ESGF command line query¶
Four optional flags are available for the cmip5 and cmip6 commands to change the output or submit a data request:
clef --remote <dataset>returns all the ESGF datasets matching the constraints, it is the equivalent of doing a query online on an ESGF node
clef --local <dataset>finds local files accessing directly the NCI’s clef.nci.org.au database so it will also return older versions or datasets that might be temporarily offline.
clef --missing <dataset>finds files on ESGF that haven’t been downloaded to NCI
clef --request <dataset>create and pass to NCI a request to download the missing files
If these flags are omitted then the tool will look for the ESGF datasets matching the constraints and return both the local and missing files lists, based on querying an ESGF node.
The query works like the ESGF search website, e.g. https://esgf.nci.org.au/search/esgf_nci. Results can be filtered by using flags matching the ESGF query facets:
$ clef cmip5 --model ACCESS1.0 \ --experiment historical \ --frequency mon \ --variable ua \ --variable va
If the same flag is used multiple times both terms will be searched for.
Please note that CMIP5, CMIP6 and CORDEX have different query facets so different names and number of flags in CleF. We tried to use the same names wherever possible. In particular CMIP6 has some new flags available:
$ clef cmip6 --activity CMIP \ --experiment historical \ --source_type AOGCM \ --table Amon \ --grid gr \ --resolution "250 km" \ --variable ua \ --variable va `activity` - MIPS or sub-projects, for example CMIP refers to the DECK group of experiments `source_type` - model type, in the example above AOGCM is coupled Atmosphere-Ocean Global Climate Model `grid` - grid kind, in the example 'gr' stands for "regridded data reported on the data provider's preferred target grid" `resolution` - nominal resolution of the grid, there are two kind of nominal resolution. If the value is in degrees then this is a standard CMIP6 grid, currently only "1x1 degree" is available. If the resolution is in kms then this is an approximate resolution. Details are available in the appendix 2 of the CMIP6 attributes documentation: https://goo.gl/v1drZl Note that resolution is always composed of two separate words and will need to be passed as a string enclosed in quotes "".
While CORDEX has flags specifics to their experiment design:
domain - CORDEX region name rcm_name - Identifier of the CORDEX Regional Climate Model rcm_version - Identifier for reruns with perturbed parameters or smaller RCM release upgrades driving_model - Model/analysis used to drive the model (eg. ECMWFERAINT)
When querying the ESGF website, the total amount of results is limited to 10,000 files. If clef finds more results it will ask you to refine your query. You can follow the link to see the query clef used on the ESGF website:
$ clef cmip5 Exception: Too many results (1030069), try limiting your search https://esgf.nci.org.au/search/esgf_nci?query=&distrib=on&latest=on&project=CMIP5
clef --missing <dataset> queries the ESGF database for files that haven’t been downloaded to
NCI. It returns ESGF dataset IDs for each dataset that has one or more missing files:
$ clef --missing cmip5 --model HadCM3 --experiment historical \ --table day --ensemble r1i1p1 \ --variable ta Available on ESGF but not locally: cmip5.output2.MOHC.HadCM3.historical.day.atmos.day.r1i1p1.v20110728
- NOTE: ESGF keeps track of only the most recent versions of each file for a given dataset version,
- so if the files in the NCI mirror and ESGF don’t match this command can return false positives.
clef --local <dataset> queries the local file system for files that have been
downloaded to NCI. It returns the path to the file on NCI’s /g/data disk:
$ clef --local cmip5 --model HadCM3 --experiment historical --table day --ensemble r1i1p1 \ --variable ta --all-versions /g/data/al33/replicas/CMIP5/combined/MOHC/HadCM3/historical/day/atmos/day/r1i1p1/v20110728/ta /g/data/al33/replicas/CMIP5/combined/MOHC/HadCM3/historical/day/atmos/day/r1i1p1/v20140110/ta
NOTE: Presently the default behaviour for all the ESGF-node based queries is to check for the most recent (latest) version on ESGF, and return only files with that version. This can be disabled with the
The –local option instead currently returns by default all available versions, including versions unpublished by the ESGF but that are still available locally,
Most of the older CMIP5 collection (ua6 project) has been replaced by the new one (al33 project), this does not include older or superceded versions.
If your query does not return any results try again at a later time. The tool is querying the ESGF website first and sometimes one or more nodes can be disconnected and the returned results are incomplete. Try the –local flag to at least get what is available locally. For CMIP5 you can use the older ARCCSSive tool if in doubt.