BSSP126 fails because NETCDF File is actually an HDF5

[Sameer Agarwal]

I am trying to run cesm 2.1.3 using the BSSP126 compset and it fails claiming

NetCDF: Unknown file format pio_support::pio_die:: myrank= -1 : ERROR: ionf_mod.F90: 235 : NetCDF: Unknown file format

I was able to track this down to

ozone_strataero_WACCM_L70_zm5day_2015-2100_SSP126_c190221.nc

which even though it is labeled as a .nc file running ncvalidator on it tells us that it is actually an HDF5 file.

This does not seem right.

I am able to successfully run BSSP245 and BSSP585 successfully.

Sameer

 

[sacks]

Thank you for pointing this out, and I'm sorry that you ran into this issue. This file is in NetCDF4 format, which is the same as HDF5. We try to avoid having files in this format because, as you have found, they cannot be read by some NetCDF libraries. Specifically, you need to have a NetCDF library built with NetCDF4 support.

We have created a new version of this file in the older NetCDF3 format (ozone_strataero_WACCM_L70_zm5day_2015-2100_SSP126_c190221_netcdf3.nc). This file is identical to the original but with a file format that should work for you.

To use this version of the file, add the following to your user_nl_cam:
prescribed_ozone_file = 'ozone_strataero_WACCM_L70_zm5day_2015-2100_SSP126_c190221_netcdf3.nc'

 

[Sameer Agarwal]

Hi Bill,
Thank you for the prompt response and creating the new version of the file.

Adding that line to user_nl_cam caused cesm to download it but the run still crashed.

So the next thing I tried was to delete the netcdf4 version of the file, but when setting up the case and running it, it was downloaded again. So it seems cesm is still using it, despite the change in user_nl_cam.

What worked for me was to just replace the netcdf4 version of the file with the netcdf3 version of the file in the inputdata directory and then things worked without any changes to user_nl_cam.

Sameer

 

[sacks]

Okay, I'm glad you have that working. I guess that file is used in multiple places. Your solution seems reasonable.