The Twentieth Century Reanalysis Project, supported by the Earth System Research Laboratory Physical Sciences Division from NOAA and the University of Colorado CIRES Climate Diagnostics Center, is an effort to produce a global reanalysis dataset spanning a portion of the nineteenth century and the entire twentieth century (1871 - near present), assimilating only surface observations of synoptic pressure, monthly sea surface temperature and sea ice distribution. 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. Ensemble grids, spectral coefficients, and other information will available by offline request in the future.

The Twentieth Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center managed by Lawrence Berkeley National Laboratory and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively.

Note: Version 2c of this reanalysis (running from 1851 - 2011) is the recommended research version. Please see ds131.2 to access Version 2c.

RELEASE POLICY: Please use the citations listed below (See Publications section below) in any submitted publications using this dataset.

Additionally, papers using the Twentieth Century Reanalysis Project dataset are requested to include the following text in their acknowledgements:

Support for the Twentieth Century Reanalysis Project dataset is provided by the U.S. Department of Energy, Office of Science Innovative and Novel Computational Impact on Theory and Experiment (DOE INCITE) program, and Office of Biological and Environmental Research (BER), and by the National Oceanic and Atmospheric Administration Climate Program Office.