The header SSVX identifies bulletins of observations coded in FM 18-X.
Note: This code form replaced the former FM 18-IX Ext DRIFTER code.

Observations from buoys similar to observations from ships are encoded in the
SHIP code, FM 12 or FM 13, and are included in bulletins headed SMV/, SIV/ etc.

For a full decode please refer to the WMO Manual on Codes, Volume I.1 Part A: Alphanumeric codes
WMO Publication No 306, available from: The WMO Secretariat
at PO Box 2300, CH-1211 Geneva 2, Switzerland, price Sw Fr 130.- (February 1998)

The following Sections are only included if there are data available
 
SECTION 0  Identification, time and position data 
           MiMiMjMj A1bwnbnbnb YYMMJ GGggiw QcLaLaLaLaLa LoLoLoLoLoLo (6QiQt//)

SECTION 1  Meteorological and other non-marine data
           (111QdQx 0ddff 1snTTT 2snTdTdTd OR 29UUU 3P0P0P0P0 4PPPP 5appp

SECTION 2  Surface marine data
           (222QdQx 0snTwTwTw 1PwaPwaHwaHwa ..... .....

SECTION 3  Temperatures, salinity and current (when available) 
           at selected depths 
           333Qd1Qd2 .....  .....

SECTION 4  Information on engineering and technical parameters 
           including quality control data) 
           444 (1QpQ2QTwQ4) ..... .....

INTERPRETATION

SECTION 0 (Identification, time and position data)

MiMiMjMj                  Always coded as ZZYY 

A1bwnbnbnb                The buoy number or identifier
             A1bw        The WMO Region and sub-region in which the 
                          buoy was deployed, eg 62 includes the seas around
                          the UK and to the west and south-west of the British
                          Isles.
             nbnbnb       Type and serial number of the buoy (500 is added to 
                          the serial number when the buoy is a drifting buoy)

YYMMJ        YY          Date
             MM          Month
             J           Last digit of the year

GGggiw       GGgg        Time of the observation
             iw          Indicator for source and units of wind speed
                         0 or 1: Wind speed metres/sec; 3 or 4: Wind speed knots

QcLaLaLaLaLa   Qc          Quadrant of the globe
                          N hemisphere: 7 is degrees West, 1 is degrees East
                          S hemisphere: 5 is degrees West, 3 is degrees East
             LaLaLaLaLa   Latitude (eg 54126 decoded as 54.126 degrees, 54.12/ 
                          decoded as 54.12 degrees and 541// as 54.1 degrees)

LoLoLoLoLoLo              Longitude (eg 132463 decoded as 132.463 degrees, 05621/
                          decoded as 56.21 degrees, and 1458// as 145.8 degrees

(6QiQt//)                Quality control indicators (see WMO Manual on Codes)

SECTION 1 (Meteorological and other non-marine data)

111QdQx               Quality control indicators for the section

0ddff       0         Indicator
            dd        Wind direction in tens of degrees
            ff        Wind speed in knots or m/s

1snTTT      1         Indicator
            sn        Sign of temperature - 0: positive or zero, 1: negative
            TTT       Dry-bulb temperature in tenths of a degree Celsius

2snTdTdTd    2         Indicator
            sn        Sign of temperature
            TdTdTd     Dew-point temperature in tenths of a degree Celsius

  OR

29UUU       2         Indicator
            9         Relative humidity follows
            UUU       Relative humidity expressed as a percentage:
                        first figure zero except when UUU is 100 percent


3P0P0P0P0    3         Indicator
            P0P0P0P0   Pressure at station level, in tenths 
                        of a millibar, omitting the thousands digit

4PPPP       4         Indicator
            PPPP      Mean sea level pressure, in tenths of a millibar, 
                        omitting the thousands digit

5appp       5         Indicator
            a         Characteristic of pressure change 
            ppp       Pressure change over last three hours in tenths of a millibar

Return to Codes Index. 

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Created by MWS: 15th February 1998

Dave Wheeler weatherman@zetnet.co.uk

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