WARNING
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
- The output files are written through the NetCDF API
- The NETCDF4 _CLASSIC model will be adopted
- Recommended compression level deflate=6
- Shuffling=True
- Fletcher32=True is strongly recommended
File Structure
- 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
Create hash filessha256sum filename.nc > filename.sha256
File Naming
NEW PROPOSAL (20170419):
<institute>_<model_id tag>_<modeling realm>_<frequency>_<level>_<start date identifier>_<data year><data month><data day><data hour>[-<data year><data month><data day><data hour>]_<variable name>_<ensemble member>.nc |
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OLD PROPOSAL:
<institute>_<stream>_<modeling realm>_<frequency>_<level>_<production date and start date identifier>_<data year><data month><data day>[-<data year><data month><data day>]_<variable MARS name>_<ensemble member> examples: egrr_enfh_atmos_day_sfc_201601A_19950417-19950418_ta_r3.nc "201601A" is a placeholder while a form for representing the model version, production year and startdate is determined: e.g. could the filename (alternatively) be something like: e |
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Metadata
- 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