MADIS Surface Variables - SAO - Numeric
-------------------------------------------------------------------------------------
Code       Name                                Units      Max    Notes     Database
                                                       QC Level          FSL    AWIPS*
-------------------------------------------------------------------------------------
TD        dewpoint temperature                 K            3    1,6      X
RH        relative humidity                    %            3    1,6      X
Q         specific humidity                    kg/kg        3    1,6      X
DPD       dewpoint depression                  K            3    1,6      X
AH        absolute humidity                    g/(m**3)     3    1,6      X
ALTSE     altimeter                            Pa           3    2        X
WVMR      water vapor mixing ratio             kg/kg        3    1,6      X
PT3       3 hour pressure change               Pa           2    3        X
PT3CHR    character of 3h pressure change      code         0    3        X
SLP       sea level pressure                   Pa           3             X
P         station pressure                     Pa           3    2        X
T         air temperature                      K            3    4        X
TV        virtual temperature                  K            3    4,6      X
DD        wind direction                       deg          3    5        X
FF        wind speed                           m/s          3    5        X
U         u wind component                     m/s          3    5        X
V         v wind component                     m/s          3    5        X
VIS       visibility                           m            1             X
ELEV      elevation                            m            0             X
LAT       latitude                             deg N        0             X
LON       longitude                            deg E        0             X
CORR      correction flag                      code         0             X
PCP1H     accumulated precip - 1h              m            1    7,6      X
PCP3H     accumulated precip - 3h              m            1             X
PCP6H     accumulated precip - 6h              m            1             X
PCP24H    accumulated precip - 24h             m            1    6        X
PCPRATE   precipitation rate                   kg/(m**2)/s  1    7        X
SKYCVLB   sky cover layer base                 m            0    10       X
T24MIN    24 hour minimum temperature          K            1    6        X
T24MAX    24 hour maximum temperature          K            1    6        X
FFGUST    wind gust                            m/s          2    6        X
NOBSSC    number of sky cover obs                                         X


MADIS Surface Variables - SAO - Character
-------------------------------------------------------------------------------------
Code       Name                                Character         Notes     Database
                                               Size                      FSL    AWIPS*
-------------------------------------------------------------------------------------
SKYCOV    sky cover                            6x8               10       X       
AUTOTYP   automated station type               6                 18       X
REPTYPE   report type                          6                 19       X


Notes (for all surface datasets)
--------------------------------

1.  Dewpoint temperature and/or relative humidity are the moisture variables 
    stored in the database.  The user can select either of these variables, or 
    select dewpoint depression, specific humidity, absolute humidity, or water 
    vapor mixing ratio which will then be calculated by the MADIS API.  If 
    available, the stage 3 QC results from the dewpoint variable will be used 
    for any of the calculated variables.  If this isn't available, the QC 
    results from the stored RH variable will be used.  Also note that pressure 
    is needed for the absolute humidity conversion; for the COOP dataset this is 
    done by using the U.S. Standard Atmosphere calculation to calculate pressure 
    from station elevation.

2.  As altimeter and station pressure can be calculated from each
    other, for datasets without altimeter (MARITIME) the altimeter
    will be calculated by the MADIS API, and for datasets without
    station pressure (METAR, SAO, High Frequency METAR) that variable
    will be calculated as well.  With the MESONET dataset, if the
    stored variable isn't the one requested by the user for each
    particular station, the calculated value will be returned.  In all
    cases, the stage 3 QC from the altimeter variable (if available)
    will be applied.

3.  The 3 hour pressure change value consists of the numeric pressure change 
    value, with a sign applied per the value in the character of 3h pressure 
    change variable.  The latter variable is coded:

       Value      Meaning
       -----      -------
         0        pressure same or higher than 3 hours ago
         1        increasing then steady
         2        increasing
         3        decreasing or steady, then increasing
         4        steady
         5        pressure same or lower than 3 hours ago
         6        decreasing
         7        steady or increasing, then decreasing

4.  Air temperature is the temperature variable stored in the database.  The user
    can optionally select virtual temperature, which will then be calculated by 
    the MADIS API.  The QC results from air temperature will apply in either 
    case.  Also note that if virtual temperature cannot be calculated (missing 
    or bad dewpoint or pressure), and the air temperature passed all QC checks, 
    the air temperature will be returned instead, and a QC data descriptor value
    of "T" will be assigned.  As with the absolute humidity conversion mentioned
    above, the virtual temperature conversion done for the COOP dataset uses
    pressure calculated from the station elevation.

5.  Wind speed and direction are reported and stored in the database.  The user 
    can optionally select u & v wind components and those will be calculated and 
    returned.  The QC results from speed and direction will be used In either 
    case, and if one of the map projections has been selected via the MSETDOM call, 
    the winds will be rotated to match the projection.

    The documentation in the COOP cdl was changed to remove the height of the 
    anemometer.  All anemometers are at 10 meters heights except for (GYX, TANM3, 
    and STYN6) which are at 3 meters.

6.  Data platform type (MARITIME):

       Value      Meaning
       -----      -------
         0        stationary (moored buoy or CMAN)
         1        moving (drifting buoy or ship)

    Data platform type (High Frequency METAR):

       Value      Meaning
       -----      -------
         1        Federal ASOS
         2        Federal AWOS
         3        Federal AOS
         4        Non-fed ASOS
         5        Non-fed AWOS
         6        Non-fed AOS

    Data platform type (COOP):

       Value      Meaning
       -----      -------
       < 100      Phase II site (regional hub)
        100       Phase II site (GOES/HADS)
        200       Phase I site (direct connect)
        300       Phase I site (GOES/HADS)

    The modernized NWS Cooperative Observer sites can provide different 
    variables, and on different schedules, dependent both on the type of site
    (Phase I or II) and on the processing done as part of reformatting
    the data sent over the various communications systems in use.  Here are
    the primary differences:

    - Phase I sites only report a single temperature observation per hour, 
      valid at minute 0.

    - Phase II GOES/HADS sites only report once per hour, but the reports
      contain 5-minute observations from the last hour.
   
    9/26/06: The Phase II GOES/HADS sites are being phased out, as part of
    an upgrade where the COOP network has been gradually rolling in a new
    software load over the last several months (and it's not done yet).
    The new load is indicated in MADIS as data platform types 2-99 (currently
    only 2 is in use).  This upgrade has changed what variables are available from 
    the Phase II stations.
    
    Variables that are no longer available for COOP PLATTYP 2 stations:

         TD1H      hourly average dewpoint temperature  
         RH        relative humidity                    
         RH1H      hourly average relative humidity     
         Q         specific humidity                    
         Q1H       hourly average specific humidity     
         DPD       dewpoint depression                  
         DPD1H     hourly average dewpoint depression   
         AH        absolute humidity                    
         AH1H      hourly average absolute humidity     
         WVMR      water vapor mixing ratio             
         TV        virtual temperature
         T1H       hourly average temperature           
         TV1H      hourly average virtual temperature   
         DD1H      hourly average wind direction        
         DD24H     daily average wind direction         
         FF1H      hourly average wind speed            
         FF24H     daily average wind speed             
         U1H       hourly average u wind component      
         U24H      daily average u wind component       
         V1H       hourly average v wind component      
         V24H      daily average v wind component       
         PCPTOTL   total precipitation                  
         PCP1H     accumulated precip - 1h              
         PCP24H    accumulated precip - 24h             
         PCPUDAY   accum. precip - user-defined day     
         UDSTART   user-defined day start HHMM          
         PCPRATE   precipitation rate                   
         T24MIN    24 hour minimum temperature          
         T24MAX    24 hour maximum temperature          
         SOILM2    soil moisture percent - 2 inch       
         SOILM4    soil moisture percent - 4 inch       
         SOILM8    soil moisture percent - 8 inch       
         SOILM20   soil moisture percent - 20 inch      
         SOILM40   soil moisture percent - 40 inch      
         SOILT2    soil temperature - 2 inch            
         SOILT4    soil temperature - 4 inch            
         SOILT8    soil temperature - 8 inch            
         SOILT20   soil temperature - 20 inch           
         SOILT40   soil temperature - 40 inch           
         DDMAX1H   wind dir at hourly max wind speed    
         FFMAX1H   hourly maximum wind speed            
         GSRD5M    global solar radiation - 5min        
         STNSPC1   station specific #1                  
         STNSPC2   station specific #2                  
         T24MINT   time of 24 hour minimum temperature  
         T24MAXT   time of 24 hour maximum temperature  

    Variables that have been added for COOP PLATTYP 2 stations:

         DDGUST    wind dir at gust  (5m)
         FFGUST    wind gust         (5m)
         PCP5M     accumulated precip - 5m              

7.  The user can select either accumulated precip - 1h or precipitation rate.  
    Whichever variable is actually stored in the MADIS database will be converted
    to the form desired by the caller.

8.  Precipitation intensity (MESONET):

       Value      Meaning
       -----      -------
         0        intensity info not available
         1        none
         2        light
         3        moderate
         4        heavy
         5        slight
         6        other

    Stations measuring precipitation type and intensity may take observations
    with one or two sensors.  Therefore, an array of 2 elements will be
    returned for each record, and the caller should dimension the array to
    (2,200000).

9.  Precipitation type (MESONET):

       Value      Meaning
       -----      -------
         0        no precipitation
         1        precipitation present but unclassified
         2        rain
         3        snow
         4        mixed rain and snow
         5        light
         6        light freezing
         7        freezing rain
         8        sleet
         9        hail
        10        other
        11        unidentified
        12        unknown
        13        frozen
        14        ice pellets
        15        recent
        29        RPU-to-maxSensor communications failure
        30        sensor failure

    Stations measuring precipitation type and intensity may take observations
    with one or two sensors.  Therefore, an array of 2 elements will be
    returned for each record, and the caller should dimension the array to
    (2,200000).

10. The sky cover variables (METAR, SAO, MESONET, High Frequency METAR) 
    can have up to 6 different layers (array elements) for each record.  
    The "sky cover layer base" variable is a number, so it should be 
    dimensioned to (6,200000) by the caller.  The character "sky cover" 
    variable gives information about each layer reported in the sky cover 
    layer base variable, and has 8 characters for each of the 6 layers, so
    it should be dimensioned character*8 skycover(6,200000).  Note that
    the High Frequency METAR dataset can only go up to 3 layers, and the SAO
    dataset has a maximum of 5 layers, but to allow for mixing this data with 
    the other surface providers 6 layers (the last ones missing) will be 
    returned.

    For more information on these variables, see section 9.4.2 of Federal
    Meteorological Handbook 1 (FMH-1).  A PDF version of FMH-1 is available
    at http://www.ofcm.gov/fmh-1/fmh1.htm.

    Sky cover values:

       Value      Meaning               Summation amount of layer
       -----      -------               -------------------------
       VV         Vertical Visibility   8/8
       SKC or CLR Clear                 0
       FEW        Few                   1/8 - 2/8
       SCT        Scattered             3/8 - 4/8
       BKN        Broken                5/8 - 7/8
       OVC        Overcast              8/8

       1.  CLR is used at automated stations when no layers at or below 12,000 ft
           are reported; SKC is used at manual stations when no layers are 
           reported.

       2.  Any layer amount less than 1/8 is reported as FEW.

11. Height of the lowest cloud layer (MARITIME):

       Value      Meaning
       -----      -------
         0        0 to 100 ft
         1        200 to 300 ft
         2        400 to 600 ft
         3        700 to 900 ft
         4        1000 to 1900 ft
         5        2000 to 3200 ft
         6        3300 to 4900 ft
         7        5000 to 6500 ft
         8        7000 to 8000 ft
         9        8500 or higher or no clouds
        -1        unknown or cloud base below surface of station

12. Low level cloud type (MARITIME):

       Value      Meaning
       -----      -------
         0        no Cu, Cb, Sc, or St
         1        Cu w/ little vertical extent
         2        Cu w/ moderate or great vertical extent
         3        Cb w/out fibrous or striated upper part
         4        Sc formed by spreading Cu
         5        Sc not formed by spreading Cu
         6        St or ragged St
         7        ragged St or ragged Cu
         8        Cu and Sc w/ bases at different levels
         9        Cb w/ fibrous or striated upper part
        -1        low clouds not visible (obscured)

13. Middle level cloud type (MARITIME):

       Value      Meaning
       -----      -------
         0        no Ac, As, or Ns
         1        semi-transparent As
         2        opaque As, or Ns
         3        semi-transparent Ac predominant
         4        Ac continually changing in appearance
         5        Ac invading the sky
         6        Ac formed by spreading of Cu or Cb
         7        double layered Ac or thick Ac; or Ac & As
         8        turreted Ac or Ac in tufts
         9        Ac of a chaotic sky
        -1        middle clouds not visible (obscured)

14. High level cloud type (MARITIME):

       Value      Meaning
       -----      -------
         0        no Ci, Cs, or Cc
         1        Ci in filaments or hooks
         2        dense Ci & turreted Ci & Ci in tufts
         3        dense Ci orig from Cb, present
         4        Ci invading the sky
         5        Cs not exceeding 45 degrees altitude
         6        Cs exceeding 45 degrees altitude
         7        Cs covering the whole sky
         8        Cs not invading the sky
         9        Cc alone, or Cc more than (Ci & Cs)
        -1        high clouds not visible (obscured)

15. Tide indicator (MARITIME):

       Value      Meaning
       -----      -------
         0        Data not available
         1        Low tide, observed tide below predicted level
         2        Low tide, observed tide same as predicted level
         3        Low tide, observed tide above predicted level
         4        Neither low nor high tide, observed tide below predicted level
         5        Neither low nor high tide, observed tide same as predicted level
         6        Neither low nor high tide, observed tide above predicted level
         7        High tide, observed tide below predicted level
         8        High tide, observed tide same as predicted level
         9        High tide, observed tide above predicted level

16. The dewpoint & temperature from tenths of a deg C variables (METAR) are 
    decoded from the remarks section of the raw reports, for designated stations 
    only, and have values rounded to the nearest 0.1 degree C.  The primary 
    temperature and dewpoint variables are reported from all stations, and in 
    the raw reports, are rounded to the nearest whole degree C.

17. Road state (MESONET):

       Value      Meaning
       -----      -------
         0        No report
         1        Dry
         2        Moist
         3        Moist and chemically treated
         4        Wet
         5        Wet and chemically treated
         6        Ice
         7        Frost
         8        Snow
         9        Snow/Ice watch
        10        Snow/Ice warning
        11        Wet above freezing
        12        Wet below freezing
        13        Absorption
        14        Absorption at dewpoint
        15        Dew
        16        Black ice warning
        17        Other
        18        Slush

18. Automated station type (METAR, SAO):

       Value      Meaning
       -----      -------
        AO1       automated station without precipitation discriminator (METAR)
        AO2       automated station with precipitation discriminator (METAR)
        AUTO2     automated station (SAO)
        AUTO4     automated station (SAO)
        AUTO7     automated station (SAO)
        AUTO8     automated station (SAO)
        blank     manual station

19. Report type (METAR, SAO):

       Value      Meaning
       -----      -------
       METAR      scheduled report (METAR)
       SPECI      report triggered by SPECI criteria (METAR) (see FMH-1)
       SA         scheduled report (SAO)

20. The coded values for the present weather variable (METAR,
    MARITIME, MESONET, High Frequency METAR) are too extensive to list
    in this document.  See FMH-1, particularly section 12.6.8.  A PDF
    version of FMH-1 is available at
    http://www.ofcm.gov/fmh-1/fmh1.htm.

    The coded values for the COOP present weather variable are listed below:

       Value      Meaning
       -----      -------
        -         No report
        FG        Fog
        IE        Ice
        GL        Glaze
        TS        Thunder
        GR        Hail
        DW        Damaging Winds
        RA        Rainy
        SN        Snowy


21. The station location (METAR, MESONET, COOP) generally contains a geographic 
    description of the station's location, typically including the city, state, 
    and sometimes the country.

    With the MESONET dataset, in addition, characters (40:50) are used to denote
    the "subprovider", if any.  Some (but not all) mesonets contain data from a 
    number of smaller networks.  In these cases, the "subprovider" for each
    station is the name of the smaller network.  If this field is all blank, then
    there isn't a subprovider associated with the station.  This information can
    also be obtained directly by reading the SUBPVDR variable, which only contains
    the subprovider designation.

    Note that the station location variable isn't available in the AWIPS database 
    for METAR.

22. The PCPUDAY (COOP) variable provides the accumulated precipitation for a 
    24 hour period that can be defined by each individual station.  The UDSTART
    variable can be used to determine the start hour & minute of the "user-defined
    day".  E.g., a UDSTART value of 1330 would mean the 24 hour accumulation
    period starts at 13:30 local time, a value of 200 would represent 02:00.

23. The High Frequency METAR Runway Visual Range (RVRID) is specified
    in degrees.  The location of the RVR runway relative to other
    parallel runways (RVRLOC) is specified as follows:

       Value      Meaning
       -----      -------
       0          no runway parallel to RVR runway
       1          left
       2          center
       3          right

    The RVR distance type (RVRTYPE) variable has the following values:

       Value      Meaning
       -----      -------
       0          between highest and lowest reportable values
       1	  lowest reportable value
       2	  highest reportable value

24.  The High Frequency METAR alert data bitmasks (ALERT1, ALERT2) provide
     an optional means to alert users to an operational value.  This feature
     is optional, and may not be implemented on all stations.  The tables
     below indicate the meaning of bits that may be set in the two words
     (LSB=1, MSB=16).

     ALERT1:

       Bit          Meaning
       ---          -------
       1            Sky Condition, In
       2            Ceiling, Up
       3            Ceiling, Down
       4            Visibility, Increase
       5            Visibility, Decrease
       6            Wind Direction/Preferred Runway Change
       7            Wind Speed, Increase
       8            Reserved
       9            Hail, Begin
       10           Hail, End
       11           Ice Pellets, Begin
       12           Ice Pellets, End
       13           Freezing Rain, Begin
       14           Freezing Rain, End
       15           Freezing Drizzle, Begin
       16           Freezing Drizzle, End

     ALERT2:

       Bit          Meaning
       ---          -------
       1            Thunderstorm, Begin
       2            Thunderstorm, End
       3            Thunderstorm, Increase
       4            Tornado Observed
       5            Funnel Cloud Observed
       6            Water Spout Observed
       7            Reserved
       8            Local Threshold Exceeded
       9            Snow, Begin
       10           Snow, End
       11           Rain, Begin
       12           Rain, End
       13           Non-specific Precip, Begin
       14           Non-specific Precip, End
       15           Fog, Begin
       16           Fog, End

25. The COOP stations have the option to add up to two variables that are specific
    to the individual station.  

26. Commissioned status (COOP):

       Value      Meaning
       -----      -------
       0          commissioned             
       1          not yet commissioned

27. Station quality indicator (COOP):

       Value      Meaning
       -----      -------
       [TBD]

28. All times reported in the MADIS API are in Universal Coordinated Time, with the 
    format of "YYJJJHHMM", where:

    YY  = 2-digit year (good from 1980 - 2179)
    JJJ = Julian date of the year (1-366)
    HH  = Hour (0-23)
    MM  = Minute (0-59)

    If the max/min temperature time is missing, the 9-character field will be set to 
    all blanks, e.g., "         ".

    Users of the MADIS API sfcdump program will get the time output in their chosen
    format, either YYJJJHHMM or YYYYMMDD_HHMM.

29. Some (but not all) mesonets, and the COOP dataset, contain data from a 
    number of smaller networks.  In these cases, the "subprovider" for each
    station is the name of the smaller network.  If this variable is all blank, then
    there isn't a subprovider associated with the station.  

30. The total precipitation variable (COOP, MESONET, High Frequency
    METAR) is an accumulation over a period of unknown duration.
    Stations that report this value will also report the PCP1H and
    PCP24H observations, except for High Frequency METAR, which will
    report PCP1H but not PCP24H.  The High Frequency total
    precipitation values are only available for AWOS stations.  The
    PCPTOTL value is made available for those interested in
    calculating the accumulation over a period of other than 1 or 24
    hours.

31. The COOP door open/closed indicator is used to show when the instrument
    enclosure has been opened for maintenance.

       Value      Meaning
       -----      -------
         0        closed
         1        open

32. The COOP rim heating on/off indicator is used to indicate when rim heating
    is on for the precipitation gauge.

       Value      Meaning
       -----      -------
         0        off
         1        on

33. The stage 3 results from the 5m variables are also assigned to the
    15m variables for UrbaNet.

34. The High Frequency METAR dataset contains the following "remarks" variables:

    Automated remarks status (ARMKST) is a bitmask with set bits indicating 
    the detection of conditions triggering automated remarks (LSB=1, MSB=16):

       Bit          Meaning
       ---          -------
        1           variable visibility
        2           variable wind direction
        3	    variable ceiling
        4	    reserved
        5	    visibility at second location
        6	    ceiling height at second location

    Automated remarks (AUTORMK) encoding
    ------------------------------------

    Variable Visibility  

    The automated remark pertaining to variable visibility is
    expressed as: VSBY aaa(a)Vbbb(b), where aaa(a) and bbb(b) are 3-
    or 4-character, variable-length fields with leading "0" characters
    as necessary to ensure a 3 character minimum, and these represent
    range limits provided in hundredths of statute miles.  For
    example: VSBY 075V250 indicates a variation in visibility between
    0.75 and 2.5 miles.

    (ASOS/AOS Only) A multiple sensor visibility remark is inserted in
    this field in the exact format by which it is prepared for
    insertion as a multiple sensor visibility REMARK in METAR format.
    See FMH-1 for details of the formatting.

    Variable Wind

    The automated remark for variable wind direction is encoded as
    follows when the current average wind speed exceeds 6 knots: 
    WND ccVdd, where cc and dd are 2-character, fixed-length fields 
    with a leading "0" character as necessary, and indicates range
    limits provided in tens of degrees. For example: WND 06V13 denotes
    a variation in the true direction between 60 and 130 degrees.  

    The automated remark for variable wind direction is encoded as
    follows when the current average wind speed is equal to or less
    than 6 knots and five-second wind samples have varied over a range
    of 60 degrees or more over the past two minutes: VRBkkKT, where kk
    is a 2-character, fixed-length field with a leading "0" character,
    and "VRB" and "KT" shall be literals. For example: VRB03KT

    Variable Ceiling (ASOS/AOS Only)

    The automated remark for variable ceiling condition may indicate
    one (for an airport configured with a single cloud sensor) or one
    of two (for an airport configured with multiple cloud sensors)
    cloud conditions.  The format for the single cloud sensor
    configuration is: CIG eeeVfff, and the format for the multiple
    cloud sensor configuration is: 

    CIG eee gggggggg
    CIG eeeVfff
    CHINO gggggggg

    Upper case letters and blanks within individual remarks are
    fixed. Lower case eee,fff are 3-character, fixed-length fields
    with leading "0" character(s) as necessary, and respectively
    represent minimum and maximum ceiling heights, in hundreds of
    feet, above ground level (AGL).

    gggggggg is a 1- to 8-character, variable-length field
    representing one of the eight cardinal directions: "N", "NE", "E",
    "SE", "S", "SW", "W", "NW" and/or additional descriptors such as
    runway designators, etc.

    For example: CIG 008V020 indicates that a variable ceiling base
    height was detected between 800 and 2000 feet.

    Visibility At Second Location (ASOS/AOS Only) 

    The automated remark pertaining to visibility at a second
    location, generated only when this value is less than that
    registered at the primary location, is encoded as: 
    VIS aaaaa gggggggg, where aaaaa is a variable length field of up 
    to 5 characters representing the visibility in fractional format, 
    with a single space character separating the integer and fractional
    parts, and gggggggg is a 1- to 8-character, variable-length field
    representing one of the eight cardinal directions: "N", "NE", "E",
    "SE", "S", "SW", "W", "NW" and/or additional descriptors such as
    runway designators, etc. For example: VIS 1 3/4 RWY22 indicates a
    visibility of one and three quarters statute miles registered at
    the Runway 22 location.

    Ceiling Height At Second Location (ASOS/AOS Only) 

    The automated remark pertaining to ceiling height at a second
    location, generated only when this value is less than that
    registered at the primary location, is encoded as: 
    CIG hhh gggggggg, where hhh is a fixed length field of 3 characters
    representing the measured ceiling height in hundreds of feet, and
    gggggggg is a 1- to 8-character, variable-length field
    representing one of the eight cardinal directions: "N", "NE", "E",
    "SE", "S", "SW", "W", "NW" and/or additional descriptors such as
    runway designators, etc. For example: CIG 003 RWY22 indicates a
    ceiling height of three hundred feet registered at the Runway 22
    location.

    Operator remarks (OPERRMK) are free-formatted text.

35. The High Frequency METAR sensor status variables (DDSS, FFSS, FRZRSS,
    PCPASS, PCPTSS, PSS, RVRSS, SCLBSS, TDSS, TSS, VISSS) indicate the
    operational status of each sensor, as shown in the following table:

       Value      Meaning
       -----      -------
        0         Sensor operating/data available
        1         Reserved
        2         Sensor not installed
        3         Sensor out of service
        4         Reserved
        5         Sensors output in conflict
        6         Invalidated: Auto range check
        7         Invalidated: Auto rate of change
        8         Invalidated: Auto insufficent count
        9         Invalidated: By operator
        10        Data source offsite: Link failure
        11        Reserved
        12        Dewpoint sensor invalidated *
        13        Reserved
        14        Reserved
        15        Reserved
        16        Operator manual data entry

        * Value 12 is only used for the dewpoint sensor (TDSS).

36. The High Frequency METAR operating status (OPSTAT) is a bitmask indicating
    the status of the station as a whole, the meaning of the possible set bits
    (LSB=1, MSB=16) is shown below.

       Bit          Meaning
       ---          -------
        1           Operator on duty
        2           Test Mode
        3           Manual Mode
        4           Part or all data are suspect

37. The High Frequency METAR dataset parameter activation status (PARACT) 
    pertains to obstructions to visibility and precipitation types.  This is
    a bitmask, with set bits indicating that the associated parameters are
    active, i.e., being monitored (e.g. rain or snow), or determined by
    algorithm (e.g., haze, smoke).  (LSB=1, MSB=16)

       Bit          Meaning
       ---          -------
        1           Mist monitoring active
        2           Fog monitoring active
        3           Ground fog monitoring active
        4           Ice fog monitoring active
        5           Haze monitoring active
        6           Smoke monitoring active
        7           Dust, volcanic ash monitoring active
        8           Blowing snow, sand monitoring active
        9           Rain monitoring active
        10          Snow grains monitoring active
        11          Freezing rain monitoring active
        12          Small hail and/or ice pellets monitoring active
        13          Ice pellets monitoring active
        14          Snow monitoring active
        15          Ice crystals monitoring active
        16          Hail monitoring active


* The SAO dataset is only available with the FSL database.