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Palmer Drought Severity Index (PDSI) from NCAR

Brief Description:

  • Monthly gridded global PDSI (Palmer Drought Severity Index) values from 1850-2010 from NCAR. More Details....

Temporal Coverage:

  • 1870/01 to 2005/12
  • 1850/01 to 2014/12 (self-calibrated)

Spatial Coverage:

  • 2.5 degrees latitude by 2.5 degrees longitude global grid (144x55)
  • 58.75S,76.25N ; -178.75W,178.75E


  • N/A

Update Schedule:

  • Irregular, when source updates

Download/Plot Data: (FTP Access)

Variable Statistic Level Download File Create Plot/Subset
PDSI Monthly Mean: self-calibrated Surface pdsi.mon.mean.selfcalibrated.nc plot
PDSI Monthly Mean: Surface pdsi.mon.mean.nc plot

Usage Restrictions:

  • Please contact the dataset's author to let him know of your intended use adai@ucar.edu

Detailed Description:

  • PDSI from the Dai dataset. The Palmer Drought Severity Index (PDSI) is devised by Palmer (1965) to represent the severity of dry and wet spells over the U.S. based on monthly temperature and precipitation data as well as the soil-water holding capacity at that location. These data consist of the monthly PDSI over global land areas from 1850 to 2010. Different precipitation/temperature datasets are used in the different files. Update and more information are available at CGD (Climate and Global Dynamics Division).
    Please let the author, Dai at adai@ucar.edu, know what you are using the dataset for.


  • None

Related File Naming & Structure Information:

File Names:

  • pdsi.mon.mean.nc   (In directory: /Datasets/dai_pdsi/)
  • pdsi.mon.mean.selfcalibrated.nc   (In directory: /Datasets/dai_pdsi/)

OpenDap File Names:
  • /thredds/dodsC/Datasets/dai_pdsi/pdsi.mon.mean.selfcalibrated.nc   
  • /thredds/dodsC/Datasets/dai_pdsi/pdsi.mon.mean.nc   

Dataset Format and Size:

  • PSL standard NetCDF3 61 Mbyte self-calibrated file
  • PSL standard NetCDF3 51 Mbyte non self-calibrated file

Missing Data:

  • Missing data is flagged with a value of -99999.


  • Dai, A., K. E. Trenberth, and T. Qian, 2004: A global data set of Palmer Drought Severity Index for 1870-2002: Relationship with soil moisture and effects of surface warming. J. Hydrometeorology, 5, 1117-1130.
  • Please note: If you acquire Dai Palmer Drought Severity Index 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 Dai Palmer Drought Severity Index 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 Dai Palmer Drought Severity Index data set freely available online in the future. Thank you!


  • Dai, A., 2011a: Characteristics and trends in various forms of the Palmer Drought Severity Index (PDSI) during 1900-2008. J. Geophys. Res., 116, D12115, doi:10.1029/2010JD015541.
  • Dai, A., 2011b: Drought under global warming: A review. Wiley Interdisciplinary Reviews: Climate Change, 2, 45-65. DOI: 10.1002/wcc.81.
  • Chen, M., P. Xie, J.E. Janowiak, and P.A. Arkin, 2002: Global land precipitation: a 50-yr monthly analysis based on gauge observations. J. Hydrometeorol., 3, 249-266.
  • Dai, A., I. Fung, and A. D. Del Genio, 1997: Surface observed global land precipitation variations during 1900-1988. J. Climate, 10, 2943-2962.
  • Dai, A., K. E. Trenberth, and T. Karl, 1998: Global variations in droughts and wet spells: 1900-1995. Geophys. Res. Lett., 25, 3367-3370.
  • Dai, A., K. E. Trenberth, and T. Qian, 2004: A global data set of Palmer Drought Severity Index for 1870-2002: Relationship with soil moisture and effects of surface warming. J. Hydrometeorol., in press.
  • Jones, P.D., and A. Moberg, 2003: Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Climate, 16, 206-223.
  • Palmer, W. C, 1965: Meteorological Drought. Res. Paper No.45, 58pp., Dept. of Commerce, Washington, D.C.
  • Webb, R. S., C. E. Rosenzweig, and E. R. Levine, 1993: Specifying land surface characteristics in general circulation models: soil profile dataset and derived water-holding capacities. Global Biogeochem. Cycles, 7, 97-108.

Original Source:


  • Physical Sciences Laboratory: Data Management
    325 Broadway
    Boulder, CO 80305-3328