SPARC Reanalysis Intercomparison Project

Links to Global Atmospheric Reanalysis Datasets

ERA5

Data Access:ECMWF
Period:2010–2016 (as of July 2017; 1950–present in 2019)
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:General information on ERA5, including the public release plan, is available at the Copernicus site
References: See the Copernicus site for the time being

CERA-20C (ECMWF 10-member ensemble of coupled climate reanalyses of the 20th century, which assimilates only surface pressure and marine wind observations as well as ocean temperature and salinity profiles.)

Data Access:ECMWF: 3-hourly (monthly mean etc. also available)
Period:January 1901–December 2010
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:General information on CERA-20C is available here
References: See this site for the time being

ERA-20C (ERA-CLIM pilot reanalysis of the 20th-century using surface observations only)

Data Access:ECMWF: 3-hourly (monthly mean etc. also available) || NCAR RDA: 3-hourly
Period:January 1900–December 2010
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:General information on ERA-20C is available here
References:Poli et al., 2016

ERA-20CM (Model integration with specified conditions, using the same forecast model used for ERA-20C)

Data Access:ECMWF: 3-hourly (monthly mean etc. also available)
Period:January 1899–December 2010
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:General information on ERA-20CM is available here
References: Hersbach et al., 2015

ERA-Interim

Data Access:ECMWF: 6-hourlyMonthly || NCAR RDA: 6-hourlyMonthly
Period:January 1979–present
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:For ERA-Interim grid, see ERA-Interim Horizontal Coordinate Conventions and Numerical Attributes by David Stepaniak (NCAR/CISL Data Support Section)
Note:Users of Python, Perl, or Java can also access the ECMWF data servers in batch.
References:Dee et al., 2011

ERA-40

Data Access:ECMWF: 6-hourlyMonthly || NCAR RDA: 6-hourlyMonthly || RISH
Period:September 1957–August 2002
Format:GRIB or netCDF
Note:Registration is necessary to download data
Note:Users of Python, Perl, or Java can also access the ECMWF data servers in batch.
Additional Data:NCAR ERA-40 Data Listing (includes analysis and forecasts on various grids, as well as tendency terms)
References:Uppala et al., 2005

JRA-55

Data Access:JMA || NCAR RDA: 6/3-hourlyMonthly || DIAS || RISH
Period:January 1958–present
Format:GRIB
Note:Registration is necessary to download data
References:Kobayashi et al., 2015; Harada et al., 2016

JRA-55C (conventional data only)

Data Access: NCAR RDA: 6/3-hourlyMonthly || DIAS
Period:November 1972–December 2012
Format:GRIB
Note:Registration is necessary to download data
References:Kobayashi et al., 2014

JRA-55AMIP (no observational data assimilated)

Data Access: NCAR RDA: 6/3-hourly || DIAS
Period:January 1958–January 2013
Format:GRIB
Note:Registration is necessary to download data
References:Kobayashi et al., 2014

JRA-25/JCDAS

Data Access: NCAR RDA: 6-hourlyMonthly
Period:January 1979–January 2014
Format:GRIB (or 4-byte big_endian for monthly means)
Note:Registration is necessary to download data
Note:JMA terminated distribution of JRA-25/JCDAS at the end of February 2014. The data remain available through NCAR.
Note (15 Aug 2017):It has been found that the profiles in the fcst_phy3m25 files are shifted slightly downward incorrectly. This is due to the use of half-level coefficients (instead of the full-level coefficients) when the conversion from fcst_phy3m to fcst_phy3m25 was made at JMA. All other files such as fcst_phy3m, anl_p, anl_p25, etc. are OK. Contact Masatomo Fujiwara for more information.
References:Onogi et al., 2007 (see also Ebita et al., 2011)

MERRA-2

Data Access: GES DISC | FTP site | MDISC (subsetter)
Period:1980–present
Format:netCDF4
Note:For MERRA and MERRA-2, there are two types of data product, (1) IAU state (or 'ASM', or 'asm', or 'Assimilation' in the file header/name) and (2) analyzed state (or 'ANA', or 'ana', or 'analysis', or 'DAS'). The explanation of them is found in Rienecker et al. (2011) and Gelaro et al. (2017); see also 3rd paragraph of page 1431 of Fujiwara et al. (2017). Except for very special cases, data users should choose '(1) IAU state' product.
Note:The MERRA-2 file specifications can be found here
Note:For MERRA-2, each data collection has a DOI number that should be cited (*see the next Note) when the data are used. The DOI numbers are included in the data files and the complete list is summarized in the MERRA-2 file spec document (Bosilovich et al. (2015) GMAO Office Note No. 9) - see pages 58-61, Table 6.1.
*Note: See, for example, Manney et al. (2017) how to cite MERRA-2 data in the References section of your paper.
References: Gelaro et al., 2017

MERRA

Data Access:NASA (multiple products available for subset and download; see product information pages for details)
Period:1 January 1979 – 29 February 2016
Format:HDF or netCDF
Note:For MERRA and MERRA-2, there are two types of data product, (1) IAU state (or 'ASM', or 'asm', or 'Assimilation' in the file header/name) and (2) analyzed state (or 'ANA', or 'ana', or 'analysis', or 'DAS'). The explanation of them is found in Rienecker et al. (2011) and Gelaro et al. (2017); see also 3rd paragraph of page 1431 of Fujiwara et al. (2017). Except for very special cases, data users should choose '(1) IAU state' product. It should be noted, however, that MERRA's IAU product is provided at a reduced horizontal resolution and only on pressure levels (not model levels).
Note:Product introduction and tools are available from the NASA Global Modeling and Assimilation Office
Note:MERRA netCDF files may not contain unit information; see the file specification documents for units and other details
References:Rienecker et al., 2011

CFSR

Data Access (1) "CDAS-T382": NOAA: 6-hourlyMonthly (Jan. 1979-Mar. 2011; see NOAA CFS's site; see also NCAR RDA and notes below) || NCAR RDA: 6-hourlyMonthly (Jan. 1979-Dec. 2010)
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Data Access (2) "CFSv2" or "CDAS-T574": NCAR RDA: 6-hourlyMonthly (Jan. 2011 – present)
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Data Access (3) Model level data: NOAA ftp site (1979-2015; to be extended) (contact Sean Davis for access information; see Butler et al. (2017 AMS Mid. Atmos. Conf., poster pdf) for overview of this data set.)
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Period:January 1979–December 2009, January 2010–December 2010, January 2011–March 2011, April 2011–present (see notes below)
Format:GRIB2
Note:Registration is necessary to download data from the NCAR RDA
Note:See NCAR RDA's FAQ and file name conventions pages for 6 hourly and for Monthly (for example, choose "pgbhnl" files for analysis at 0.5°×0.5° and "pgblnl" files for analysis at 2.5°×2.5°)
Note: Official data coverage by CFSR only extends through December 2009, but output from the same analysis system was continued through December 2010 before being migrated to the operational CFSv2 analysis system from January 2011. This transition from CFSR to CFSv2 should not be confused with the transfer of CFSv2 production from NCEP EMC to NCEP operations, which occurred at the start of April 2011. CFSv2 has a different horizontal resolution and includes minor changes to physical parametrizations, but is intended to serve as a continuation of CFSR and can be treated as such for most purposes. To distinguish CFSR and its CFSv2 continuation from other (mainly forecast) applications of the NCEP CFS that do not use the full data assimilation system, CFSR may also be referred to as CDAS-T382 and its continuation as CDAS-T574. (See Section 2.4 of Fujiwara et al., 2017.)
References:Saha et al., 2010 (see also supplementary materials); for the CFSv2, see Saha et al., 2014.

NCEP–DOE Reanalysis 2

Data Access:NOAA ESRL || NCAR RDA 6 hourlyMonthly || RISH
Period:January 1979–present
Format:GRIB or netCDF
Note:Registration is necessary to download data from the NCAR RDA
References:Kanamitsu et al., 2002

NCEP–NCAR Reanalysis 1

Data Access:NOAA ESRL || NCAR RDA: 6-hourlyMonthly || RISH
Period:January 1948–present
Format:GRIB or netCDF
Note:Registration is necessary to download data from the NCAR RDA
References:Kalnay et al., 2002; Kistler et al., 2001 (see also references for R2 and CFSR)

NOAA–CIRES 20th Century Reanalysis (20CR)

Versions, Period:Ver. 1: January 1908–December 1958; Ver. 2: November 1869–December 2012; Ver. 2c: 1851–2011
Data Access: Overview || NOAA ESRL: Ver. 2Ver. 2c || NCAR RDA: Ver. 1Ver. 2Ver. 2c || NERSC: 20CR Ensemble Gateway (full fields for Ver. 2, Ver. 2c)
Format:GRIB or netCDF
Note:Registration is necessary to download data from the NCAR RDA
Note:See also data information and plotting tools at the NOAA ESRL Physical Sciences Division website.
References:Compo et al., 2011