historical Climatology Network) snow depth observations by introducing a Python converter script that transforms GHCN CSV data into IODA-format NetCDF files for use in snow data assimilation workflows.

• Adds ghcn_snod2ioda.py script to convert GHCN snow depth CSV data to IODA format
• Implements data filtering for valid snow depth observations and date selection
• Adds YAML configuration template for GHCN data preparation workflow

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 20 comments.

File	Description
ush/snow/ghcn_snod2ioda.py	New converter script that reads GHCN CSV data, merges with station metadata, filters observations, and outputs IODA-format NetCDF files
parm/snow/prep/prep_ghcn.yaml.j2	Configuration template defining file staging and conversion workflow for GHCN snow data preprocessing

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[ClaraDraper-NOAA]

@jiaruidong2017 Thanks for doing this. I added a co-pilot review above. I left it in case there's anything you want to respond to, but I would probably ignore most of it.

In particular, it looks like you've copied the GHCN to IODA converter from the JEDI repo. Did you need to make any changes to it to run outside of JEDI? Co-pilot has suggested some clean-up (all good suggestions), but I'm wondering if we want to try to keep this version the same as the one in the JEDI repo. @CoryMartin-NOAA What do you think?

[jiaruidong2017]

@jiaruidong2017 Thanks for doing this. I added a co-pilot review above. I left it in case there's anything you want to respond to, but I would probably ignore most of it.

In particular, it looks like you've copied the GHCN to IODA converter from the JEDI repo. Did you need to make any changes to it to run outside of JEDI? Co-pilot has suggested some clean-up (all good suggestions), but I'm wondering if we want to try to keep this version the same as the one in the JEDI repo. @CoryMartin-NOAA What do you think?

Thanks @ClaraDraper-NOAA for launching the co-polit review. I agree that we should keep this version consistent with the one in the JEDI repo unless we plan to apply the same changes in JEDI repo as well. Wait for @CoryMartin-NOAA’s suggestions.

[CoryMartin-NOAA]

I think we can largely ignore the Copilot suggestions and keep it consistent with what is in ioda-converters. IMO all of the ioda-converters are not completely robust, so I would be supportive of rewriting this in C++ (eventually) so that we can leverage IODA directly and not through the multi layered Python API.

[CoryMartin-NOAA]

@jiaruidong2017 I think we just need the jcb-gdas hash updated here, then I can merge this, and then update the GDASApp hash in your workflow PR