NOAA/CIRES Twentieth Century Global Reanalysis Version 2c 

    The Twentieth Century Reanalysis Project, produced by the Earth System Research Laboratory Physical Sciences Division from NOAA and the University of Colorado Cooperative Institute for Research in Environmental Sciences, is an effort to produce a global reanalysis dataset spanning a portion of the nineteenth century and the entire twentieth century (1851 - near present), assimilating only surface observations of synoptic pressure. Boundary conditions of pentad sea surface temperature and monthly sea ice concentration and time-varying solar, volcanic, and carbon dioxide radiative forcings are prescribed. Products include 6-hourly ensemble mean and spread analysis fields on a 2 by 2 degree global latitude-longitude grid, and 3 and 6-hourly ensemble mean and spread forecast (first guess) fields on a global Gaussian T62 grid. Fields are accessible in yearly time series (1 file per parameter) and monthly synoptic time (all parameters per synoptic hour) files.  This dataset provides the first estimates of global tropospheric variability spanning 1851 to 2012 at six-hourly resolution. Fields from 1851 to 1860 are a first attempt at this period and will be improved in future versions. Fields from 1861 to 2011 are most relevant for climate and weather studies.


    20th Century Reanalysis Version 2c uses the same model as version 2 with new sea ice boundary conditions from the COBE-SST2 (Hirahara et al. 2014), new pentad Simple Ocean Data Assimilation with sparse input (SODAsi.2, Giese et al. 2015) sea surface temperature fields from through 2012, Daily High-Resolution-Blended Analyses for Sea Surface Temperature starting with 2013, and additional observations from ISPD version 3.2.9.



    A low pressure bias in marine pressures from the US Maury Collection (Woodruff et al. 2005, Wallbrink et al. 2009, ) appears to have affected the resultant 20CR version 2c mass-related fields (e.g., pressure, geopotential height) from 1851 to about 1865. Please see opportunities for improvement for additional information.



    The Twentieth Century Reanalysis Project version 2c used resources of the National Energy Research Scientific Computing Center managed by Lawrence Berkeley National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Version 2c is a contribution to the international Atmospheric Circulation Reconstructions over the Earth initiative. Support for the Twentieth Century Reanalysis Project is provided by the U.S. Department of Energy Office of Science (BER) and the NOAA Climate Program Office MAPP program.

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Questions? Email Resource Support Contact:

  • datahelp@ucar.edu

Temporal Range

  • Begin:  1850-12-31T2100+00
    End:  2014-12-31T2100+00

Keywords

Resource Type dataset
Temporal Range Begin 1850-12-31T2100+00
Temporal Range End 2014-12-31T2100+00
Temporal Resolution N/A
Bounding Box North Lat 90.0
Bounding Box South Lat -90.0
Bounding Box West Long -180.0
Bounding Box East Long 180.0
Spatial Representation grid
Spatial Resolution 2 degree
1.875 degree
Related Links

Related Resource #1 : NOAA ESRL 20th Century Reanalysis Project Homepage

Related Resource #2 : Atmospheric Circulation Reconstructions over the Earth

Related Resource #3 : Summary of available global reanalysis dataset and collaboration space

Related Resource #4 : COBE SST2 and Sea-Ice dataset

Related Resource #5 : Access individual 20 CR v2 ensemble grids through the NERSC Gateway

Related Resource #6 : Access 20th CR v2c in NetCDF format at ESRL. Monthly and daily means are also available at ESRL
Additional Information N/A
Resource Format WMO GRIB1
Standardized Resource Format GRIB
Asset Size 0 MB
Legal Constraints

Creative Commons Attribution 4.0 International License
Access Constraints None
Software Implementation Language N/A

Resource Support Name N/A
Resource Support Email datahelp@ucar.edu
Resource Support Organization N/A
Distributor NSF NCAR Geoscience Data Exchange
Metadata Contact Name N/A
Metadata Contact Email datahelp@ucar.edu
Metadata Contact Organization NSF NCAR Geoscience Data Exchange

Author Compo, Gilbert P.
Whitaker, Jeffrey S.
Sardeshmukh, Prashant D.
Allan, Robert J.
McColl, Chesley
Yin, Xungang
Giese, Benjamin S.
Vose, Russell S.
Matsui, Nobuki
Ashcroft, Linden
Auchmann, Renate
Benoy, Mac
Bessemoulin, Pierre
Brandsma, Theo
Brohan, Philip
Brunet, Manola
Comeaux, Joseph
Cram, Thomas
Crouthamel, Richard
Groisman, Pavel Y.
Hersbach, Hans
Jones, Philip D.
Jonsson, Trausti
Jourdain, Sylvie
Kelly, Gail
Knapp, Kenneth R.
Kruger, Andries
Kubota, Hisayuki
Lentini, Gianluca
Lorrey, Andrew
Lott, Neal
Lubker, Sandra J.
Luterbacher, Jurg
Marshall, Gareth J.
Maugeri, Maurizio
Mock, Cary J.
Mok, Hing Y.
Nordli, Oyvind
Przybylak, Rajmund
Rodwell, Mark J.
Ross, Thomas F.
Schuster, Douglas
Srnec, Lidija
Valente, Maria Antonia
Vizi, Zsuzsanna
Wang, Xiaolan L.
Westcott, Nancy
Woollen, John S.
Worley, Steven J.
Publisher NSF National Center for Atmospheric Research
Publication Date 2015-03-16
Digital Object Identifier (DOI) https://doi.org/10.5065/D6N877TW
Alternate Identifier d131002
Resource Version N/A
Topic Category climatologyMeteorologyAtmosphere
Progress onGoing
Metadata Date 2025-10-09T01:20:53Z
Metadata Record Identifier edu.ucar.gdex::d131002
Metadata Language eng; USA
Suggested Citation Compo, Gilbert P., Whitaker, Jeffrey S., Sardeshmukh, Prashant D., Allan, Robert J., McColl, Chesley, Yin, Xungang, Giese, Benjamin S., Vose, Russell S., Matsui, Nobuki, Ashcroft, Linden, Auchmann, Renate, Benoy, Mac, Bessemoulin, Pierre, Brandsma, Theo, Brohan, Philip, Brunet, Manola, Comeaux, Joseph, Cram, Thomas, Crouthamel, Richard, Groisman, Pavel Y., Hersbach, Hans, Jones, Philip D., Jonsson, Trausti, Jourdain, Sylvie, Kelly, Gail, Knapp, Kenneth R., Kruger, Andries, Kubota, Hisayuki, Lentini, Gianluca, Lorrey, Andrew, Lott, Neal, Lubker, Sandra J., Luterbacher, Jurg, Marshall, Gareth J., Maugeri, Maurizio, Mock, Cary J., Mok, Hing Y., Nordli, Oyvind, Przybylak, Rajmund, Rodwell, Mark J., Ross, Thomas F., Schuster, Douglas, Srnec, Lidija, Valente, Maria Antonia, Vizi, Zsuzsanna, Wang, Xiaolan L., Westcott, Nancy, Woollen, John S., Worley, Steven J.. (2015). NOAA/CIRES Twentieth Century Global Reanalysis Version 2c. NSF National Center for Atmospheric Research. https://doi.org/10.5065/D6N877TW. Accessed 11 October 2025.

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