CEDA: CF Conventions - examples of global attributes
The CF conventions are guidelines and recommendations as to where to put information, and they provide advice as to what information you might want to include in your (NetCDF) file. Extra attributes are not outlawed and CEDA strongly recommends that you include as much information as possible.
CF conventions make one global attribute mandatory: Conventions "CF-1.0"
For the source, if the data are model generated, source should name the model and the version number. If the data are observational, source should characterise them, e.g. surface observation, radiosonde, satellite.
With the history attribute, well-behaved generic software will automatically append its name, input parameters, and a timestamp.
Here we give three examples of datasets using the CF conventions, with the recommended global attributes:
Instrumental Data
| Global attributes | Succinct definition | Instrumental data example |
|---|---|---|
| Conventions | "CF-1.0"; | |
| title | A succinct description of what is in the dataset. | "Chilbolton 3-GHz Advanced Meteorological Radar: Doppler Radar"; |
| institution | Specifies where the original data were produced. | "Original data recorded at Chilbolton Observatory (BN_Grid_Ref=\"SU 394 386\"), part of the Radio Communications Research Unit, RAL, UK.\n" "Data processed at University of Reading.\n" "Data held at the Centre for Environmental Data Analysis (CEDA),UK."; |
| source | The method of production of the original data. | "Chilbolton 3-GHz Advanced Meteorological Radar (CAMRa)\n" "Frequency: 3.075 GHz\n" "Antenna diameter: 25m\n" "Peak power: 560 kW\n" "Pulse width: 0.5 us\n" "Pulse repetition frequency: 610Hz\n" "Beam width: 0.28 degrees\n" "Cross-polar isolation: -34 dB"; |
| history | Provides an audit trail for modifications to the original data. | "16/08/02 10:47:54 - netCDF generated from original data using softare version 1.1.7 by " user" "data file "\n" "16/08/02 10:47:55 - unfolded data using chilunfold -noisyPHIDP" -user " user" "data file""; |
| references | Published or web-based references which describe the data, or the methods used to produce them. | "Information on the data is available at https://artefacts.ceda.ac.uk/badc_datadocs/chilbolton%5cn" "Further information on the data is available at http://www.met.rdg.ac.uk/radar/doc/camra.html"; |
| comment | Miscellaneous information about the data or the methods used to produce them. | "In calculating the height of each data point, the curvature of the earth should be accounted for.\n" "Data restrictions: for academic research use only."; |
Gridded Model Data
| Global attributes | Succinct definition | Gridded model data example |
|---|---|---|
| Conventions | "CF-1.0"; | |
| title | A succinct description of what is in the dataset. | "ECMWF ERA-40 Re-analysis data: Model Level Parameters"; |
| institution | Specifies where the original data were produced. | "Data owned by ECMWF.\n" "Data held by the Centre for Environmental Data Analysis (CEDA),UK"; |
| source | The method of production of the original data. | "Data generated by the European Centre for Medium-Range Weather Forecasts (ECMWF) T159L60 version of the Integrated Forecast System ERA-40 model."; |
| history | Provides an audit trail for modifications to the original data. | "07/08/01 - Data originally extracted from the ECMWF MARS archive.\n" "21/03/02 - Conversion from GRIB to netCDF format at CEDA using XCONV V1.05"; |
| references | Published or web-based references which describe the data, or the methods used to produce them. | "Information on the data is available at http://archive.ceda.ac.uk/ecmwf-e40%5cn" "Further information is available from the ECMWF web pages at https://www.ecmwf.int/research/era/Project/index.htm"; |
| comment | Miscellaneous information about the data or the methods used to produce them. | "Data restrictions: for academic research use only."; |
Surface Data
| Global attributes | Succinct definition | Surface station data example |
|---|---|---|
| Conventions | "CF-1.0"; | |
| title | A succinct description of what is in the dataset. | "UK Met Office Surface data: Rainfall Amount"; |
| institution | Specifies where the original data were produced. | "Data owned by UK Met Office.\n" "Data held by the Centre for Environmental Data Analysis (CEDA),UK."; |
| source | The method of production of the original data. | "UK Met Office surface station data\n" "MET_DOM: WADRAIN\n" "STATION_ID: 261316"; |
| history | Provides an audit trail for modifications to the original data. | "Data collected on day of measurement.\n" "30/11/97 - Stored in Met Office MIDAS database.\n" "12/05/00 - Extracted from MIDAS by CEDA."; |
| references | Published or web-based references which describe the data, or the methods used to produce them. | "Information on the data is available at https://artefacts.ceda.ac.uk/badc_datadocs/surface/"; |
| comment | Miscellaneous information about the data or the methods used to produce them. | "Data restrictions: for academic research use only."; |