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This is still a work in progress...

Text in black can be considered well-established, but text in orange is still under discussion

File formatting

Each netCDF4 file contains a single output variable (along with coordinate/grid variables, attributes and other metadata) from a single model and a single simulation (i.e., from a single ensemble member and a single start date)
There is flexibility in specifying how many time slices (samples) are stored in a single file. A single file can contain all the time-samples for a given variable and climate experiment, or the samples can be distributed in a sequence of files.
Recommended maximum file size of 4GB
A file containing a hash created with sha256sum should be created for each file
sha256sum filename.nc > filename.sha256

examples:

egrr_enfh_atmos_day_sfc_201601A_19950417-19950418_ta_r3.nc

egrr_enfh_atmos_month_plev_201601A_199504-199505_ta_r3.nc

"201601A" is a placeholder while a form for representing the model version, production year and startdate is determined:

egrr_enfh_atmos_month_plev_P2016_M1A_S19950401_199504-199505_ta_r3.nc

P=production year

M=model version

S=startdate

e.g. could the filename (alternatively) be something like:

egrr_enfh_atmos_month_plev_S19950401_199504-199505_ta_r3p20160101m411.nc

Much of the metadata written to the output files is defined in MIP-specific tables of information, which in this document are referred to simply as "MIP tables" in ASCII files.
The metadata is constrained by the CF convention (NetCDF Climate and Forecast (CF) Metadata Convention)
This is also based on information from the SPECS_standard_output.pdf document, the CMIP5 tables and the Attribute Convention for Data Discovery.
- Attributes currently are a significantly reduced subset of the SPECS/CMIP5 requirements with minor adaptations