Identification_Information:

  Citation:
    Citation_Information:
      Originator: NOAA/National Weather Service/Office of Hydrologic Development/Hydrometeorological Design Studies Center (HDSC)
      Publication_Date: 20011205
      Title:
        NOAA Atlas 2 - Precipitation-Frequency Atlas for the
        Western United States All-season series
      Edition: first
      Geospatial_Data_Presentation_Form: Map/Atlas
      Publication_Information:
        Publication_Place: Silver Spring, MD, USA
        Publisher: NOAA/National Weather Service
      Other_Citation_Details: none.
      Online_Linkage: <URL:http://www.nws.noaa.gov/oh/hdsc/>

  Description:
    Abstract:
      NOAA Atlas 2 is divided into 11 volumes, one for each of the 11
      Western states and contains precipitation-frequency maps for 6-hour and
      24-hour return Periods from 2 to 100 years. However, only a subset of
      these maps have been converted into GIS rasters. The digitizing of the
      NOAA Atlas 2 data sets was begun for the specific purpose of performing
      the storm studies used in the development of Hydrometeorological Report (HMR)
      55A, HMR 57 and the analysis of parameters used in the development of probable
      maximum precipitation (PMP) in these reports. The digitizing and processing of
      these files occurred at the Bureau of Reclamation in Denver, Colorado. Richard
      Stodt was the project leader and conducted a large portion of the work. The
      NWS had the opportunity to see the work as it progressed beyond the QC stage and
      make suggestions or note corrections that might have been needed. The NWS and
      the Bureau of Reclamation were essentially operating as an integrated team with
      tasks allocated according to which office had the appropriate resources to
      complete them with NWS having final say on technical matters. More
      detailed info can be found in the minutes of the 'Interagency
      Hydrometeorological Study Team' meetings between 1984-1988. With the
      permission of the Bureau of Reclamation, we are posting these rasters as
      part of our growing on-line spatial database.
    Purpose:
      With the growing use of geographic information systems (GIS) and the
      the continued need of precipitation frequency data for design criteria,
      these GIS rasters have been produced. Originally however, the digitizing
      of the NOAA Atlas 2 data sets was begun for the specific purpose of
      performing the storm studies used in the development of HMR 55A, HMR 57
      and the analysis of parameters used in the development of PMP in these
      reports.
  Time_Period_of_Content:
    Time_Period_Information:
      Range_of_Dates/Times:
        Beginning_Date: 1897
        Ending_Date: 1970
    Currentness_Reference:
      Climatological period from which the point precipitation observations were
      taken.
  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: As needed
  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: -124.897916667
      East_Bounding_Coordinate: -101.818750000
      North_Bounding_Coordinate: 49.2270833333
      South_Bounding_Coordinate: 31.0979166667
  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: None
      Theme_Keyword: 100-year precipitation
      Theme_Keyword: atlas
      Theme_Keyword: all-season
      Theme_Keyword: design criteria
      Theme_Keyword: frequencies
      Theme_Keyword: hydrometeorology
      Theme_Keyword: meteorology
      Theme_Keyword: NOAA Atlas 2
      Theme_Keyword: precipitation
      Theme_Keyword: precipitation frequency
      Theme_Keyword: raster data
      Theme_Keyword: climatology
      Theme_Keyword: extreme precipitation
      Theme_Keyword: maps
      Theme_Keyword: GIS
      Theme_Keyword: Geographical Information System
    Place:
      Place_Keyword_Thesaurus: None
      Place_Keyword: Arizona
      Place_Keyword: California
      Place_Keyword: Nevada
      Place_Keyword: New Mexico
      Place_Keyword: Western United States
      Place_Keyword: Colorado
      Place_Keyword: Wyoming
      Place_Keyword: Montana
      Place_Keyword: Oregon
      Place_Keyword: Washington
      Place_Keyword: Idaho
      Place_Keyword: Utah
  Access_Constraints: n/a, no restrictions apply and data is public domain
  Use_Constraints:
    Acknowledgement of NOAA/National Weather Service/Office of Hydrologic Development/Hydrometeorological Design Studies Center (HDSC) and the
    Bureau of Reclamation.
  Point_of_Contact:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: NOAA/National Weather Service/Office of Hydrologic Development/Hydrometeorological Design Studies Center (HDSC)
        Contact_Person: 
      Contact_Position: 
      Contact_Address:
        Address_Type: mailing and physical address
        Address:
          Office of Hydrologic Development, National Weather Service W/OHD13,
          1325 East-West Highway
        City: Silver Spring
        State_or_Province: MD
        Postal_Code: 20910
        Country: U.S.A.
      Contact_Voice_Telephone: (301) 713-0640
      Contact_Facsimile_Telephone: (301) 713-0963
      Contact_Electronic_Mail_Address: hdsc.questions@noaa.gov
      Hours_of_Service: 8 a.m. to 5 p.m. Eastern, Monday-Friday
  Native_Data_Set_Environment:
    Red Hat Linux version 7.2, GRASS GIS (Geographic Resources
    Analysis Support System) version 4.2.1

Data_Quality_Information:

  Attribute_Accuracy:
    Attribute_Accuracy_Report:
      All attributes created during the digitization process were
      tested for internal consistency. In addition, thorough
      comparisons where conducted with hardcopy NOAA Atlas 2 maps.
      In fact, each file of digitized vectors was plotted at 1:1,000,000
      scale and overlaid on the master NOAA Atlas 2 map.  For the whole
      project several hundred of these check plots were produced.  Labels
      were compared and corrected if necessary. If the x-y position of
      points along a line were out of place, the appropriate x-y corrections
      were computed and applied or if it was not correctable the line was
      re-digitized. Once satisfied with an accurate digitized vector data
      set, the maps were composited for the digitized files for the NOAA
      Atlas 2 map being processed. The resutling grid was contoured using
      the Surface II contouring program. This was overlaid on the
      NOAA Atlas 2 map being digitized and checked for discrepancies.
      Occasionally an error would be discovered that slipped through the
      initial QC process.  It would be corrected and appropriate new check
      maps would be created until the map was considered to be free of errors.
  Logical_Consistency_Report:
    All data were based on precipitation-reporting stations
    that had at least 20 years of daily or hourly precipitation
    data between 1897 and 1970. Similar quality assurance
    procedures were used with all input data sets.
  Completeness_Report:
    Point precipitation values originated from the following sources:
    1) National Weather Service Cooperative (COOP) stations, 2) Natural
    Resources Conservation Service (NRCS) SNOTEL, NWS First Order hourly and daily
    stations. All NWS station data were subjected to quality control checks by
    the National Climatic Data Center (NCDC) and the Bureau of Reclamation.
  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report: Positional accuracy has not been determined.

  Lineage:
    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: National Climatic Data Center
          Publication_Date: 1970
          Title: Precipitation Data, Hourly
          Publication_Information:
            Publication_Place: Asheville, NC, USA
            Publisher: National Climatic Data Center
          Online_Linkage: <URL:http://lwf.ncdc.noaa.gov/oa/ncdc.html>
      Type_of_Source_Media: digital files
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Range_of_Dates/Times:
            Beginning_Date: 1897
            Ending_Date: 1970
        Source_Currentness_Reference: ground condition
      Source_Citation_Abbreviation: TD3240
      Source_Contribution:
        Location and values of known hourly precipitation
        amounts.

    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: National Climatic Data Center
          Publication_Date: 1970
          Title: Daily Cooperative Summary of the Day
          Publication_Information:
            Publication_Place: Asheville, NC, USA
            Publisher: National Climatic Data Center
          Online_Linkage: <URL:http://lwf.ncdc.noaa.gov/oa/ncdc.html>
      Type_of_Source_Media: digital files
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Range_of_Dates/Times:
            Beginning_Date: 1897
            Ending_Date: 1970
        Source_Currentness_Reference: ground condition
      Source_Citation_Abbreviation: TD3200
      Source_Contribution:
        Location and values of known daily precipitation amounts at National
        Weather Service Cooperative observer sites.

    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: National Climatic Data Center
          Publication_Date: 1970
          Title: First Order Summary of the Day
          Publication_Information:
            Publication_Place: Asheville, NC, USA
            Publisher: National Climatic Data Center
          Online_Linkage: <URL:http://lwf.ncdc.noaa.gov/oa/ncdc.html>
      Type_of_Source_Media: digital files
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Range_of_Dates/Times:
            Beginning_Date: 1897
            Ending_Date: 1970
        Source_Currentness_Reference: ground condition
      Source_Citation_Abbreviation: TD3210
      Source_Contribution:
        Location and values of known hourly and daily precipitation amounts at
        National Weather Service First Order stations.

    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: Natural Resources Conservation Service (NRCS)
          Publication_Date: 1970
          Title:
            Cooperative Snow Survey Data of Federal - State - Private
            Cooperative Snow Surveys
          Publication_Information:
            Publication_Place: Portland, Oregon, USA
            Publisher:
              Natural Resources Conservation Service, Water and Climate
              Center
          Online_Linkage: <URL:http://www.wcc.nrcs.usda.gov/>
      Type_of_Source_Media: digital files, paper reports, online
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Range_of_Dates/Times:
            Beginning_Date: 1940
            Ending_Date: 1970
        Source_Currentness_Reference: ground condition
      Source_Citation_Abbreviation: SNOTEL (SNOwpack TELemetry)
      Source_Contribution: Location and values of known daily precipitation.

    Process_Step:
      Process_Description:
        It is beyond the scope of this metadata to document the processes
        involved in generating the NOAA Atlas 2 precipitation frequency
        contours. However, the processes are documented in the NOAA Atlas 2
        report which is available from HDSC at
        <URL:http://www.nws.noaa.gov/oh/hdsc/studies/prcpfreq.html>
      Process_Date: 197401
    Process_Step:
      Process_Description: The NOAA Atlas 2 hardcopy maps were hand-digitized.
      Process_Date: 198401
    Process_Step:
      Process_Description:
        The contour lines and their attribute labels were
        quality checked.
      Process_Date: 198501
    Process_Step:
      Process_Description: The contour lines were converted into GRASS GIS binary vector files.
      Process_Date: 200111
    Process_Step:
      Process_Description:
        The GRASS binary vector files were then converted into raster-lines,
        using the GRASS command, v.to.rast. Thereafter, the command
        r.surf.contour was used to interpolate between the raster lines and
        produce the final rasters.
      Process_Date: 200011

Spatial_Data_Organization_Information:

  Direct_Spatial_Reference_Method: Raster
  Raster_Object_Information:
    Raster_Object_Type: Grid Cell
    Row_Count: 4351
    Column_Count: 5539

Spatial_Reference_Information:

  Horizontal_Coordinate_System_Definition:
    Geographic:
      Latitude_Resolution: 0.0041666667
      Longitude_Resolution: 0.0041666667
      Geographic_Coordinate_Units: Decimal Degrees
    Geodetic_Model:
      Horizontal_Datum_Name: North American Datum of 1927 (NAD27)
      Ellipsoid_Name: Clarke 1866
      Semi-major_Axis: 6378206.4
      Denominator_of_Flattening_Ratio: 294.98

Entity_and_Attribute_Information:

  Detailed_Description:
    Entity_Type:
      Entity_Type_Label: precipitation frequency grid cell value
      Entity_Type_Definition: ASCII values
      Entity_Type_Definition_Source: Self-evident
    Attribute:
      Attribute_Label: precipitation frequency grid cell value
      Attribute_Definition: spatially gridded precipitation frequency estimates
      Attribute_Definition_Source:
        Miller, J.F., R.H. Frederick, and R.J. Tracy, 1973. Precipitation-frequency atlas of the western United States, NOAA Atlas 2, 11 vols., National Weather Service,
        Silver Spring, MD.
      Attribute_Domain_Values:
        Range_Domain:
          Range_Domain_Minimum: 45000
          Range_Domain_Maximum: 2400000
          Attribute_Units_of_Measure: in * 100000
          Attribute_Measurement_Resolution: 1
        Enumerated_Domain:
          Enumerated_Domain_Value: -9999
          Enumerated_Domain_Value_Definition: no data available or outside of range domain
          Enumerated_Domain_Value_Definition_Source: NOAA Atlas 2 Precipitation Frequency Study

Distribution_Information:

  Distributor:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: National Weather Service/Office of Hydrologic Development/Hydrometeorological Design Studies Center (HDSC)
        Contact_Person: 
      Contact_Address:
        Address_Type: mailing and physical address
        Address:
          Office of Hydrologic Development, National Weather Service W/OHD13,
          1325 East-West Highway
        City: Silver Spring
        State_or_Province: MD
        Postal_Code: 20910
        Country: U.S.A.
      Contact_Voice_Telephone: (301) 713-0640 
      Contact_Facsimile_Telephone: (301) 713-0963
      Contact_Electronic_Mail_Address: hdsc.questions@noaa.gov
      Hours_of_Service: 8 a.m. to 5 p.m. Eastern, Monday-Friday
  Resource_Description:
    These rasters were originally developed for the specific purpose of
    performing the storm studies used in the development of HMR 55A, HMR
    57 and the analysis of parameters used in the development of probable
    maximum precipitation (PMP) in these reports.
  Distribution_Liability: Users must assume responsibility to determine the appropriate use of these data.
  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name: ARC/INFO ASCII Grid
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: <URL:http://hdsc.nws.noaa.gov/>
    Fees: none

Metadata_Reference_Information:

  Metadata_Date: 20030425
  Metadata_Review_Date: 20030425
  Metadata_Contact:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: National Weather Service/Office of Hydrologic Development/Hydrometeorological Design Studies Center (HDSC)
        Contact_Person: 
      Contact_Position: 
      Contact_Address:
        Address_Type: Mailing and physical address
        Address:
          Office of Hydrologic Development, National Weather Service W/OHD13,
          1325 East-West Highway
        City: Silver Spring
        State_or_Province: MD
        Postal_Code: 20910
        Country: U.S.A.
      Contact_Voice_Telephone: (301) 713-0640
      Contact_Facsimile_Telephone: (301) 713-0963
      Contact_Electronic_Mail_Address: hdsc.questions@noaa.gov
      Hours_of_Service: 8 a.m. to 5 p.m. Eastern, Monday-Friday
  Metadata_Standard_Name: FGDC CSDGM
  Metadata_Standard_Version: FGDC-STD-001-1998