National Oceanic and Atmospheric Administration (NOAA) Forecast Systems Laboratory (FSL) Meteorological Assimilation Data Ingest System (MADIS) Data

1.0 General Description

This dataset is a collection of data from many networks. The data are fed to the National Center for Atmospheric Research / Earth Observing Laboratory (NCAR/EOL) over the LDM by the FSL Meteorological Assimilation Data Ingest System (MADIS). Some of these networks are themselves collections of data from unrelated sources. Each of these networks/subnetworks can contain different frequency data and different parameters. NCAR/EOL converts all of this data to NCAR/EOL Surface QC format. The "Nominal" hourly observations for the NAME domain and time period are included in the dataset "FSL MADIS Hourly Data (NCAR/EOL surface QC format) [NCAR/EOL]. Special records are located in the dataset "FSL MADIS Specials Data (NCAR/EOL surface QC format) [NCAR/EOL]". This documentation applies to both.

2.0 Detailed Data Description

The hourly parameter value given in the hourly dataset is the value closest to the hour that falls at or after :45 minutes and before (but not at) 15 minutes after the hour. MADIS QC flags are not carried forward to NCAR/EOL surface QC format. However, the MADIS QC summary value X "Failed QC stage 1", which is a gross limit check, has been used to mask out extremely bad data. If the data fails this check, it is set to missing. Precipitation data is not included in this data.

2.1 Detailed Format Description

    Parameters                              Units
    ----------                              -----
    Date of Observation                     UTC Nominal
    Time of Observation                     UTC Nominal
    Date of Observation                     UTC Actual
    Time of Observation                     UTC Actual
    Network Identifier                      Abbreviation of platform name
    Station Identifier                      Network Dependent
    Latitude                                Decimal degrees, South is negative
    Longitude                               Decimal degrees, West is negative
    Station Occurrence                      Unitless
    Station Elevation                       Meters
    Station Pressure, QC flag               Hectopascals (mb)
    Reported Sea Level Pressure, QC flag    Hectopascals (mb)
    Computed Sea Level Pressure, QC flag    Hectopascals (mb)
    Dry Bulb Temperature, QC flag           Celsius
    Dew Point, QC flag                      Celsius
    Wind Speed, QC flag                     m/s
    Wind Direction, QC flag                 Degrees
    Total Precipitation, QC flag            mm
    Squall/Gust Indicator                   Code Value
    Squall/Gust Value, QC flag              m/s
    Present Weather, QC flag                Code Value
    Visibility, QC flag                     Meters
    Ceiling Height (first layer)            Hundreds of feet
    Ceiling Flag (first layer), QC flag     Code Value
    Cloud Amount (first layer), QC flag     Code Value
    Ceiling Height (second layer)           Hundreds of feet
    Ceiling Flag (second layer), QC flag    Code Value
    Cloud Amount (second layer), QC flag    Code Value
    Ceiling Height (third layer)            Hundreds of feet
    Ceiling Flag (third layer), QC flag     Code Value
    Cloud Amount (third layer), QC flag     Code Value

The list of code values for the Present Weather is too large to reproduce in this document. Refer to WMO, 1988 for a complete list of Present Weather codes.

The code values for the Squall/Gust Indicator are:

    Code      Definition
    ----      ----------
    blank     No Squall or Gust
    S         Squall
    G         Gust

    Code      Definition
    ----      ----------
     0         None
     1         Thin
     2         Clear below 12,000 feet
     3         Estimated
     4         Measured
     5         Indefinite
     6         Balloon
     7         Aircraft
     8         Measured/Variable
     9         Clear below 6,000 feet (AUTOB)
     10        Estimated / Variable
     11        Indefinite / Variable
     12        12-14 reserved
     15        Missing

     Code      Definition
     ----      ----------
     0         0 ( or clear)
     1         1 okta or less, but not zero or 1/10 or less, but not zero
     2         2 oktas or 2/10-3/10
     3         3 oktas or 4/10
     4         4 oktas or 5/10
     5         5 oktas or 6/10
     6         6 oktas or 7/10-8/10
     7         7 oktas or more, but no 8 oktas or 9/10 or more, but not 10/10
     8         8 oktas or 10/10 (or overcast)
     9         Sky obscured by fog and/or other meteorological phenomena
     10        Sky partially obscured by fog and/or other meteorological
                phenomena
     11        Scattered
     12        Broken
     13        13-14 Reserved
     15        Cloud cover is indiscernible for reasons other than fog or
               other meteorological phenomena, or observation is not made.

Sea Level Pressure is calculated from station pressure using standard GEMPAK algorithms (Unidata, 2003).

When not present in the raw data, the dewpoint temperature was computed by UCAR/JOSS from temperature and relative humidity using the formula from Bolton (1980).

When not present in the raw data, station pressure is computed by UCAR/JOSS from altimeter and elevation using the formula from the Smithsonian Meteorological Tables, 1949.

3.0 Quality Control Processing

     QC Code   Description
     -------   -----------
     U         Unchecked
     M         Normally recorded but missing.