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Restrictions | Details | Caveats | File Naming | Citation | References | Original Source | Contact
CPC Merged Analysis of Precipitation (CMAP)
- Monthly and pentad global gridded precipitation means. It includes a standard and enhanced version (with NCEP Reanalysis) from 1979 to near the present. More Details...
- Irregular. Try to follow CPC
|Variable||Statistic||Level||Download File||Create Plot/Subset|
|Precipitation||Mean (Standard Monthly)||' '||precip.mon.mean.nc|
|Precipitation||Mean (Enhanced Monthly)||' '||precip.mon.mean.nc|
|Precipitation||Long Term Mean (Standard Monthly)||' '||precip.mon.ltm.nc|
|Precipitation||Long Term Mean (Enhanced Monthly)||' '||precip.mon.ltm.nc|
|Precipitation||Mean (Standard Pentad)||' '||precip.pentad.mean.nc|
|Precipitation||Mean (Enhanced Pentad)||' '||precip.pentad.mean.nc|
The monthly data set consists of two files containing monthly averaged
precipitation rate values. Values are obtained from 5 kinds of satellite
estimates (GPI,OPI,SSM/I scattering, SSM/I emission and MSU). The enhanced
file also includes blended NCEP/NCAR Reanalysis Precipitation values. The
other just includes the satellite estimates.
Pentad data is also available.
- This data set consists of monthly averaged precipitation rate values (mm/day). The data range is approximately 0 to 70mm/day. The pentad dataset consists of 73 pentads per year with the 12th pentad covering Feb 25-Mar 1 whether or not there is a leap year. The pentad starts on the date stored in the netCDF file.
- Reading in GrADS: If you read the data in GrADS, it will assume the values are 5 days apart the entire time period including leap years. This isn't correct so you may get the wrong dates. To handle this in GrADS, you can use a ddf file rather than using sdfopen and set the calendar options to 365_day_calendar. Or, you can just use the "t" cvalues as each full year has 73 values starting Jan 1.
OpenDap File Names:
Dataset Format and Size:
- PSD standard NetCDF 13 Mbyte file for each monthly file.
- PSD standard NetCDF 80 Mbyte file for each pentad file.
- Missing data is flagged with a value of -9.96921e+36f. The enhanced version has no missing; the standard version does.
- Xie, P., and P.A. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539 - 2558.
- Please note: If you acquire CMAP Precipitation 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 CMAP Precipitation 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 CMAP Precipitation data set freely available online in the future. Thank you!
- Huffman, G. J. and co-authors, 1997: The Global Precipitation Climatology Project (GPCP) combined data set. Bull. Amer. Meteor. Soc., 78, 5-20.
- Reynolds, R. W., 1988: A real-time global sea surface temperature analysis. J. Climate, 1, 75-86.
- Spencer, R. W., 1993: Global oceanic precipitation from the MSU during 1979-91 and comparisons to other climatologies. J. Climate, 6, 1301-1326.
- Xie P., and P. A. Arkin, 1997: Global precipitation: a 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539-2558.
- Dr. Pingping Xie
National Centers for Environmental Prediction, #800A
National Oceanic and Atmospheric Administration
Washington, DC 20233
original ftp: ftp://ftp.cpc.ncep.noaa.gov/precip/cmap/
Physical Sciences Division: Data Management
Boulder, CO 80305-3328