Twentieth Century Reanalysis (V1): Summary

Beta 20th Century Reanalysis Monthly Mean Plotting page

One-Line Description:

20th Century Reanalysis contains objectively-analyzed 4-dimensional weather maps and their uncertainty for most of the 1900's.

Temporal Coverage:

6-hourly,daily average and monthly values for 1908/01/01 0z to 1958/12/31 18z.
Long term monthly means, derived from data for years 1921 - 1950.

Spatial Coverage:

2.0 degree latitude x 2.0 degree longitude global grid (180x91).
90N - 90.0S, 0.0E - 358.E.

Levels:

pressure level and single level files. 24 pressure levels (hPa): 1000 , 950 , 900 , 850 , 800 , 750 , 700 , 650 , 600 , 550 , 500 , 450 , 400 , 350 , 300 , 250 , 200 , 150 , 100 , 70 , 50 , 30 , 20 , 10

Update Schedule:

More data will be added to the collection that PSD will distribute. See the complete description of what we plan to carry.

The 20th Century Reanalysis are subdivided into separate files

Daily and 4-times daily

Pressure Level
Monolevel

Monthly

Pressure Level
Monolevel

Usage Restrictions:

RELEASE POLICY: Please use the following citations in any submitted publications using this dataset:
- Compo, G.P., J.S. Whitaker, P.D. Sardeshmukh, N. Matsui, R.J. Allan, X. Yin,B.E. Gleason, R.S. Vose, G. Rutledge, P. Bessemoulin, S. Brönnimann, M. Brunet, R.I. Crouthamel, A.N. Grant, P.Y. Groisman, P.D. Jones, M. Kruk, A.C. Kruger, G.J. Marshall, M. Maugeri, H.Y. Mok, Ø. Nordli, T.F. Ross, R.M. Trigo, X.L. Wang, S.D. Woodruff, S.J. Worley, 2009: The Twentieth Century Reanalysis Project. Bull. Amer. Met. Soc., in preparation.
- Compo,G.P., J.S. Whitaker, and P.D. Sardeshmukh, 2006: Feasibility of a 100 year reanalysis using only surface pressure data. Bull. Amer. Met. Soc., 87, 175-190.
- Whitaker, J.S., G.P.Compo, X. Wei, and T.M. Hamill 2004: Reanalysis without radiosondes using ensemble data assimilation. Mon. Wea. Rev., 132, 1190-1200.

Detailed Description:

The analysis is performed with the Ensemble Filter as described in Compo et al. (2006).Observations of surface pressure and sea level pressure from the International Surface Pressure Databank version1.1 and ICOADS version 2.4 were assimilated every six hours. The short-term forecast ensemble is generated in parallel from 56 9-hour integrations of a state-of-the-art atmospheric general circulation model, the atmospheric component of NCEP's operational Climate Forecast System model (Saha et al. 2006). Briefly, the model has a spatial resolution of nearly 200-km on an irregular Gaussian grid in the horizontal (corresponding to a spherical harmonic representation of model fields truncated at total wavenumber 62, T62). In the vertical, for efficiency, we have reduced the resolution from a finite differencing of 64 levels to 28 levels with no detrimental effects to the reanalysis quality. The model top is at 0.2 hPa. The model has a complete suite of physical parameterizations as described in Kanamitsu et al. 1991) with recent updates detailed in Moorthi et al. (2001). Additional updates to these parameterizations, specific to this version of the model, are described in Saha et al. and include revised solar radiation transfer, boundary layer vertical diffusion, cumulus convection,and gravity wave drag parameterizations. In addition, the cloud liquid water is a prognostic quantity with a simple cloud microphysics parameterization. The radiation interacts with a fractional cloud cover that is diagnostically determined by the predicted cloud liquid water. The specified boundary conditions needed to run the model in atmosphere-only mode are taken from the time-evolving sea surface temperature and sea ice fields of the HadISST1.1 dataset obtained courtesy of the United Kingdom Met Office Hadley Centre Rayner et al. 2003).

Caveats:

Opportunities for Improvement

Citation:

Please note: If you acquire 20th Century Reanalysis data products from PSD, we ask that you acknowledge us in your use of the data. This may be done by including text such as 20th Century Reanalysis data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.cdc.noaa.gov/ in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSD to justify keeping the 20th Century Reanalysis data set freely available online in the future. Thank you!

References:

Compo,G.P., J.S. Whitaker, and P.D. Sardeshmukh, 2006: Feasibility of a 100 year reanalysis using only surface pressure data. Bull. Amer. Met. Soc., 87, 175-190.
Kanamitsu, M, and Coauthors 1991: Recent changes implemented into the global forecast system at NMC. Wea. Forecasting, 6, 425-435. Moorthi, S., H.-L. Pan, and P. Caplan, 2001: Changes to the 2001 NCEP operational MRF/AVN global analysis/forecast system. NWS Tech. Procedures Bulletin 484, 14 pp. [Available online at http://www.nws.noaa.gov/om/tpb/484.htm.]
Rayner, N.A., D.E. Parker, E.B. Horton, C.K. Folland, L.V. Alexander, D.P. Rowell, E.C Kent, and A. Kaplan, 2003: Global analyses of SST, sea ice and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108, 4407, doi:10.1029/2002JD002670.
Saha, S. and Coauthors, 2006: The NCEP Climate Forecast System. J. Climate, 19, 3483-3517. Whitaker, J.S., G.P.Compo, X. Wei, and T.M. Hamill 2004: Reanalysis without radiosondes using ensemble data assimilation. Mon. Wea. Rev., 132, 1190-1200.

Original Source:

Data are courtesy of Gilbert Compo1,2 , Jeff Whitaker2, Prashant Sardeshmukh1,2 and Nobuki Matsui1,2 1. University of Coloraado CIRES-Climate Diagnostics Center 2. NOAA Earth System Research Laboratory - Physical Sciences Division.
Computing resources to produce the dataset were made available through a U.S. Department of Energy Innovative and Novel Computational Impact on Theory and Experiment (INCITE) computing award at the National Energy Research Scientific Computer Center.

Contact:

For help with the dataset please contact Gil Compo, Research Scientist, CIRES University of Colorado Email: compo@colorado.edu
Physical Sciences Division: Data Management
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esrl.psd.data@noaa.gov