NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables If you don't know where to find a variable, you can search this table. One-Line 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 1968 - 1996. Spatial Coverage: * T62 Gaussian grid (192x94) * 88.542N - 88.542S, 0E - 358.125E Levels: * Surface or near the surface Update Schedule: * Monthly * All variables are available except net longwave radiation and net shortwave radiation, which are updated sporadically Download/Plot Data: These variables are forecasts valid 6 hours after the reference time. 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), "3_10"(3-10 day filtered std) (variable).(averaging period).(statistic).nc Variable Statistic Level Download File Create Plot/Subset Air Temperature at 2 meters Monthly Mean Surface air2m.mon.mean.nc plot Potential evaporation rate Monthly Mean (ltm, total.std) Surface pevpr.mon.mean.nc plot Water runoff Monthly Mean (ltm, inter,std,total.std) Surface runof.mon.mean.nc plot Specific humidity at 2 meters Monthly Mean Surface shum2m.mon.mean.nc plot Volumetric soil moisture (0-10 cm) Monthly Mean (ltm) 0-10 cm soilw.mon.mean.nc plot Volumetric soil moisture (10-200cm) Monthly Mean (ltm) 10-200cm soilw200.mon.mean.nc plot Skin Temperature Monthly Mean (ltm day ltm) Surface skt.mon.mean.nc plot § U-wind at 10 m Monthly Mean 10m uwnd10m.mon.mean.nc plot V-wind at 10 m Monthly Mean 10m vwnd10m.mon.mean.nc plot These variables are 6 hour averages starting at the reference time. Variable Statistic Level Download File Create Plot/Subset Cloud forcing net longwave flux Monthly Mean (LTM) Surface cfnlf.mon.mean.nc plot Clear sky downward longwave flux Monthly Mean (LTM) Surface csdlf.mon.mean.nc plot Clear sky downward solar flux Monthly Mean (LTM) Surface csdsf.mon.mean.nc plot Ground heat flux Monthly Mean (LTM) Surface gflux.mon.mean.nc plot Latent heat net flux Monthly Mean (LTM,inter.std) Surface lhtfl.mon.mean.nc plot Near IR beam downward solar flux Monthly Mean (LTM) Surface nbdsf.mon.mean.nc plot Net longwave radiation Monthly Mean (LTM) Surface nlwrs.mon.mean.nc plot Net shortwave radiation Monthly Mean (LTM) Surface nswrs.mon.mean.nc plot Precipitation rate Monthly Mean (LTM, Day LTM. inter.std total.std) Surface prate.mon.mean.nc plot Sensible heat net flux Monthly Mean (LTM inter.std) Surface shtfl.mon.mean.nc plot Zonal component of momentum flux Monthly Mean (LTM) Surface uflx.mon.mean.nc plot Zonal gravity wave stress Monthly Mean (LTM) Surface ugwd.mon.mean.nc plot Upward longwave radiation flux Monthly Mean (LTM) Surface ulwrf.mon.mean.nc plot Meridional component of momemtum flux Monthly Mean (LTM) Surface vflx.mon.mean.nc plot Meridional gravity wave stress Monthly Mean (LTM) Surface vgwd.mon.mean.nc plot Land-sea mask time invariant Surface lsmask.19294.nc plot none Usage Restrictions: * None Detailed Description: * The NCEP/NCAR Reanalysis project is using a state-of-the-art analysis/forecast system to perform data assimilation using past data from 1948 to the present. A subset of this data has been processed to create monthly means of a subset of the original data. There are also files containing data from variables derived from the reanalysis and some other statistics. Information about the 4 times and daily data is available, as well. Caveats: * Please read the problem list before using the data. * The netCDF data files for the NCEP/NCAR Reanalysis variable PEVPR (files named pevpr.sfc.gauss.YY.nc or pevpr.sfc.gauss.YYYY.nc) may have incorrect units for the pevpr (Potential Evaportion Rate) variable. The correct units are watts per meter squared (W/m^2). § The skt.sfc files contain skin temperature as described in the March, 1996 BAMS article. As such, over land and sea ice, the temperature is a prognostic variable. Over open water, the skin temperature is fixed at its initial value; i.e., the Reynolds SST as seen by the model. The Reynolds' SST analyses were done weekly and the reconstructed SST done monthly. The analyses were linearly interpolated to daily values which were used for all four analyses. The following variables are 6 hour forecast values valid 6 hours after the reference time: air, air.2m, icec, pres, runof, sfcr, shum.2m, soilw.0-10cm, soilw.10-200cm, tmax.2m, tmin.2m, tmp.0-10cm, tmp.10-200cm, tmp.300cm, uwnd.10m, vwnd.10m, weasd, land The following variables are six hour averages for the period of the reference time plus six hours: cfnlf, cfnsf, cprat, csdlf, csdsf, dlwrf, dswrf, gflux, lhtfl, nbdsf, nddsf, prate, shtfl, uflx, ugwd, ulwrf, uswrf, vbdsf, vddsf, vflx, vgwd, nlwrs, nswrs Related File Naming & Structure Information: File Names: * The naming convention of the files is generally variable.averagingperiod.statistic.nc where variable is netcdf variable name averagingperiod is time period over which data is averaged (day,mon) statistic is type of data (mean, long-term mean(ltm), etc) Some files have the level included with the variable names e.g. air2m.mon.mean.nc Here the file should be read with the variable of 'air' _____________________________________________________________ OpenDap File Names: * http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/ncep.reanalysi s.derived/surface_flux/variable.averagingperiod.statistic.nc. Information is available on the time period of the files and how the different statistics were calculated. Jump to: Other General Information _________________________________________________________________ All data are stored in netCDF files The data are divided by variable and statistic There are 60 files currently, ranging in size from 73 Kbytes to 44.7 Mbytes The total disk space consumed by this category is currently 1.1 Gbytes var.time.stat.nc (In directory: /Datasets/ncep.reanalysis.derived/surface_flux/) Dataset Format and Size: * PSD standard NetCDF 311 Mbyte file for each monthly file (packed). * PSD standard NetCDF 30 Mbyte file for each long term mean file (packed). 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 U.S. Department of Commerce | National Oceanic and Atmospheric Administration Earth System Research Laboratory | Physical Sciences Division http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.derived .surfaceflux.html