CMIP data

This page contains information on how data from the Coupled Model Intercomparison Project (CMIP) are stored in our NS9039K data structure in NIRD. This includes both CMIP5 and CMIP6 data, which have a slightly different structure.

We have endeavoured to keep the original structure of the CMIP data, but a small change has been made to the CMIP5 data structure in order to integrate it with our data storage structure.

CMIP6

Original structure

Information is avaiable about CMIP6 metadata here.

ESGF CMIP6 data follows the data structure:
<mip_era>/<activity_id>/<institution_id>/<source_id>/<experiment_id>/<variant_label>/<table_id>/<variable_id>/<grid_label>/<version>/
For example:
CMIP6/PAMIP/NCC/NorESM2-LM/pdSST-pdSIC/r46i1p1f1/Amon/psl/gn/v20190920/

NIRD structure

CMIP6 data is stored in NIRD under /projects/NS9039K/data/external/model/CMIP6. We use the same structure as the ESGF structure in our internal storage on NIRD.

Downloading CMIP6 data

Download here.

When downloading CMIP6 data from the ESGF node, if we do not have existing data in this activity, you will have to construct this directory structure yourself. All the information is available in the data search results, for example, in the first and third lines in Fig. 6.

Please do not modify the names of the CMIP6 data after downloading, the filenames also contain most of the metadata required to produce the data structure (except the MIP era, Activity ID, Institution ID and version).

Filenames take the form:
<variable_id>_<table_id>_<source_id>_<experiment_id>_<variant_label>_<grid_label>[<_temporal_subset>].nc
For example:
psl_Amon_NorESM2-LM_pdSST-pdSIC_r46i1p1f1_gn_200006-200105.nc

CMIP5

Original structure

Information is available about CMIP5 metadata here,

ESGF CMIP5 data follows the data structure:
<activity>/<product>/<institute>/<model>/<experiment>/<frequency>/<modeling realm>/<CMIP table/<variable name>/<ensemble member>/<version>
For example:
/CMIP5/output1/MOHC/HadDCM3/decadal1990/day/atmos/day/tas/r3i2p1/v20140110

Note that this differs a little from the above document, where the CMIP table (e.g. day or Omon) and version, is not required.

NIRD structure

CMIP5 data is stored in NIRD under /projects/NS9039K/data/external/model/CMIP5. Our structure is based on the ESGF structure but differs in that the <output> is divided into ‘PMIP’ and ‘CMIP’. ‘PMIP’ contains data from the Paleoclimate Modelling Intercomparison Project (the experiments ‘past1000’, ‘lgm’ and ‘midHolocene’), and ‘CMIP’ contains all other CMIP5 data. The rest of the structure remains the same.

Downloading CMIP5 data

Download here.

When downloading CMIP6 data from the ESGF node, if we do not have existing data in this activity, you will have to construct this directory structure yourself. All the information is available in the data search results, for example, in the ‘id’ at the bottom of Fig. 7.

Please do not modify the names of the CMIP5 data after downloading.

Processing CMIP data

If you would like to compress the CMIP data, you can do this and leave it in the original data structure. For other processing tasks such as regridding, or generation of new composite variables, please save the output of such processing in a ‘derived’ directory. This should be in the location: /projects/NS9039K/data/external/model/<mip_era>/<activity_id>/<derived>/<ui_d>/ where <ui_d> is a directory with your user initials followed by a brief description. For example, there is a derived dataset in the following location: /projects/NS9093K/data/external/model/CMIP6/PMIP/derived/lb_1.5x1.5/ which corresponds to CMIP6 data regridded to a regular 1.5 degree grid.