Use consistent suffix for cycled UFSDA netcdf files

[RussTreadon-NOAA]

The current implementation of UFSDA DA uses two suffixes for netcdf files: .nc and .nc4. It seems preferable for the sake of consistency to use a single suffix.

Discussion among a subset of DAD UFSDA DA marine and atm developers is leaning towards .nc. Both GDASApp and g-w reference cycled UFSDA netcdf files. As such, this discussion is opened to get the g-w perspective.

[RussTreadon-NOAA]

Add @CoryMartin-NOAA , @guillaumevernieres , @ADCollard , and @emilyhcliu for awareness.

[aerorahul]

https://docs.unidata.ucar.edu/netcdf-c/current/faq.html#:~:text=NetCDF%20files%20should%20have%20the,nc%22.

[RussTreadon-NOAA]

Thanks @aerorahul

What convention should be used for the names of netCDF files?
NetCDF files should have the file name extension ".nc". The recommended extension for netCDF files was changed from ".cdf" to ".nc" in 1994 in order to avoid a clash with the NASA CDF file extension, and now it also avoids confusion with "Channel Definition Format" files.

.nc is the netcdf team recommendation.

[aerorahul]

@RussTreadon-NOAA Is this discussion reaching a resolution?

[RussTreadon-NOAA]

@aerorahul: .nc is the recommended suffix from the netcdf team. Do EE2 standards offer any guidance?

[aerorahul]

No. .nc is fine.

[RussTreadon-NOAA]

OK. Just need everyone to be aware of this convention and ensure that their netcdf files use the .nc suffix.

Closing discussion.