CMIP6 Data

The World Climate Research Programme (WCRP) Working Group on Coupled Modelling ( WGCM) oversees the Coupled Model Intercomparison Project Phase 6 (CMIP6). This is an ongoing project which combines climate modelling experiments and produces huge quantities of data archived around the world by members of the Earth System Grid Federation (ESGF). CMIP6 performed during the years 2019 - present and will inform the IPCC Sixth Assessment Report (AR6).

NOTE -  This project is in progress and data are still being actively retrieved by CEDA, not all datasets are complete. At present, data can not be found through the CEDA catalogue. Information about other climate datasets on the CEDA Archive (including CMIP5) can be found here

Data Access (CEDA)

Data can be obtained from the CEDA data browser:  

Alternatively, data can be obtained directly from JASMIN under:

 /badc/cmip6/data/

If you can't find the data you need, you can see if the data are available from the full CMIP distributed archive searchable via the ESGF (see the section below).

The following will describe the directory structure and filename composition of the CMIP6 data so users can find specific data more easily:

Directory

The directory structure for CMIP6 is as follows:

<mip_era>/<activity_id>/<institution_id>/<source_id>/<experiment_id>/<variant_label>/<table_id>/<variable_id>/<grid_label>/<version>
  • mip_era: refers to the phase of the project, this will be CMIP6
  • activity_id: is the abbreviated identifier of the project or experiments run. For example; Aerosols and Chemistry Model Intercomparison Project (AerChemMIP), Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP) or Scenario Model Intercomparison Project (ScenarioMIP). A full list can be found here
  • institution_id: refers to the centre or institute responsible for the model
  • source_id:  is the model used. Details for all should eventually be shown on ES-DOC, this is an ongoing process
  • experiment_id: refers to the set experiments being run for CMIP6. For example; PiControl, historical and 1pctCO2 (1 percent per year increase in CO2)
  • variant_label: is a label constructed from 4 indices (ensemble identifiers) r<k>i<l>p<m>f<n> where:
    • k = realization_index
    • l = initialization_index
    • m = physics_index
    • n = forcing_index
  • table_id: this refers to the MIP table being used. The MIP tables are used to organise the variables. For example, Amon refers to monthly atmospheric variables and Oday contains daily ocean data. Each variable in a MIP table must have a unique output name. To understand more about the naming conventions of MIP tables please see here
  • variable_id: is the data variable (e.g. Near-Surface Air Temperature (tas), Surface Air Pressure (ps), Relative Humidity (hur))
  • grid_label: this describes the model grid used. For example; global mean data (gm), data reported on a model's native grid (gn) or regridded data reported on a grid other than the native grid and other than the preferred target grid (gr1)
  • version: refers to the data version (date)

Filenames

<variable_id>_<table_id>_<source_id>_<experiment_id>_<member_id>_<grid_label>_<time_range>.nc
  • variable_id: is the data variable (e.g. Near-Surface Air Temperature (tas), Surface Air Pressure (ps), Relative Humidity (hur))
  • table_id: this refers to the MIP table being used. The MIP tables are used to organise the variables. For example, Amon refers to monthly atmospheric variables and Oday contains daily ocean data. Each variable in a MIP table must have a unique output name. To understand more about the naming conventions of MIP tables please see here
  • source_id:  is the model used. Details for all should eventually be shown on ES-DOC, this is an ongoing process
  • experiment_id: refers to the set experiments being run for CMIP6. For example; PiControl, historical and 1pctCO2 (1 percent per year increase in CO2)
  • member_id: is a label constructed from 4 indices (ensemble identifiers) r<k>i<l>p<m>f<n> where:
    • k = realization_index
    • l = initialization_index
    • m = physics_index
    • n = forcing_index
  • grid_label: this describes the model grid used. For example; global mean data (gm), data reported on a model's native grid (gn) or regridded data reported on a grid other than the native grid and other than the preferred target grid (gr1)
  • time_range: the date range of the data file in the format YYYMM

Data Access (ESGF)

To search through all CMIP6 data please visit the ESGF site. From this site, you can download the data that you require and analyse it through JASMIN by copying it to your group workspace (this should only be done with small numbers of data files to avoid consuming all of your gws quota).

The ESGF site allows you to search through all the available CMIP6 data by filtering with specific requirements. These filters mimic the directory structure used to store data in the CEDA Archive (as seen in the section above).

To access the NetCDF files, select 'list files' and from here the file can be downloaded via http or openDAP. Other methods of downloading the files are available including THREDDS catalog or by using a wget script.

Acronyms

Below are some acronyms associated with CMIP:

AMIP Atmosphere Model Inter-Comparison project
CDS Climate Data Store 
CMIP Coupled Model Intercomparison Project
ES-DOC Earth System Documentation
ESGF Earth System Grid Federation
IPCC Intergovernmental Panel on Climate Change
PiControl Pre-Industrial Control
WCRP World Climate Research Programme

Still need help? Contact Us Contact Us