#153: Requires related to specific standard names
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Reporter: martin.juckes | Owner: cf-conventions@…
Type: enhancement | Status: new
Priority: medium | Milestone:
Component: cf-conventions | Version:
Keywords: |
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This ticket is still under constrcution ......
A significant number of standard names contain, in their definitions,
explicit specifications for additional required metadata. For instance, if
the standard_name is "region" then there are constraints on the allowed
values of the data variable. The standard name descriptions cannot include
examples or markup, and the specification of the rules is not as clear as
in the convention text. It also appears that the rules are not checked by
the CF checker (at least not the few that I have looked at in detail) and
I think the best way to get consistent checking would be to first create a
well structured summary of these rules in the conventions document.
The specific proposal is add a new Appendix which lists the rules with
examples where appropriate.
= Appendix D: Rules associated with standard names =
Some standard names bring additional constraints on the meta-data and/or
data values of the variables they are associated with. This appendix list
such names, grouped according to the types of constraint, and provides
usage examples where needed.
The following table lists the rules and associated standard names. An
explanation of each rule follows below.
|||| =Rule= || =Standard Name(s)= ||
|| 1 || Area Fraction || area_fraction ||
|| 2 || Lifted from || atmosphere_convective_available_potential_energy,
atmosphere_convective_inhibition, atmosphere_level_of_free_convection,
atmosphere_lifting_condensation_level ||
|| 3 || Lifting range ||
temperature_difference_between_ambient_air_and_air_lifted_adiabatically ||
|| || to be completed || ||
== Area fraction ==
Variables with standard name area_fraction require a coordinate with
standard name area_type;
{{{
float cropcover(lat,lon);
standard_name: area_fraction;
coordinate: crop
character crop(nchar);
standard_name: area_type;
data:
crop: 'crop';
}}}
== Lifted from ==
atmosphere_lifting_condensation_level + 3 others: requires an
original_air_pressure_of_lifted_parcel coordinate.
== Lifting range ==
== Quantities representing a layer average or sum ==
Many "layer" quantities (e.g.
dry_static_energy_content_of_atmosphere_layer): require vertical
coordinate with bounds.
== Variation of variables in sigma coordinates due to surface pressure
change ==
change_in_energy_content_of_atmosphere_layer_due_to_change_in_sigma_coordinate_wrt_surface_pressure:
must have a vertical coordinate variable (axis=Z)
== Time rate of change or displacement over time ==
change_over_time_... and .._displacement: require bounds on time
coordinate
== Radiances ==
downwelling_photosynthetic_photon_radiance_in_sea_water and other radiance
variables: direction must be specified, e.g. with coordinate of
"zenith_angle".
== Variables which depend on reference air temperature and humidity ==
mass_concentration_of_pm..._ambient_aerosol_in_air (and
mass_fraction_of_pm..): require air_temperature and relative_humidity
== Functions of wavelength ==
isotropic_radiance_per_unit_wavelength_in_air (and other
per_unit_wavelength varables): the definition is slightly ambiguous with
the sentence "A coordinate variable for radiation wavelength should be
given the standard name radiation_wavelength" which, taken literally,
means the use of a wavelength coordinate is optional: should it be "A
coordinate variable for radiation wavelength should be given with the
standard name radiation_wavelength", making the wavelength coordinate
required?
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Ticket URL: <http://cf-trac.llnl.gov/trac/ticket/153>
CF Metadata <http://cf-convention.github.io/>
CF Metadata
