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NCEP/NCAR Reanalysis 1:Other Flux

We will be transitioning the data files from netCDF3 to netCDF4-classic format. As a result, the files will be compressed instead of being packed with a scale and offset. As with any netCDF4 file, the NetCDF library will perform the uncompression. We expect the files to be read faster, depending on the application you are using. Values may differe slightly because of precision issues. Please let us know if you run into any problems after first reading our netCDF4 doc . We are also changing the time acces to use 1800 as a reference date for udunits. This should prove easier for users.

Other Grid Types: NCEP Reanalysis Main Page | Pressure Level Data | Surface Data | Surface Flux Data | Other Flux Data |Spectral Coefficents Data | Tropopause Data

Brief Description:

  • NCEP/NCAR Reanalysis 1

Temporal Coverage:

  • 4-times daily, daily and monthly values for 1948/01/01 to present
  • Long term monthly means, derived from data for years 1981 - 2010

Spatial Coverage:

  • T62 Gaussian grid with 192x94 points
  • 88.542N-88.542S, 0E-358.125E
  • All data are stored in netCDF files
  • The data are divided by variable and year into separate files
  • There are 492 files currently
  • Files 52 Mbytes per variable per year
  • Current total of 25.8 Gbytes for 4xDaily and 6.5 Gbytes for daily averages

Levels:

  • ntat: Nominal top of atmosphere
  • eatm: Entire atmosphere
  • hcb: High cloud bottom
  • hct: High cloud top
  • lcb: Low cloud bottom
  • lct: Low cloud top
  • mcb: Middle cloud bottom
  • mct: Middle cloud top

Update Schedule:

  • Daily

Note: All of these variables are six hour averages for the period of the reference time plus six hours.

Variable Statistic Level Download File Create Plot/Subset
Clear sky upward longwave flux 4-times Daily NTAT see list plot
Clear sky upward longwave flux Daily NTAT see list plot
Clear sky upward solar flux 4-times Daily NTAT see list plot
Clear sky upward solar flux Daily NTAT see list plot
Downward solar radiation flux 4-times Daily NTAT see list plot
Downward solar radiation flux Daily NTAT see list plot
Pressure at high cloud bottom 4-times Daily HCB see list plot
Pressure at high cloud bottom Daily HCB see list plot
Pressure at high cloud top 4-times Daily HCT see list plot
Pressure at high cloud top Daily HCT see list plot
Pressure at low cloud bottom 4-times Daily LCB see list plot
Pressure at low cloud bottom Daily LCB see list plot
Pressure at low cloud top 4-times Daily LCT see list plot
Pressure at low cloud top Daily LCT see list plot
Pressure at middle cloud bottom 4-times Daily MCB see list plot
Pressure at middle cloud bottom Daily MCB see list plot
Pressure at middle cloud top 4-times Daily MCT see list plot
Pressure at middle cloud top Daily MCT see list plot
Total cloud cover 4-times Daily EATM see list plot
Total cloud cover Daily EATM see list plot
Upward longwave radiation flux 4-times Daily NTAT see list plot
Upward longwave radiation flux Daily NTAT see list plot
Upward solar radiation flux 4-times Daily NTAT see list plot
Upward solar radiation flux Daily NTAT see list plot

Usage Restrictions:

  • None

Detailed Description:

  • The NCEP/NCAR Reanalysis 1 project is using a state-of-the-art analysis/forecast system to perform data assimilation using past data from 1948 to the present. A large subset of this data is available from PSD in its original 4 times daily format and as daily averages. However, the data from 1948-1957 is a little different, in the regular (non-Gaussian) gridded data. That data was done at 8 times daily in the model, because the inputs available in that era were available at 3Z, 9Z, 15Z, and 21Z, whereas the 4x daily data has been available at 0Z, 6Z, 12Z, and 18Z. These latter times were forecasted and the combined result for this early era is 8x daily. The local ingestion process took only the 0Z, 6Z, 12Z, and 18Z forecasted values, and thus only those were used to make the daily time series and monthly means here.

Caveats:

Related File Naming & Structure Information:

File Names:

    Archive parameters: File names are composed of variable abbreviations,
  • level, and year: (variable).(level).gauss.(year).nc
  • See individual sections. Data in /Datasets/ncep.reanalysis/, Datasets/ncep.reanalysis.dailyavgs/, /Datasets/ncep.reanalysis.derived/
  • 4x daily data are available from ftp.cdc.noaa.gov in /Datasets/ncep.reanalysis/other_gauss/.
  • The 4x data files are quite large, so you may only be able to download them if you have a fast network connection.
  • Daily averages are available from ftp.cdc.noaa.gov in /Datasets/ncep.reanalysis.dailyavgs/other_gauss/.

Dataset Format and Size:

  • PSD standard NetCDF most are (packed).
  • All data are stored in netCDF files
  • The data are divided by variable and year into separate files
  • There are 492 files currently
  • Files 52 Mbytes per variable per year
  • Current total of 25.8 Gbytes for 4xDaily and 6.5 Gbytes for daily averages
  • If you would like datasets on a media such as tape, you will need to get them from another institution. NCAR (link) provides such a service for their datasets.

Missing Data:

  • None now. The following dates in 2002 and 2003 were missing for the tcdc variable, but were filled in on 2003/05/02. You may wish to re-FTP these files. Missing dates for tcdc:
    2002/01/14, 2002/04/21, 2002/05/08, 2002/06/24, 2002/10/25, 2002/11/26, 2003/02/23, 2003/03/25

Citation:

  • For dataset source, please cite:Kalnay et al.,The NCEP/NCAR 40-year reanalysis project, Bull. Amer. Meteor. Soc., 77, 437-470, 1996.
  • Please note: If you acquire NCEP 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 NCEP Reanalysis data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/ 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 NCEP Reanalysis data set freely available online in the future. Thank you!

References:

  • March, 1996 BAMS

Original Source:

  • NOAA National Center for Environmental Prediction

Contact:

  • Physical Sciences Division: Data Management
    NOAA/ESRL/PSD
    325 Broadway
    Boulder, CO 80305-3328
    esrl.psd.data@noaa.gov