Precipitation

Interpolating precipitation over large geographic areas is one of the more challenging tasks in climate science.  For Montana the Montana Climate Office is evaluating various precipitation products each of which have their advantages and disadvantages.  Initial investigations indicate that there is opportunity to develop an improved product that better represents precipitation patterns in Montana.  This set of precipitation maps utilizes the Daymet product, but similar maps could be developed utilizing other products.  Daymet is higher-resolution and encompasses the full area-of-interest compared to other publicly available products.

Click on a heading below to expose the information for that topic heading.

Mean annual precipitation for the years 1981-2010Online map of mean annual precipitation (Web application)

Image of mean annual precipitation map (JPEG)

Print version of mean annual precipitation map (PDF)

Mean annual precipitation for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. The precipitation surface is derived from elevation and daily observations of precipitation from ground-based meteorological stations.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was summed for each year in the period 1981 through 2010.  The 30-year annual mean was calculated from the annual sums for all years in the period.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.htm
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

Mean annual frequency of precipitation for the years 1981-2010Online map of mean annual frequency of precipitation (Web application)

Image of mean annual frequency of precipitation map (JPEG)

Print version of mean annual frequency of precipitation map (PDF)

Mean annual frequency of precipitation for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. Frequencies are based on days when Daymet precipitation was greater than zero.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was assessed to determine if precipitation had occurred on each day.  The days of precipitation were counted for each year in the period 1981 through 2010.  The 30-year annual mean was calculated from the annual count for all years in the period.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.html
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

Mean seasonal precipitation for the years 1981-2010 Online map of mean seasonal precipitation (Web application)

Image of mean seasonal precipitation map (JPEG)

Print version of mean seasonal precipitation map (PDF)

Mean seasonal precipitation in inches for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. The precipitation surface is derived from elevation and daily observations of precipitation from ground-based meteorological stations.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was summed for each season in each year in the period 1981 through 2010.  The 30-year annual mean was calculated from the seasonal sums for all years in the period.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.html
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

Mean seasonal percent of annual precipitation for the years 1981-2010Mean seasonal percent of annual precipitation (Web application)

Image of mean seasonal percent of annual precipitation map (JPEG)

Print version of mean seasonal percent of annual precipitation map (PDF)

Mean seasonal percent of annual precipitation in inches for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. The precipitation surface is derived from elevation and daily observations of precipitation from ground-based meteorological stations.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was summed for each season in each year in the period 1981 through 2010.  The 30-year mean for each season was calculated from the seasonal sums for all years in the period. The percentage was derived from the ratio of the 30-year mean seasonal precipitation to the 30-year mean annual precipitation.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.html
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

Mean monthly precipitation for the years 1981-2010 Online map of mean monthly precipitation (Web application)

Image of mean monthly precipitation map (JPEG)

Print version of mean monthly precipitation map (PDF)

Mean monthly precipitation in inches for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. The precipitation surface is derived from elevation and daily observations of precipitation from ground-based meteorological stations.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was summed for each month in each year in the period 1981 through 2010.  The 30-year mean for each month was calculated from the monthly sums for all years in the period.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.html
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

Mean monthly percent of annual precipitation for the years 1981-2010 Online map of mean monthly percent of annual precipitation (Web application)

Image of geographic mean monthly percent of annual precipitation map (JPEG)

Print version of geographic mean monthly percent of annual precipitation map (PDF)

Mean monthly percent of annual precipitation for the years 1981-2010 from Daymet. Daymet is produced by the Oak Ridge National Laboratories from methods originally developed at the University of Montana. The precipitation surface is derived from elevation and daily observations of precipitation from ground-based meteorological stations.

For each 1-kilometer square area in the area-of-interest the daily interpolated precipitation from Daymet was summed for each month in each year in the period 1981 through 2010.  The 30-year mean for each month was calculated from the monthly sums for all years in the period. The percentage was derived from the ratio of the 30-year mean monthly precipitation to the 30-year mean annual precipitation.

Content Credits:

  • The Montana Climate Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/Readme.html
  • The Daymet precipitation product is provided by the Oak Ridge National Laboratories (http://daymet.ornl.gov/). Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.
  • Components referenced in the Montana Climate Office geographic area-of-interest map

The PRISM (Parameter elevation Regression on Independent Slopes Model) Climate Group dataset available at Oregon State University, http://prism.oregonstate.edu. The Montana Office source for this data can be found at ftp://mco.cfc.umt.edu/prcp/PRISM/Readme.html

The Livneh dataset available at the University of Washington at ftp://ftp.hydro.washington.edu/pub/blivneh/CONUS/readme.txt. Livneh, B., E. A. Rosenberg, C. Lin, B. Nijssen, V. Mishra, K. M. Andreadis, E. P. Maurer, and D. P. Lettenmaier, 2013: A Long-Term Hydrologically Based Dataset of Land Surface Fluxes and States for the Conterminous United States: Update and Extensions. J. Climate, 26, 9384~9392. The Montana Climate Office will be hosting this dataset in 2015.

The Montana Department of Environmental Quality (DEQ) recently released their estimate of average annual precipitation for the years 1981-2010. That dataset is available for download through the Montana State Library ftp://ftp.geoinfo.msl.mt.gov/Data/Spatial/NonMSDI/Geodatabases/mt_1981-2010_AveAnnPrecip.zip

The University of Idaho Gridded Surface Meterological Dataset is a gridded product that integrates PRISM and NLDAS-2 datasets to derive a spatially and temporally complete, high-resolution (4-km) gridded dataset of surface meteorological variables required in ecological modeling for the contiguous United States from 1979-present. This dataset and additional information is available at http://climate.nkn.uidaho.edu/METDATA/.