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NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables

We have transitioned the data files from netCDF3 to netCDF4-classic format on Monday Oct 20th, 2014.

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:

• T62 Gaussian grid (192x94)
• 88.542N - 88.542S, 0E - 358.125E

Levels:

• Nominal top of atmosphere (NTAT).

Update Schedule:

• Monthly

Download/Plot Data: (Download Issues)

Variable	Statistic	Level	Download File	Create Plot/Subset	File Metadata
Clear Sky Upward Longwave Flux	Monthly Means	Nominal Top of atmosphere	csulf.ntat.mon.mean.nc		File Metadata
Clear Sky Upward Longwave Flux	Monthly Long Term Means	Nominal Top of atmosphere	csulf.ntat.mon.ltm.nc		File Metadata
Clear Sky Upward Longwave Flux	Daily Long Term Means	Nominal Top of atmosphere	csulf.ntat.day.1981-2010.ltm.nc		File Metadata
Clear Sky Upward Longwave Flux	4X Daily Long Term Means	Nominal Top of atmosphere	csulf.ntat.4Xday.1981-2010.ltm.nc		File Metadata
Clear Sky Upward Shortwave Flux	Monthly Means	Nominal Top of atmosphere	csusf.ntat.mon.mean.nc		File Metadata
Clear Sky Upward Shortwave Flux	Monthly Long Term Means	Nominal Top of atmosphere	csusf.ntat.mon.ltm.nc		File Metadata
Clear Sky Upward Shortwave Flux	Daily Long Term Means	Nominal Top of atmosphere	csusf.ntat.day.1981-2010.ltm.nc		File Metadata
Clear Sky Upward Shortwave Flux	4X Daily Long Term Means	Nominal Top of atmosphere	csusf.ntat.4Xday.1981-2010.ltm.nc		File Metadata
Downward Solar Radiation Flux	Monthly Means	Nominal Top of atmosphere	dswrf.ntat.mon.mean.nc		File Metadata
Downward Solar Radiation Flux	Monthly Long Term Means	Nominal Top of atmosphere	dswrf.ntat.mon.ltm.nc		File Metadata
Downward Solar Radiation Flux	Daily Long Term Means	Nominal Top of atmosphere	dswrf.ntat.day.1981-2010.ltm.nc		File Metadata
Downward Solar Radiation Flux	4X Daily Long Term Means	Nominal Top of atmosphere	dswrf.ntat.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	High cloud bottom	pres.hcb.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	High cloud bottom	pres.hcb.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	High cloud bottom	pres.hcb.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	High cloud bottom	pres.hcb.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	High cloud top	pres.hct.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	High cloud top	pres.hct.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	High cloud top	pres.hct.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	High cloud top	pres.hct.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	Low cloud bottom	pres.lcb.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	Low cloud bottom	pres.lcb.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	Low cloud bottom	pres.lcb.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	Low cloud bottom	pres.lcb.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	Low cloud top	pres.lct.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	Low cloud top	pres.lct.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	Low cloud top	pres.lct.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	Low cloud top	pres.lct.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	Middle cloud bottom	pres.mcb.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	Middle cloud bottom	pres.mcb.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	Middle cloud bottom	pres.mcb.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	Middle cloud bottom	pres.mcb.4Xday.1981-2010.ltm.nc		File Metadata
Pressure	Monthly Means	Middle cloud top	pres.mct.mon.mean.nc		File Metadata
Pressure	Monthly Long Term Means	Middle cloud top	pres.mct.mon.ltm.nc		File Metadata
Pressure	Daily Long Term Means	Middle cloud top	pres.mct.day.1981-2010.ltm.nc		File Metadata
Pressure	4X Daily Long Term Means	Middle cloud top	pres.mct.4Xday.1981-2010.ltm.nc		File Metadata
Total cloud cover	Monthly Means	Entire Atmosphere Considered As a Single Layer	tcdc.eatm.mon.mean.nc		File Metadata
Total cloud cover	Monthly Long Term Means	Entire Atmosphere Considered As a Single Layer	tcdc.eatm.mon.ltm.nc		File Metadata
Total cloud cover	Daily Long Term Means	Entire Atmosphere Considered As a Single Layer	tcdc.eatm.day.1981-2010.ltm.nc		File Metadata
Total cloud cover	4X Daily Long Term Means	Entire Atmosphere Considered As a Single Layer	tcdc.eatm.4Xday.1981-2010.ltm.nc		File Metadata
Upward Longwave Radiation Flux	Monthly Means	Nominal Top of atmosphere	ulwrf.ntat.mon.mean.nc		File Metadata
Upward Longwave Radiation Flux	Monthly Long Term Means	Nominal Top of atmosphere	ulwrf.ntat.mon.ltm.nc		File Metadata
Upward Longwave Radiation Flux	Daily Long Term Means	Nominal Top of atmosphere	ulwrf.ntat.day.1981-2010.ltm.nc		File Metadata
Upward Longwave Radiation Flux	4X Daily Long Term Means	Nominal Top of atmosphere	ulwrf.ntat.4Xday.1981-2010.ltm.nc		File Metadata
Upward Solar Radiation Flux	Monthly Means	Nominal Top of atmosphere	uswrf.ntat.mon.mean.nc		File Metadata
Upward Solar Radiation Flux	Monthly Long Term Means	Nominal Top of atmosphere	uswrf.ntat.mon.ltm.nc		File Metadata
Upward Solar Radiation Flux	Daily Long Term Means	Nominal Top of atmosphere	uswrf.ntat.day.1981-2010.ltm.nc		File Metadata
Upward Solar Radiation Flux	4X Daily Long Term Means	Nominal Top of atmosphere	uswrf.ntat.4Xday.1981-2010.ltm.nc		File Metadata

Notes:

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 PSL 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 generally composed of variable abbreviations, averaging period and statistic. Averaging periods include "day" and "mon". Statistics include "mean", "ltm"(long-term mean), and "inter.std" (interannual standard deviation). (variable).(averaging period).(statistic).nc e.g. csulftop.mon.mean.nc
• All data are stored in netCDF files
• The data are divided by variable and year into separate files
• There are 18 files currently
• Files range in size from 849 Kbytes to 44.7 Mbytes
• Current total of 250 Mbytes.
• 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/other_flux/.
• 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:

• /thredds/dodsC/Datasets/ncep.reanalysis.derived/other_gauss/var.time.stat.nc   

Dataset Format and Size:

• PSL standard NetCDF (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 -9.96921e+36f.

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 PSL, 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 PSL, Boulder, Colorado, USA, from their Web site at / in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSL 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 Laboratory: Data Management
  NOAA/ESRL/PSL
  325 Broadway
  Boulder, CO 80305-3328
  psl.data@noaa.gov