Facets

A facet is a key-value pair that describes a certain property of a dataset and enables faceted search, for example as provided by ESGF. The facets used on ESGF are closely related to the global attributes defined by the controlled vocubulary used by the various “project”s hosted on ESGF. A “project” is a collection of datasets that share certain properties, e.g. CMIP7 is a project. Each project has its own set of facets that are relevant for that project. The documents linked below provide an overview of the official facets for various projects. They also provide a reference directory structure and file naming convention based on facets, which is used to organise data on local filesystems.

ESMValCore uses “facets” to search for and define input data, both in the recipe and in the esmvalcore.dataset.Dataset object. This allows specifying data without relying on e.g. file names or directory structures, which may vary between computers. ESMValCore uses its own set of facets, which is consistent across all projects it supports.

Here is a mapping from the facet names used in ESMValCore to the corresponding project specific facet names used on ESGF.

CMIP7

Official CMIP7 facets.

Note

This mapping is prelimary as no CMIP7 data bas been published on ESGF yet.

ESMValCore facet	ESGF facet
activity	activity_id
branding_suffix	branding_suffix
dataset	source_id
ensemble	variant_label
exp	experiment_id
frequency	frequency
grid	grid_label
institute	institution_id
realm	realm
region	region
project	project / mip_era
short_name	variable_id
version	version

CMIP6

Official CMIP6 facets.

ESMValCore facet	ESGF facet
activity	activity_id
dataset	source_id
ensemble	member_id
exp	experiment_id
frequency	frequency
grid	grid_label
institute	institution_id
mip	table_id
realm	realm
project	project / mip_era
short_name	variable_id

CMIP5

Official CMIP5 facets. Note that there appear to be differences between the official facets and those used on ESGF. Below we present the facets used on ESGF.

ESMValCore facet	ESGF facet
dataset	model
ensemble	ensemble
exp	experiment
frequency	time_frequency
institute	institute
mip	cmor_table
realm	realm
product	product
project	project
short_name	variable

CMIP3

ESMValCore facet	ESGF facet
dataset	model
ensemble	ensemble
exp	experiment
frequency	time_frequency
short_name	variable

CORDEX

Official CORDEX-CMIP5 facets. Note that there appear to be differences between the official facets and those used on ESGF. Below we present the facets used on ESGF.

ESMValCore facet	ESGF facet
dataset	rcm_name
driver	driving_model
domain	domain
ensemble	ensemble
exp	experiment
frequency	time_frequency
institute	institute
short_name	variable

obs4MIPs

Official obs4MIPs facets. Note that obs4MIPs first followed the CMIP5 conventions before switching to the CMIP6 conventions. That means that both conventions are in use depending on when a particular dataset was published. See the CMIP5 and CMIP6 tables above for the mappings.