Kerchunk success using original CNAPS NetCDF3-64bit-offset files!

[rsignell]

CNAPS fans,
Remember when I said that kerchunk wouldn't work for the original CNAPS NetCDF files because they were NetCDF3 64-bit offset files instead of NetCDF4? Well they do work, thanks to a bit of help from @martindurant!

It's particularly cool, too, because normally you can't even read a NetCDF3 64-bit offset file from object storage. So the strategy is:

• Run kerchunk on a machine that has access to a filesystem with the NetCDF3 64-bit files
• Use the NetCDF3toZarr method with version=2, like so: NetCDF3ToZarr(f,inline_threshold=300, version=2)
• Create a combined.json file (that points to the local references)
• Use the kerchunk.utils function rename_target_files to create a combined reference file combined_s3.json that points to data on S3 object storage instead of local files.
• Create a new Intake catalog item that uses the combined_s3.json references!

Here's proof that it works -- a snapshot from the CNAPS Explorer notebook using this new Intake entry: