NCEP/NCAR Reanalysis

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The reanalysis data are available for numerous meteorological parameters, as 6-hourly observations, and daily and monthly averages.  They generally extend back from the present day to 1948, and cover the entire globe.  For a full description of the project which sourced this data, you should visit the  NCEP/NCAR CDAS, Reanalysis Project Home Page.

The source data were provided by the NOAA-CIRES Climate Diagnostics Center, who provide a full description of the data. Please credit them if you use this data! Follow the 'description' link for details.

The work done at CRU has extracted spatial subsets of the data, and reformatted from netCDF to plain ASCII.  All enquiries about the validity of the data, or its development, should be addressed to the CDC or NCAR.

Generic Information about the NCEP/NCAR Reanalysis data files on this site

Only daily and 6-hourly data sets are referenced here, for a Quarter-Spherical window covering Eastern America and West/central Eurasia. Monthly data sets, and some alternative windows have been extracted, although they will be superceded by the new window. Email for details (see contact information at foot of page).

DAILY / 6-HOURLY FILES

• All files (apart from the land/sea masks) are gzipped.  Unzip with 'gunzip' (unix), 'winzip' (PC Windows), or 'macgzip' (Macintosh).
• Daily and 6-Hourly files are in ASCII text format, space-separated, with a field width of 12 characters.
• Each file contains vertically-concatenated grids of values, each grid being a set of values for a particular time step.
• Each line represents a latitude step; each column a longitude step.  The first line represents the northernmost latitude.
• The extraction window is 90°N - 0°N; 90°W - 90°E.  Since Surface Flux data are on Gaussian grids, the exact window sizes are sometimes non-integer.  Always see the appropriate Read_me file for exact details.
• The filename includes the dimensions of a single grid.
• An example filename, for air temperature, would be air.2m.gauss.1958.d.qs_eurasia.97x48.dat:

These datasets are made available under the Open Database License. Any rights in individual contents of the datasets are licensed under the Database Contents License under the conditions of Attribution and Share-Alike. Please use the attribution Climatic Research Unit, University of East Anglia