Links to the Global Atmospheric Reanalysis Datasets

(for monthly-mean data click)

ERA-Interim (click)
Period: January 1979 - present
Format: GRIB or netCDF
Note: Data can be downloaded from: (click; either "Full" or "Low" resolution)
Note: One time registration is necessary.
Note: ECMWF data FAQ answers many of your questions.
References: Dee et al. 2011


ERA-40 (click)
Period: September 1957 - August 2002
Format: GRIB or netCDF
Note: Data can be downloaded from: (click)
Note: One time registration is necessary.
Note: ECMWF data FAQ answers many of your questions.
References: Uppala et al. 2005


JRA-55 (click)
Period: January 1958 - present
Format: GRIB
Note: Registration (to get ID and password) is necessary to download data.
Note: Monthly data are now available (October 2013). JRA-55 data will be also available from other, non-JMA websites. See the release schedule at the JRA-55 website for further details.
References: Ebita et al. 2011


JRA-25/JCDAS (click)
Period: January 1979 - December 2013(?)
Format: GRIB (or 4-byte big_endian for Monthly Means)
Note: Registration (to get ID and password) is necessary to download data.
Note: The distribution of the JRA-25/JCDAS data (from the JMA site) will be terminated at the end of February 2014. But, JRA-25/JCDAS data will still be available through NCAR's Research Data Archive.
References: Onogi et al. 2007; see also Ebita et al. 2011


MERRA (click)
Period: January 1979 - present
Format: HDF or netCDF
Note: Data can be downloaded from: (click) (See "Data Access Methods" in this NASA page carefully; or, as an example, see "for monthly-mean data click" above)
Note: Longitude is from -180 through 0 to +180 degree, and latitude is from -90 through 0 to +90 degree.
Note: MERRA netCDF files do not contain the unit information. See File Specification documents for the unit and other detailed information.
References: Rienecker et al. 2011


NCEP CFSR (click)
Period: January 1979 - December 2009
Format: GRIB2
Note: Data can be downloaded from another website: (click)
References: Saha et al. 2010; Saha et al. 2010 supplement


NCEP/DOE AMIP-II (R2) (click)
Period: January 1979 - present
Format: netCDF
References: Kanamitsu et al. 2002


NCEP/NCAR (R1) (click)
Period: January 1948 - present
Format: netCDF
References: Kalnay et al. 1996; Kistler et al. 2001; see also references for R2 and CFSR


NOAA-CIRES 20CR (click)
Period: January 1871 - December 2010 (for Version 2) (1908-1958 for Version 1)
Format: netCDF
References: Compo et al. 2011



Information on the Reanalyses


Reanalyses.org:"Reanalysis Intercomparison and Observation" (click)
The reanalysis website prepared by the reanalysis centers.


NCAR's Research Data Archive (click)
NCAR's reanalysis data archive. Most reanalysis data (except for NASA-MERRA) can be found.
Note: You will create your own request at the site, and receive an email (maybe one day later or much sooner) to get the data files using a wget shell script file.
Note: Unfortunately, ECMWF data archived at this site cannot be distributed to scientists outside the USA, who need to go to the ECMWF's official website (see below).


NCAR/CGD's Data Catalog (click)
NCAR/CGD's Climate Analysis Section summarizes the reanalysis data information.


NCAR's Climate Data Guide (click)
An NCAR's website summarizes the reanalysis data information (click "Data").



Useful Tools


NCAR Command Language (NCL) (click)
ncl_convert2nc can convert various file types (including GRIB, GRIB2, and HDF) into netCDF. Note that the options "-nc4c -c 1" will give you a "nc4" file whose size is much smaller than a "nc" file; but, you need a higher version of netCDF to handle "nc4" files (see netCDF FAQ, Formats etc. for the details).

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