Report of marine surface observation along a ship's track

Code Form:

Section 1 MiMiMjMj YYMMJ -
Section 2 GGgg/ QcLaLaLaLa LoLoLoLoLo
Section 2 4mTmSmcic (6snTwTwTw) (8S0S0S0S0)
Section 2 (9d0d0c0c0) - -
Section 3 D....D - -


  1. TRACKOB is the name of the code for reporting consecutive marine surface observations along a ship's track.
  2. A TRACKOB report containing observations taken on the same date along a ship's track during one day is identified by MiMiMjMj = NNXX and the group YYMMJ, and terminated by the ship's call sign D....D.
  3. A bulletin may contain several TRACKOB reports.
  4. The code is divided into 3 sections:
Section Number Symbolic figure group Contents
1 - Data for reporting identification and date.
2 - Data for reporting time, location, averaging periods, and marine surface parameters.
3 - Ship's call sign


62.1 General
The code name TRACKOB shall not be included in the report.
62.2 Section 1
Section 1 shall be included as the first line of the text in every individual report.
62.3 Section 2
62.3.1 The groups GGgg/ QcLaLaLaLa LoLoLoLoLo shall always be included in each individual observation within a report. The ship's position shall refer to its position at mid-point of beginning and end of observation.
62.3.2 In a TRACKOB report, the group 4mTmsmcic shall be included only for the first observation and omitted for subsequent observations for which the averaging procedures are the same. Whenever any subsequent change occurs in the averaging procedures, the first observation using the subsequent averaging procedures shall include this group.
62.3.3 When data are available, the group 9d0d0c0c0 shall be encoded 90000 if the sea surface current speed is less than 0.05 metres per second (0.1 knot).
62.3.4 Section 2 shall be repeated as often as observations are available for a given date.
62.4 Section 3
The ship's call sign D....D shall be entered at the end of a TRACKOB report and shall terminate an individual report. In the absence of a ship's call sign, the word SHIP shall be used for D....D.
62.5 A bulletin of TRACKOB reports
In a bulletin of several TRACKOB reports from either the same ship or different ships, every individual TRACKOB report shall always include Sections 1,2 and 3, and Section 2 shall conform to Regulation 62.3.4.

Symbolic Letters:

Sea surface current speed, in tenths of a m/s or tenths of a knot, in units indicated by ic. (1) d0d0c0c0 is coded 0000 if the current speed is less than 0.05 m/s (0.1 knot).
True direction in tens of degrees, towards which sea surface current is moving (code table 0877).
Ship's call sign consisting of 3 or more alphanumeric characters.
Time of observation, in hours and minutes (UTC). This is the actual time of launching the bathythermograph.
Indicator for units of sea surface current speed (code table 1833).
Units digit of the year (UTC), i.e. J = 4 for 1994.
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)
Averaging period for surface current direction and speed (code table 2604)
Averaging period for salinity (code table 2604)
Averaging period for sea temperature (code table 2604)
Quadrant of the globe (code table 3333)
Sign of the data and relative humidity indicator (code table 3845)
Salinity, in hundredths of a part per thousand, (practical salinity), at the surface.
Sea surface temperature, in tenths of a degree Celsius, its sign being given by sn.
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.
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