FM 63 X Ext. BATHY

Report of bathythermal observation

Code Form

Section 1 MiMiMjMj YYMMJ GGgg/ QcLaLaLaLa LoLoLoLoLo -
Section 1 (iuddff) (4snTTT) - - - -
Section 2 8888k1 IXIXIXXRXR z0z0T0T0T0 z1z1T1T1T1 . . . . . znznTnTnTn
Section 2 - - 999zz z1z1T1T1T1 . . . . . znznTnTnTn
Section 2 - - (00000) - - -
Section 3 (66666 (1ZdZdZdZd) (k5DcDcVcVc)) - - -
Section 4 D....D or 99999 A1bwnbnbnb - - - -


  1. BATHY is the name of the code for reporting bathythermal observations.
  2. A BATHY report or a bulletin of BATHY reports is identified by MiMiMjMj = JJYY.
  3. The code form is divided into four sections:
Section Number Symbolic figure group Contents
1 - Identification and position data. Wind and air temperature (optional).
2 8888 Type of instrumentation and temperatures at either significant or selected depths.
3 66666 Total water depth and surface current (optional).




Ship's call sign or station identification group A1bwnbnbnb


63.1 The code name BATHY shall not be included in the report.
63.2 Section 1
63.2.1 Each individual BATHY report, even if included in a bulletin of such reports, shall contain as the first group the identification group MiMiMjMj.

For the reporting of the value of the direction and speed of the wind, regulations for FM 13 SHIP shall apply.

Note: The unit of wind speed is indicated by iu (code table 1853)

63.3 Section 2
63.3.1 The group IXIXIXXRXR is mandatory and shall follow immediately after the 8888k1 group.

If temperatures are reported at significant depths, the values shall:

  1. Be sufficient to reproduce basic features of the temperature profile;
  2. Define the top and the bottom of isothermal layers;
  3. In the upper 500 metres, never be more and usually less than 20 in number, even at the cost of loss of detail.
63.3.3 The group 00000 shall be included only when the temperature at the lowest depth of the sounding, which is reported in the last temperature group, is actually the bottom layer temperature.
63.4 Section 3
63.4.1 The inclusion of this section shall be determined by national decision.
63.4.2 Group 1ZdZdZdZd shall be omitted when group 00000 is included in Section 2.
63.5 Section 4

The ship's call sign D .... D, or identifier group 99999 together with the station identification group A1bwnbnbnb if not already included in the report, shall be added by the coastal radio station receiving the report, or the national collecting centre when preparing the report for inclusion in bulletins, as appropriate and required.


  1. See Regulation 12.1.7.
  2. See Regulation 18.2.3, Notes (1), (2) and (3).

Symbolic Letters:

WMO regional association area in which buoy, drilling rig or oil- or gas-production platform has been deployed(1 - Region I; 2 - Region II, etc.) (code table 0161).
Subarea belonging to the area indicated by A1 (code table 0161).
Surface current direction, in tens of degrees.
Ship's call sign consisting of 3 or more alphanumeric characters.
True direction, in tens of degrees, from which wind is blowing (or will blow) (code table 0877; stations within 1 degree of the North pole use code table 0878)
Wind speed in units indicated by iu
Time of observation, in hours and minutes (UTC). This is the actual time of launching the bathythermograph.
Instrument type of XBT, with fall rate equation coefficients (code table 1770).
Indicator of units of wind speed and type of instrumentation (code table 1853)
Units digit of the year (UTC), i.e. J = 4 for 1994.
Indicator for digitization (code table 2262).
Indicator for the method of current measurement (code table 2266).
Latitude in degrees and minutes
Longitude in degrees and minutes
Month of the year (UTC), i.e. 01= January; 02 = February, etc.
Identification letters of the report (code table 2582)
Identification letters of the part of the report or the version of the code form (code table 2582)
Type and serial number of buoy.
Quadrant of the globe (code table 3333)
Sign of the data and relative humidity indicator (code table 3845)
Air temperature, in tenths of a degree Celsius, its sign being given by sn
T0T0T0 T1T1T1 ... TnTnTn
Temperatures, in tenths of a degree Celsius, at specified depths starting with the sea surface. For negative temperatures, 500 shall be added to the absolute value of the temperature in tenths of a degree Celsius.
Surface current speed, in tenths of a knot.
Recorder type (code table 4770).
Day of the month (UTC), with 01 indicating the first day, 02 the second day, etc., on which the actual time of the observation falls.
Total water depth, in meters.
Depth, in hundreds of meters, starting with the surface.
z0z0 z1z1 … znzn
Significant depths, in meters, starting with the surface
/// …
Missing data. The number of solidi depends on the number of symbolic letters for which no data can be reported.
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