Metadata key reference

This page lists all high-level (format independent) metadata keys that can be accessed via get() and used in sel() and order_by().

Keys follow the "<component>.<name>" naming convention. Each section below corresponds to one component; click the component heading to go to its dedicated page.

Parameter

Key	Description
parameter.variable	Parameter variable name as a string (e.g. "2t"). Not normalised; taken directly from the source data.
parameter.param	Alias of parameter.variable.
parameter.standard_name	CF standard name of the parameter variable.
parameter.long_name	CF long name of the parameter variable.
parameter.units	Units of the parameter as a Units object.
parameter.chem	Chemical constituent or aerosol type, or None for non-chemical parameters.
parameter.chem_long_name	Long name of the chemical constituent or aerosol type, or None.
parameter.wavelength	Central wavelength for optical parameters, or None. Accepts an optional units argument for conversion.
parameter.wavelength_bounds	Wavelength bounds as a 2-tuple for optical parameters, or None.
parameter.wavelength_units	Units of the wavelength (e.g. nanometres), or None.
parameter.wave_direction	Wave propagation direction for 2-D wave spectra parameters, or None.
parameter.wave_direction_index	0-based index of the wave direction bin, or None.
parameter.wave_direction_bounds	Direction bounds as a 2-tuple, or None.
parameter.wave_direction_units	Units of the wave direction (e.g. degrees), or None.
parameter.wave_frequency	Wave frequency for 2-D wave spectra parameters, or None.
parameter.wave_frequency_index	0-based index of the wave frequency bin, or None.
parameter.wave_frequency_bounds	Frequency bounds as a 2-tuple, or None.
parameter.wave_frequency_units	Units of the wave frequency (e.g. 1/s), or None.

Time

Key	Description
time.base_datetime	The base (reference) datetime of the forecast as a datetime.datetime.
time.forecast_reference_time	Alias of time.base_datetime.
time.base_date	The date part of the base datetime as a datetime.date.
time.base_time	The time-of-day part of the base datetime as a datetime.time.
time.valid_datetime	The valid datetime (base_datetime + step) as a datetime.datetime.
time.step	The forecast step as a datetime.timedelta. Integer values are interpreted as hours.
time.forecast_period	Alias of time.step.
time.forecast_month	The forecast month as an integer. Only available for monthly forecast time; returns None otherwise.
time.indexing_datetime	The indexing datetime used for ordering within a dataset. Returns None for types that do not define it.

Vertical

Key	Description
vertical.level	Scalar level value in the native units of the level type.
vertical.level_type	Level type name as a string (e.g. "pressure").
vertical.layer	Layer bounds as a (bottom, top) tuple, or None for non-layer types.
vertical.abbreviation	Abbreviation of the level type (e.g. "pl").
vertical.units	Units of the level value.
vertical.positive	Positive direction of the coordinate ("up", "down", or None).
vertical.cf	Dictionary of CF metadata (standard_name, long_name, units, positive).
vertical.parametric	True if the level type is parametric (e.g. hybrid levels).
vertical.coefficients	Coefficient arrays for parametric level types, None otherwise.
vertical.coefficient_names	Names of the coefficients for parametric level types, None otherwise.
vertical.number_of_levels	Number of model levels for parametric level types, None otherwise.

Geography

Key	Description
geography.latitudes	Array of latitude values for every grid point. dtype argument supported for type control.
geography.longitudes	Array of longitude values for every grid point. dtype argument supported for type control.
geography.distinct_latitudes	1-D array of unique latitude values for regular grids, or None for irregular grids.
geography.distinct_longitudes	1-D array of unique longitude values for regular grids, or None for irregular grids.
geography.x	Array of x-coordinates in the native CRS. dtype argument supported.
geography.y	Array of y-coordinates in the native CRS. dtype argument supported.
geography.shape	Grid shape as a tuple of integers (e.g. (latitude_size, longitude_size) for a 2-D lat/lon grid).
geography.projection	Projection object describing the CRS, or None.
geography.bounding_box	BoundingBox for the grid extent.
geography.area	Bounding box as a (north, west, south, east) tuple of floats.
geography.grid_type	String identifying the grid type (e.g. "regular_ll", "reduced_gg").
geography.grid_spec	Grid specification. Can be used to construct a new geography of the same type. Experimental; may not be available for all geography types.
geography.grid	eckit.geo.Grid object. Experimental; may not be available for all geography types.
geography.unique_grid_id	A hashable identifier that is the same for two fields sharing an identical grid.

Ensemble

Key	Description
ensemble.member	Ensemble member identifier as a string, or None for deterministic data.
ensemble.realization	Alias of ensemble.member.
ensemble.realisation	Alias of ensemble.member.

Processing (proc)

Warning

This component is experimental and may be changed in future versions of earthkit-data.

Key	Description
proc.time	The first TimeProcItem in the processing list, or None if no time processing is present.
proc.time_value	The time-span value from the first time processing item as a datetime.timedelta, or None.
proc.time_method	The processing method from the first time processing item as a TimeMethod, or None.

Labels

Labels use "labels.<user_key>" where user_key is any string chosen by the caller. There are no predefined keys; every key-value pair is user-supplied.

>>> field.get("labels.my_key")
>>> field.set({"labels.my_key": "value"})

See Labels component for the full API and usage examples.