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NetCDF Climate and Forecast (CF) Metadata Conventions
Version 1.3, 7 November, 2008
Many others have contributed to the development of CF through their participation in discussions about proposed changes.
Abstract
This document describes the CF conventions for climate and forecast metadata designed to promote the processing and sharing of files created with the netCDF Application Programmer Interface [NetCDF]. The conventions define metadata that provide a definitive description of what the data in each variable represents, and of the spatial and temporal properties of the data. This enables users of data from different sources to decide which quantities are comparable, and facilitates building applications with powerful extraction, regridding, and display capabilities.
The CF conventions generalize and extend the COARDS conventions [COARDS]. The extensions include metadata that provides a precise definition of each variable via specification of a standard name, describes the vertical locations corresponding to dimensionless vertical coordinate values, and provides the spatial coordinates of non-rectilinear gridded data. Since climate and forecast data are often not simply representative of points in space/time, other extensions provide for the description of coordinate intervals, multidimensional cells and climatological time coordinates, and indicate how a data value is representative of an interval or cell. This standard also relaxes the COARDS constraints on dimension order and specifies methods for reducing the size of datasets.
Table of Contents
- Preface
- 1. Introduction
- 2. NetCDF Files and Components
- 3. Description of the Data
- 4. Coordinate Types
- 5. Coordinate Systems
- 5.1. Independent Latitude, Longitude, Vertical, and Time Axes
- 5.2. Two-Dimensional Latitude, Longitude, Coordinate Variables
- 5.3. Reduced Horizontal Grid
- 5.4. Timeseries of Station Data
- 5.5. Trajectories
- 5.6. Grid Mappings and ProjectionsHorizontal Coordinate Reference Systems, Grid Mappings, and Projections
- 5.7. Scalar Coordinate Variables
- 6. Labels and Alternative Coordinates
- 7. Data Representative of Cells
- 8. Reduction of Dataset Size
- A. Attributes
- B. Standard Name Table Format
- C. Standard Name Modifiers
- D. Dimensionless Vertical Coordinates
- E. Cell Methods
- F. Grid Mappings
- G. Revision History
- Bibliography
List of Tables
List of Examples
- 3.1. Use of
standard_name - 3.2. Instrument data
- 3.3. A flag variable, using
flag_values - 3.4. A flag variable, using
flag_masks - 3.5. A flag variable, using
flag_masksandflag_values - 4.1. Latitude axis
- 4.2. Longitude axis
- 4.3. Atmosphere sigma coordinate
- 4.4. Time axis
- 4.5. Perpetual time axis
- 4.6. Paleoclimate time axis
- 5.1. Independent coordinate variables
- 5.2. Two-dimensional coordinate variables
- 5.3. Reduced horizontal grid
- 5.4. Timeseries of station data
- 5.5. Trajectories
- 5.6. Rotated pole grid
- 5.7. Lambert conformal projection
- 5.8. Latitude and longitude on a spherical Earth
- 5.9. Latitude and longitude on the WGS 1984 datum
- 5.10. British National Grid
- 5.11. Multiple forecasts from a single analysis
- 6.1. Several parcel trajectories
- 6.2. Northward heat transport in Atlantic Ocean
- 6.3. Model level numbers
- 7.1. Cells on a latitude axis
- 7.2. Cells in a non-rectangular grid
- 7.3. Cell areas for a spherical geodesic grid
- 7.4. Methods applied to a timeseries
- 7.5. Surface air temperature variance
- 7.6. Climatological seasons
- 7.7. Decadal averages for January
- 7.8. Temperature for each hour of the average day
- 7.9. Temperature for each hour of the typical climatological day
- 7.10. Monthly-maximum daily precipitation totals
- 8.1. Horizontal compression of a three-dimensional array
- 8.2. Compression of a three-dimensional field
- B.1. A name table containing three entries
