NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables

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:

  • Surface or near the surface (.995 sigma level)
  • The variables on sigma level 0.995 are: air, rhum, uwnd, vwnd and wspd.
  • Also, precipitable water is included here, because it is a 3-D file on a 2.5 degree grid, but it is not a surface value, but rather for the entire atmospheric column

Update Schedule:

  • Monthly

Download/Plot Data:

Variable Statistic Level Download File Create Plot/Subset File Metadata
Air Temperature Monthly Means Surface air.mon.mean.nc plot File Metadata
Air Temperature Monthly Long Term Means Surface air.mon.ltm.nc plot File Metadata
Air Temperature Monthly Means Surface air.sig995.mon.mean.nc plot File Metadata
Air Temperature Monthly Long Term Means Surface air.sig995.mon.ltm.nc plot File Metadata
Air Temperature Daily Long Term Means Surface air.sig995.day.1981-2010.ltm.nc plot File Metadata
Air Temperature 4X Daily Long Term Means Surface air.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
Surface Lifted Index Monthly Means Surface lftx.sfc.mon.mean.nc plot File Metadata
Best (4-layer) Lifted Index Monthly Means Surface lftx4.sfc.mon.mean.nc plot File Metadata
Omega (dp/dt) Monthly Means Surface omega.sig995.mon.mean.nc plot File Metadata
Omega (dp/dt) Monthly Long Term Means Surface omega.sig995.mon.ltm.nc plot File Metadata
Omega (dp/dt) Daily Long Term Means Surface omega.sig995.day.1981-2010.ltm.nc plot File Metadata
Omega (dp/dt) 4X Daily Long Term Means Surface omega.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
Potential Temperature Monthly Means Surface pottmp.sig995.mon.mean.nc plot File Metadata
Potential Temperature Monthly Long Term Means Surface pottmp.sig995.mon.ltm.nc plot File Metadata
Potential Temperature Daily Long Term Means Surface pottmp.sig995.day.1981-2010.ltm.nc plot File Metadata
Potential Temperature 4X Daily Long Term Means Surface pottmp.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
Precipitable Water Content Monthly Means Surface pr_wtr.eatm.mon.mean.nc plot File Metadata
Precipitable Water Content Monthly Long Term Means Surface pr_wtr.eatm.mon.ltm.nc plot File Metadata
Precipitable Water Content Daily Long Term Means Surface pr_wtr.eatm.day.1981-2010.ltm.nc plot File Metadata
Precipitable Water Content 4X Daily Long Term Means Surface pr_wtr.eatm.4Xday.1981-2010.ltm.nc plot File Metadata
Precipitable Water Content Monthly Means Surface pr_wtr.mon.mean.nc plot File Metadata
Precipitable Water Content Monthly Long Term Means Surface pr_wtr.mon.ltm.nc plot File Metadata
Surface Pressure Monthly Means Surface pres.mon.mean.nc plot File Metadata
Surface Pressure Monthly Long Term Means Surface pres.mon.ltm.nc plot File Metadata
Surface Pressure Daily Long Term Means Surface pres.day.1981-2010.ltm.nc plot File Metadata
Surface Pressure 4X Daily Long Term Means Surface pres.4Xday.1981-2010.ltm.nc plot File Metadata
Surface Pressure Monthly Means Surface pres.sfc.mon.mean.nc plot File Metadata
Relative Humidity Monthly Means Surface rhum.mon.mean.nc plot File Metadata
Relative Humidity Monthly Long Term Means Surface rhum.mon.ltm.nc plot File Metadata
Relative Humidity Monthly Means Surface rhum.sig995.mon.mean.nc plot File Metadata
Relative Humidity Monthly Long Term Means Surface rhum.sig995.mon.ltm.nc plot File Metadata
Relative Humidity Daily Long Term Means Surface rhum.sig995.day.1981-2010.ltm.nc plot File Metadata
Relative Humidity 4X Daily Long Term Means Surface rhum.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
Sea Level Pressure Monthly Means Sea Level slp.mon.mean.nc plot File Metadata
Sea Level Pressure Monthly Long Term Means Sea Level slp.mon.ltm.nc plot File Metadata
Sea Level Pressure Daily Long Term Means Sea Level slp.day.1981-2010.ltm.nc plot File Metadata
Sea Level Pressure 4X Daily Long Term Means Sea Level slp.4Xday.1981-2010.ltm.nc plot File Metadata
u-wind Monthly Means Surface uwnd.mon.mean.nc plot File Metadata
u-wind Monthly Long Term Means Surface uwnd.mon.ltm.nc plot File Metadata
u-wind Monthly Means Surface uwnd.sig995.mon.mean.nc plot File Metadata
u-wind Monthly Long Term Means Surface uwnd.sig995.mon.ltm.nc plot File Metadata
u-wind Daily Long Term Means Surface uwnd.sig995.day.1981-2010.ltm.nc plot File Metadata
u-wind 4X Daily Long Term Means Surface uwnd.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
v-wind Monthly Means Surface vwnd.mon.mean.nc plot File Metadata
v-wind Monthly Long Term Means Surface vwnd.mon.ltm.nc plot File Metadata
v-wind Monthly Means Surface vwnd.sig995.mon.mean.nc plot File Metadata
v-wind Monthly Long Term Means Surface vwnd.sig995.mon.ltm.nc plot File Metadata
v-wind Daily Long Term Means Surface vwnd.sig995.day.1981-2010.ltm.nc plot File Metadata
v-wind 4X Daily Long Term Means Surface vwnd.sig995.4Xday.1981-2010.ltm.nc plot File Metadata
Wind Speed Monthly Means Surface wspd.mon.mean.nc plot File Metadata
Wind Speed Monthly Long Term Means Surface wspd.mon.ltm.nc plot File Metadata
Wind Speed Monthly Means Surface wspd.sig995.mon.mean.nc plot File Metadata
Wind Speed Monthly Long Term Means Surface wspd.sig995.mon.ltm.nc plot File Metadata

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:

  • 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/surface/var.time.stat.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