On this page: Temporal Coverage | Spatial Coverage | Levels | Update Schedule | Download/Plot Data | Analysis Tools
Restrictions | Details | Caveats | File Naming | Citation | References | Original Source | Contact

NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables: Pressure Level

NCEP Reanalysis data is delayed due to issues at NCEP. We are working on the updates.
We have transitioned the data files from netCDF3 to netCDF4-classic format on Monday Oct 20th.

Brief Description:

  • NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables.

Temporal Coverage:

  • Daily and Monthly Values for 1948/01 - present.
  • Long term monthly means, derived from data for years 1981 - 2010.

Spatial Coverage:

  • 2.5 degree latitude x 2.5 degree longitude global grid (144x73).
  • 90N - 90S, 0E - 357.5E

Levels:

  • 17 pressure levels (hPa): 1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10
  • some variables not defined at all levels

Update Schedule:

  • Monthly

Download/Plot Data:

Variable Statistic Level Download File Create Plot/Subset File Metadata
Air Temperature Monthly Means Multiple levels air.mon.mean.nc plot File Metadata
Air Temperature Monthly Long Term Means Multiple levels air.mon.ltm.nc plot File Metadata
Air Temperature Daily Long Term Means Multiple levels air.day.1981-2010.ltm.nc plot File Metadata
Air Temperature 4X Daily Long Term Means Multiple levels air.4Xday.1981-2010.ltm.nc plot File Metadata
Air Temperature Monthly Interannual Standard Deviation (1981-2010) Multiple levels air.mon.inter.std.nc plot File Metadata
Air Temperature Monthly Total Standard Deviation (1981-2010) Multiple levels air.mon.total.std.nc plot File Metadata
Geopotential height Monthly Means Multiple levels hgt.mon.mean.nc plot File Metadata
Geopotential height Monthly Long Term Means Multiple levels hgt.mon.ltm.nc plot File Metadata
Geopotential height Daily Long Term Means Multiple levels hgt.day.1981-2010.ltm.nc plot File Metadata
Geopotential height 4X Daily Long Term Means Multiple levels hgt.4Xday.1981-2010.ltm.nc plot File Metadata
Geopotential height Monthly Interannual Standard Deviation (1981-2010) Multiple levels hgt.mon.inter.std.nc plot File Metadata
Geopotential height Monthly Total Standard Deviation (1981-2010) Multiple levels hgt.mon.total.std.nc plot File Metadata
Omega (dp/dt) Monthly Means Multiple levels omega.mon.mean.nc plot File Metadata
Omega (dp/dt) Monthly Long Term Means Multiple levels omega.mon.ltm.nc plot File Metadata
Omega (dp/dt) Daily Long Term Means Multiple levels omega.day.1981-2010.ltm.nc plot File Metadata
Omega (dp/dt) 4X Daily Long Term Means Multiple levels omega.4Xday.1981-2010.ltm.nc plot File Metadata
Omega (dp/dt) Monthly Interannual Standard Deviation (1981-2010) Multiple levels omega.mon.inter.std.nc plot File Metadata
Omega (dp/dt) Monthly Total Standard Deviation (1981-2010) Multiple levels omega.mon.total.std.nc plot File Metadata
Potential Temperature Monthly Means Multiple levels pottmp.mon.mean.nc plot File Metadata
Potential Temperature Monthly Long Term Means Multiple levels pottmp.mon.ltm.nc plot File Metadata
Relative Humidity Monthly Means Multiple levels rhum.mon.mean.nc plot File Metadata
Relative Humidity Monthly Long Term Means Multiple levels rhum.mon.ltm.nc plot File Metadata
Relative Humidity Daily Long Term Means Multiple levels rhum.day.1981-2010.ltm.nc plot File Metadata
Relative Humidity 4X Daily Long Term Means Multiple levels rhum.4Xday.1981-2010.ltm.nc plot File Metadata
Relative Humidity Monthly Total Standard Deviation (1981-2010) Multiple levels rhum.mon.total.std.nc plot File Metadata
Specific Humidity Monthly Means Multiple levels shum.mon.mean.nc plot File Metadata
Specific Humidity Monthly Long Term Means Multiple levels shum.mon.ltm.nc plot File Metadata
Specific Humidity Daily Long Term Means Multiple levels shum.day.1981-2010.ltm.nc plot File Metadata
Specific Humidity 4X Daily Long Term Means Multiple levels shum.4Xday.1981-2010.ltm.nc plot File Metadata
Specific Humidity Monthly Interannual Standard Deviation (1981-2010) Multiple levels shum.mon.inter.std.nc plot File Metadata
u-wind Monthly Means Multiple levels uwnd.mon.mean.nc plot File Metadata
u-wind Monthly Long Term Means Multiple levels uwnd.mon.ltm.nc plot File Metadata
u-wind Daily Long Term Means Multiple levels uwnd.day.1981-2010.ltm.nc plot File Metadata
u-wind 4X Daily Long Term Means Multiple levels uwnd.4Xday.1981-2010.ltm.nc plot File Metadata
u-wind Monthly Interannual Standard Deviation (1981-2010) Multiple levels uwnd.mon.inter.std.nc plot File Metadata
u-wind Monthly Total Standard Deviation (1981-2010) Multiple levels uwnd.mon.total.std.nc plot File Metadata
v-wind Monthly Means Multiple levels vwnd.mon.mean.nc plot File Metadata
v-wind Monthly Long Term Means Multiple levels vwnd.mon.ltm.nc plot File Metadata
v-wind Daily Long Term Means Multiple levels vwnd.day.1981-2010.ltm.nc plot File Metadata
v-wind 4X Daily Long Term Means Multiple levels vwnd.4Xday.1981-2010.ltm.nc plot File Metadata
v-wind Monthly Interannual Standard Deviation (1981-2010) Multiple levels vwnd.mon.inter.std.nc plot File Metadata
v-wind Monthly Total Standard Deviation (1981-2010) Multiple levels vwnd.mon.total.std.nc plot File Metadata
Wind Speed Monthly Means (from daily data) Multiple levels wspd.mon.mean.nc plot File Metadata
Wind Speed Monthly Long Term Means (from daily data) Multiple levels wspd.mon.ltm.nc plot File Metadata

Note:

These variables are averages of instantaneous values at the 4 reference times; 0,6,12 and 18z over the averaging period (month, day).

Availability and usage restrictions:


Note:

These variables are instantaneous values at the reference time. These variables are averages of instantaneous values at the 4 reference times; 0,6,12 and 18z over the averaging period (month, day)

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:

  • None

Related File Naming & Structure Information:

File Names:

  • Archive parameters: File names are composed of variable abbreviations, averaging period and statistic. Averaging periods include "day" and "mon". Statistics include "mean", "ltm"(long-term mean), "inter.std" (interannual standard deviation), "intra.std" (intra-annual standard deviation).

    (variable).(averaging period).(statistic).nc (e.g. hgt.mon.mean.nc)

  • Data set format and size:
  • All data are stored in netCDF files
  • There are 64 files currently
  • Sizes range from 43 Kbytes to 443 Mbytes
  • Current total of 3.8 Gbytes
  • var.time.stat.nc   (In directory: /Datasets/ncep.reanalysis.derived/)
  • Files are available by anonymous FTP from ftp.cdc.noaa.gov in /Datasets/ncep.reanalysis.derived/surface.
  • Archive parameters: File names are generally composed of variable abbreviations, averaging period and statistic. Averaging periods include "day" and "mon". Statistics include "mean", "ltm"(long-term mean), "inter.std" (interannual standard deviation). (variable).(averaging period).(statistic).nc

OpenDap File Names:

  • http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/ncep.reanalysis.derived/(variable).(averaging period).(statistic).nc (e.g. hgt.mon.mean.nc)

Dataset Format and Size:

  • PSD standard NetCDF xx (packed).
  • All data are stored in netCDF files
  • The data are divided by variable and year into separate files
  • There are 48 files currently
  • Files range in size from 167 Kbytes to 26 Mbytes
  • Current total of 377 Mbytes

Missing Data:

  • Missing data is flagged with a value of 32767s.

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 Derived 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 Derived 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 Derived 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