NCAR RDA supported ERA5, ECMWF operational, and future reanalysis products to be provided in NetCDF format

The Research Data Archive at NCAR plans to restructure and translate future reanalysis products, selected operational NWP products, and selected in-situ observational data products into CF-compliant NetCDF from the native NWP formats moving forward.  This action is being taken for a variety of reasons as described below.

NetCDF provides:

• Support for more effective and emerging data compression options (30% less storage volume currently needed for ERA5 in NetCDF vs GRIB1 and GRIB2 formats).
• Capability to follow best practices for long term data curation by storing data in a self describing format (no need for external tables, sometimes unique to each data provider).
• Capability to include provenance tracking within the data files (Dataset Digital Object Identifier (DOI) along with a description of data preparation workflow steps are included global attributes for ERA5).
• A broader set of community supported data analysis tools.
• Support for object store (cloud) access in the underlying NetCDF/HDF libraries and community supported capabilities to translate from NetCDF to cloud optimized data analysis formats.

Additionally, restructuring and translating the data from native GRIB
formats to CF-compliant NetCDF solves interoperability issues
created by non-standard GRIB1 and GRIB2 encoding practices used by NWP centers to serve their internal use case needs.

For WRF users: Community efforts are underway to develop tools to translate NetCDF data into WRF-intermediate format.  Currently ungrib is the only tool provided to do this in the WRF preprocessing system (WPS) software package.  Some WRF users have developed their own tools and workflows to translate data from NetCDF into the WRF-intermediate format.