Annexe: Some Data Request vocabulary

In the Data Request world, there are different collections used to describe and refer to variables. It is useful to have their definition in mind.

MIP Variable

A MIP Variable (‘MIPvar’) defines a variable name and refers to the corresponding CF-standard name when that standard exists. There is no notion of frequency nor spatial or temporal dimensions for a MIP Variable.

A MIP variable is defined by the following attributes (for the exhaustive list of attributes see for example, http://clipcservices.ceda.ac.uk/dreq/u/0e5d376315a376cd2b1e37f440fe43d3.html ):

  • A label (e.g.: label=’tos’);

  • A title (e.g.: title=’Sea Surface Temperature’);

  • (possibly) A CF standard name (e.g: standarname=’SeaSurfaceTemperature’);

  • Units (e.g.: units=‘K’).

Note that several MIP variables can refer the same CF standard name, e.g. the following MIP variables all refer to the CF standard name ‘SurfaceAlbedo’:

  • al: Albedo [%]

  • alb: Surface Albedo

  • albsrfc: surface albedo

  • fal: Forecast Albedo

  • lialb: Land ice or snow albedo

  • lialbIs: Ice Sheet Ice or Snow Albedo

  • surf-albedo: surface_albedo

CMOR Variable

A CMOR Variable (‘CMORvar’) is a declination of a MIP variable, associated to a realm and to a MIP table with a particular output frequency and spatial/temporal structure.

A CMOR Variable is defined by the following attributes (for the exhaustive list of attributes see for example, http://clipc-services.ceda.ac.uk/dreq/u/baa52de0-e5dd-11e5-8482-ac72891c3257.html)

  • a variable identifier (e.g: vid=’0e5d376315a376cd2b1e37f440fe43d3’) that links to the base MIP Variable;

  • a label (e.g.: label=’tos’ );

  • a title (eg: title=’Sea Surface Temperature’ );

  • a sampling frequency (e.g.: frequency=’mon’ );

  • a modelling realm (e.g.: realm=’atmos’ );

  • a mipTable (e.g.: table=’Omon’ );

  • a structure identifier (e.g.: stid=’f7ddef0c-562c-11e6-a2a4-ac72891c3257’ ) that gather both temporal and spatial shapes information

  • a default priority ( DefaultPriority =1)

Note that the label of the CMOR Variable may differ from the label associated MIP Variable (e.g.: ‘hus10’ and ‘hus27’ – specific humidity on different sets of pressure levels- are CMOR Variables referring to the same MIP Variable ‘hus’ )