To facilitate provenance within E3SM experiments and model intercomparisons, the following standards should be followed in all files output by E3SM components.
History global attributes
History files from E3SM components should all have these global attributes. Examples are from EAM and should be adjusted as appropriate.
These attributes are a mix of traditional CESM/CAM global attributes and CMIP global attributes. Many CMIP global attributes can only be added/defined during CMOR-ization. See https://docs.google.com/document/d/1h0r8RZr_f3-8egBMMh7aqLwy3snpD6_MrDz1q8n5XUk/edit
Anything labeled as “from coupler” can get its value from the infodata block in the coupler with a call to seq_infodata_GetData
Format below is: attribute name = value
title = (what is in this file) "EAM History file information" ;
source = (common full name for model) "E3SM Atmosphere Model" ;
source_id = (the git hash from coupler)
product = "model-output" ;
realm = see table in https://github.com/WCRP-CMIP/CMIP6_CVs/blob/master/CMIP6_realm.json
case = (CIME case id from coupler) ;
username = (username from coupler) ;
hostname = (hostname from coupler) ;
:git_version = (the git hash from coupler)
:history = (date-time stamp of file creation) "created on 05/02/21 23:58:09" ;
:Conventions = "CF-1.7" ;
:institution_id = "E3SM-Project" ;
:institution = "LLNL (Lawrence Livermore National Laboratory, Livermore, CA 94550, USA); ANL (Argonne National Laboratory, Argonne, IL 60439, USA); BNL (Brookhaven National Laboratory, Upton, NY 11973, USA); LANL (Los Alamos National Laboratory, Los Alamos, NM 87545, USA); LBNL (Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA); ORNL (Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA); PNNL (Pacific Northwest National Laboratory, Richland, WA 99352, USA); SNL (Sandia National Laboratories, Albuquerque, NM 87185, USA). Mailing address: LLNL Climate Program, c/o David C. Bader, Principal Investigator, L-103, 7000 East Avenue, Livermore, CA 94550, USA" ;
:contact = "e3sm-data-support@listserv.llnl.gov" ;
History variable attributes
Each variable in a history output file from an E3SM component should have the following attributes.
units = (CF-compliant unit if available. See https://cfconventions.org/Data/cf-standard-names/current/build/cf-standard-name-table.html. NOTE a unitless variable should either have no “units” attribute or the unit should be set to “1”)
long_name = (A long descriptive name which may, for example, be used for labeling plots. Use CMIP long name if available. See https://cmip6dr.github.io/Data_Request_Home/ )
standard_name = (CF-compliant standard name. Use only if units and sign match CF. See https://cfconventions.org/Data/cf-standard-names/current/build/cf-standard-name-table.html )
cell_methods = “time: mean” for time-averaged history.
cell_methods = “time: point” for instantaneous values. Other possibilities are in http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#appendix-cell-methods
Do not worry about spatial cell_method for a variable because CF only defines those for rectangular structured grids.