United States Average Monthly or Annual Precipitation, 1971 - 2000

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Frequently-anticipated questions:

What does this data set describe?

United States Average Monthly or Annual Precipitation, 1971 - 2000
This data set contains spatially gridded average monthly and annual precipitation for the climatological period 1971-2000. Distribution of the point measurements to a spatial grid was accomplished using the PRISM model, developed and applied by Chris Daly of the PRISM Climate Group at Oregon State University.
There are many methods of interpolating climate from monitoring stations to grid points. Some provide estimates of acceptable accuracy in flat terrain, but few have been able to adequately explain the extreme, complex variations in climate that occur in mountainous regions. Significant progress in this area has been achieved through the development of PRISM (Parameter-elevation Regressions on Independent Slopes Model). PRISM is an analytical model that uses point data and an underlying grid such as a digital elevation model (DEM) or a 30 yr climatological average (e.g. 1971- 2000 average) to generate gridded estimates of monthly and annual precipitation and temperature (as well as other climatic parameters). PRISM is well suited to regions with mountainous terrain, because it incorporates a conceptual framework that addresses the spatial scale and pattern of orographic processes. Grids were modeled on a monthly basis. Annual grids of temperature are produced by averaging the monthly grids, and summing for precipitation.
  1. How should this data set be cited?

    The PRISM Climate Group at Oregon State University., 20061206, United States Average Monthly or Annual Precipitation, 1971 - 2000: The PRISM Climate Group at Oregon State University., Corvallis, Oregon, USA.

    Online Links:

    • \\gisimage\images\LandcovMaint\NewRasterData\Precipitation\kc_precip_in

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.772109
    East_Bounding_Coordinate: -120.856334
    North_Bounding_Coordinate: 48.163279
    South_Bounding_Coordinate: 46.893120

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 01-Jan-1997
    Ending_Date: 31-Dec-2000
    Climatological period from which the point observations were taken

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 183 x 187 x 1, type Grid Cell

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 47.500000
      Standard_Parallel: 48.733333
      Longitude_of_Central_Meridian: -120.833333
      Latitude_of_Projection_Origin: 47.000000
      False_Easting: 1640416.666667
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2500.000000
      Ordinates (y-coordinates) are specified to the nearest 2500.000000
      Planar coordinates are specified in survey feet

      The horizontal datum used is D_North_American_1983_HARN.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    average precipitation grid cell value
    ASCII values (Source: Self-evident)

    spatially gridded average precipitation values (Source: Daly, C., W. P. Gibson, G.H. Taylor, G. L. Johnson, P. Pasteris. 2002. A knowledge-based approach to the statistical mapping of climate. Climate Research, 22, 99-113, 2002)

    Range of values
    Units:Millimeters times 100 (converted to inches)

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Wayne Gibson
    2001 Kelley Engineering Cen
    Corvallis, Oregon 97331-2209

    (541) 737-2531 (voice)

Why was the data set created?

Display and/or analyses requiring spatially distributed monthly or annual precipitation for the climatological period 1971-2000.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    Accuracy of this data set is based on the original specification of the Defense Mapping Agency (DMA) 1 degree digital elevation models (DEM). The stated accuracy of the original DEMs are 130 m circular error with 90% probability.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Point estimates of precipitation originated from some or all of the following sources: 1) National Weather Service (NWS) Cooperative (COOP) stations, 2) Natural Resources Conservation Service (NRCS) SNOTEL, 3) United States Forest Service (USFS) and Bureau of Land Management (BLM) RAWS Stations, 4) Bureau of Reclemation (AGRIMET) stations, 5) California Data Exchange Center (CDEC) stations, 6) Storage guages, 7) NRCS Snowcourse stations, 8) Other State and local station networks, 9) Estimated station data, 0) Canadian stations, 10) Upper air stations, and 11) NWS/Federal Aviation Administration (FAA) Automated surface observation stations (ASOS). All COOP station data were subjected to quality control checks by the National Climatic Data Center (NCDC). All COOP, SNOTEL and other data were subjected to further quality control checks by the PRISM Climate Group.

  5. How consistent are the relationships among the observations, including topology?

    All data were based on the same averaging period (1971-2000). Similar quality assurance procedures were used with all input data sets.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: Access pursuant to license agreement
Acknowledgement of the following agencies in products derived from these data: The PRISM Climate Group at Oregon State University.

  1. Who distributes the data set? (Distributor 1 of 1)

    Wayne Gibson
    PRISM Climate Group
    2011 Kelley Engineering
    Corvallis, OR 97331

    (541) 737-2531 (voice)

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    This digital data set publication was prepared by the PRISM Climate Group. Neither the PRISM Climate Group nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or misuse of the data, or for damage, transmission of viruses or computer contamination through the distribution of these data sets or for the usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the PRISM Climate Group or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the PRISM Climate Group or any agency thereof. Standard_Order_Process:

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 25-Oct-2011
Metadata author:
The PRISM Climate Group, OSU
c/o Wayne Gibson
2011 Kelley Engineering Center
Corvallis, OR 97331

(541) 737-2531 (voice)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.6 on Wed Apr 10 12:34:39 2013