Bathythermal and Salinity Observations

  1. BTSC Report
    1. BTID Element
    2. BTCODE Element
    3. BTLEVELS Element
      1. BTAIR Element
      2. BTLEVEL Element
  2. Example
  3. References (bibliography)


BTSC Report

This element defines an observation report on temperature, salinity and currents at one particular location on the ocean surface, or in subsurface layers. These data are distributed in FM 63 X BATHY, FM 64 IX and X TESAC and FM 62 TRACKOB reports. The main component of the BTSC element is a sequence of BTLEVELs that describe physical characteristics of sea water (temperature, salinity and flow) at particular depth levels.

Chapter 4 of a NCAR Technical Note 404 covers in great detail the scope of surface and subsurface oceanographic observations, especially in situ observations, which are annotated in this document. "In order to understand oceanic circulation, it is necessary to know the internal distribution of water mass (e.g., density) within the ocean. The distribution of ocean water density is defined by the water temperature, salinity, and pressure or depth. Measurements of these water properties are generally made with vertical profiling instruments lowered from research ships."

Raw BATHY, TESAC, and TRACKOB observation reports are highly encoded, which obscures the meaning of data and impedes their usage. Without consulting special coding tables, the information in these reports is inaccessible. The OMF is to redress this situation by annotating raw reports with decoded information, in conventional and self-evident units.

The OMF markup described in this document only annotates the raw text of oceanographic profile reports, without altering them or omitting a single letter. An annotated BTSC document arranges the information in a logical sequence, which is most suitable for further analysis. Yet it is always possible to reconstruct the original report in its entirety. In case of a coding or transmission error, the corresponding data are marked with a specific tag. It is up to an application then to try to correct the error and salvage whatever data possible.



 Time Stamp of the observation
 Location of a point where the observation was taken
 Station identification

For a buoy or other observation platform, this id is a combination of a WMO region number, subarea number (per WMO Code Table 0161), and the buoy type and serial number. This information is reported in Section 4 of a BTSC report.

 Ship's call sign, if any
 Type of the original report this BTSC element annotates
  • "JJYY" - FM 63 X Ext. BATHY report
  • "JJVV" - FM 63 X Ext. 98 BATHY report
  • "KKXX" - FM 64 IX TESAC report
  • "KKYY" - FM 64 X TESAC report
  • "NNXX" - FM 62 TRACKOB report
  The three reports above carry basically the same type of data, which are annotated in a BTSC element. This Title attribute tells which particular report the information came from [See WMO Code table 2582]
 Total water depth at the point of observation a positive number, in meters; may be omitted
LimitTo, LimitRecd
 Access Restrictions

	%TStamp; %LatLon; %BId; %SName; %AccessLimit;


BTID Element

The BTID element annotates identification and position data, which constitute Section 1 of FM 62 - 64. Attributes of this element provide information on instruments and measurement procedures that were used to perform the observation.



 Indicator for digitization "7" or "8" or omitted
  k1 code (code table 2262)
Required for BATHY and TESAC reports
 Code of a bathythermograph used an NMTOKEN
A 5-digit code of a type and make of a bathythermograph
  the first three digits IXIXIX encode an XBT type and fall rate coefficients as per code table 1770. The other two digits XRXR are the bathythermograph make and model. See references below for more details. The Rec attribute is required for BATHY reports and for FM 64 X TESAC reports.
 Indicator for wind speed units and instrument certification "0", "1", "2", "3", or omitted
  iu code (code table 1853)
even values mean the wind speed is in meters/sec; odd values stand for knots. Values 0 and 1 indicate land stations or ships with certified instruments.
This attribute is always present if the wind speed and direction are reported.
 Indicator for the method of sea surface current measurement "2", "3", "4", or omitted
  k5 code (code table 2266)
This attribute is always present if the sea current information is reported
 Indicators for the method of subsurface current measurement an NMTOKEN: three digits
  k6 k4 k3 codes: see the references below
These indicators are provided only for a TESAC report as it is the only one that may contain data on subsurface ocean currents
 Averaging period for sea temperature "0", "1", "2", "3", or omitted (if no sea temperature data are reported)
  mT code: see the references below
 Averaging period for salinity "0", "1", "2", "3", or omitted (if no salinity data are reported)
  mS code: see the references below
 Averaging period for surface current direction and speed "0", "1", "2", "3", or omitted (if no current data are reported)
  mc code: see the references below
 Method of salinity/depth measurement "1", "2", "3", or omitted (if salinity is not measured)
  k2 code (code table 2263)

	DZ (7|8) #IMPLIED
	WS (0|1|2|3) #IMPLIED
	Curr-s (2|3|4) #IMPLIED
	AV-T (0|1|2|3) #IMPLIED
	AV-Sal (0|1|2|3) #IMPLIED
	AV-Curr (0|1|2|3) #IMPLIED
	Sal (1|2|3) #IMPLIED

BTCODE Element

The BTCODE element marks up those tokens of the original message that are unparsed or cannot be parsed. Occasionally some of report's data cannot be parsed because they were wrongly encoded or garbled during transmission.

Regardless of the reason, the unparsed parts of a report are thus clearly identified so an application may attempt to extract or salvage whatever information possible. The present markup format does not correct or modify these unparsed pieces, and does not annotate them any further. The unparsed tokens identified by a BTCODE element always occur at the very end of a report. This implies that there may be at most one BTCODE element within a single BTSC report.



This element contains a sequence of BTLEVEL elements for each particular (sub)surface level described in a whole BTSC report. The BTLEVELs occur in the order of increasing depth, starting with D='0' for the sea surface layer. An optional BTAIR element may be given to tell the temperature and the air flow (wind vector) of the air above the sea surface.



BTAIR Element

The optional BTAIR element describes the air above the sea surface. The body of the element is one or two encoded tokens from Section 1 of FM 62 - 64 reports. Element's attributes spell out this information in "plain text". Note, the wind direction is the true direction the wind is blowing from. This is the opposite of a sea current specification, which tells the direction the current is moving towards.



 the air temperature (above the sea surface) a positive, zero or negative number, in degrees Celsius; may be omitted
 wind vector a string of a form "nnn, mm" or omitted
  Here nnn is a true direction from which the wind is blowing, in degrees, or VAR if " the wind is variable, or all directions or unknown or waves confused, direction indeterminate." This is an integer number within [0,360), with 0 meaning the wind is blowing from the true North, 270 stands for the wind blowing from the West. Normally this number has a precision of 10 degrees.
mm is the wind speed in meters per second.




The BTLEVEL element is the most interesting one as it conveys detailed information about one (sub)surface level -- both in a raw and decoded formats. The body of the element is encoded information about a depth level exactly as it appeared in a raw report. A required D attribute tells the corresponding depth value. The other attributes of a BTLEVEL element present the element's encoded data in a fully-decoded, self-contained format.



 water depth a non-negative number, in meters.
  The value of 0 corresponds to the surface of the ocean
 the sea water temperature at a given depth or at the surface a positive, zero or negative number, in degrees Celsius; may be omitted
 (practical) Salinity a positive number, in parts per thousand; may be omitted
 Current vector at a particular depth or at the surface a string of a form "nnn, mm" or omitted.
  Here nnn is a true direction towards which the sea current is moving, in degrees, or VAR if "the wind is variable, or all directions or unknown or waves confused, direction indeterminate." This is an integer number within [0,360), with 0 meaning the current flows towards the true North, 270 stands for the current moving to the West. Normally this number has a precision of 10 degrees.
mm is the speed of current in meters per second.



OMF Example

A sample of original oceanographic reports:
JJYY 04118 1800/ 13754 13432^M^M
88887 81099 00200 50197 99901 00158^M^M
99999 21002=^M^M

JJYY 18108 00351 13105 13008 88888 00205 00275 61267 67258 00000 ^M^M

JJYY 26108 1310/ 70626 13838 22408 40230 88888 05205 02269 32267^M^M
45256 64249 99238 99901 21223 28218 35215 40203 43199 48187 50184^M^M
52177 56174 60163 63154 69147 80136 99902 03121 31117 73109 99904^M^M
58091 99906 91066 99907 60061 66666 14710 30910 D5NZ=^M^M

JJVV 01043 0420/ 316825 108651 88888 05203 00287 42285 58268 80241
99901 16228 ELES7=

NNXX 04118 2300/ 50053 16151 41199 60257 83526 WTEU=

KKXX 24108 1547/ 70213 02536 88870 20003 32822 20008 32821 20014  ^M^M
32821 20019 32821 20025 32821 20030 32820 20035 32820 20041 32814 ^M^M
99999 13859=

KKYY 31033 1359/ 707302 041055 88870 84560 20004 32661 20010 32661
20015 32659 20020 32658 20025 32657 99999 39007=

would be represented as
<Reports TStamp="910835380">

<BTSC Title='JJYY' TStamp='910202400' LatLon='37.900, 134.533' BId='21002'
SName=', '>
<BTID DZ='7' Rec='81099'>04118 1800/ 13754 13432</BTID>
<BTLEVEL D='0' TW='20.0'>00200</BTLEVEL>
<BTLEVEL D='50' TW='19.7'>50197</BTLEVEL>
<BTLEVEL D='100' TW='15.8'>99901 00158</BTLEVEL>

<BTSC Title='JJYY' TStamp='908670900' LatLon='31.083, 130.133' BId='2473109'
SName='VKNG, ' Depth='67'>
<BTID DZ='8' Rec='00205'>18108 00351 13105 13008</BTID>
<BTLEVEL D='0' TW='27.5'>00275</BTLEVEL>
<BTLEVEL D='61' TW='26.7'>61267</BTLEVEL>
<BTLEVEL D='67' TW='25.8'>67258 00000</BTLEVEL>

<BTSC Title='JJYY' TStamp='909407400' LatLon='6.433, -138.633' BId='1613880'
SName='D5NZ, ' Depth='4710'>
<BTID DZ='8' Rec='05205' WS='2' Curr-s='3'>26108 1310/ 70626 13838</BTID>
<BTAIR T='23.0' Wind='240, 8'>22408 40230</BTAIR>
<BTLEVEL D='0' Curr='90, 0.5'>30910</BTLEVEL>
<BTLEVEL D='2' TW='26.9'>02269</BTLEVEL>
<BTLEVEL D='32' TW='26.7'>32267</BTLEVEL>
<BTLEVEL D='45' TW='25.6'>45256</BTLEVEL>
<BTLEVEL D='64' TW='24.9'>64249</BTLEVEL>
<BTLEVEL D='99' TW='23.8'>99238</BTLEVEL>
<BTLEVEL D='121' TW='22.3'>99901 21223</BTLEVEL>
<BTLEVEL D='128' TW='21.8'>28218</BTLEVEL>
<BTLEVEL D='135' TW='21.5'>35215</BTLEVEL>
<BTLEVEL D='140' TW='20.3'>40203</BTLEVEL>
<BTLEVEL D='143' TW='19.9'>43199</BTLEVEL>
<BTLEVEL D='148' TW='18.7'>48187</BTLEVEL>
<BTLEVEL D='150' TW='18.4'>50184</BTLEVEL>
<BTLEVEL D='152' TW='17.7'>52177</BTLEVEL>
<BTLEVEL D='156' TW='17.4'>56174</BTLEVEL>
<BTLEVEL D='160' TW='16.3'>60163</BTLEVEL>
<BTLEVEL D='163' TW='15.4'>63154</BTLEVEL>
<BTLEVEL D='169' TW='14.7'>69147</BTLEVEL>
<BTLEVEL D='180' TW='13.6'>80136</BTLEVEL>
<BTLEVEL D='203' TW='12.1'>99902 03121</BTLEVEL>
<BTLEVEL D='231' TW='11.7'>31117</BTLEVEL>
<BTLEVEL D='273' TW='10.9'>73109</BTLEVEL>
<BTLEVEL D='458' TW='9.1'>99904 58091</BTLEVEL>
<BTLEVEL D='691' TW='6.6'>99906 91066</BTLEVEL>
<BTLEVEL D='760' TW='6.1'>99907 60061</BTLEVEL>

<BTSC Title='JJVV' TStamp='1049170800' LatLon='-16.825, 108.651'
         BId='2473110' SName='ELES7, '>
<BTID DZ='8' Rec='05203'>01043 0420/ 316825 108651</BTID>
<BTLEVEL D='0' TW='28.7'>00287</BTLEVEL>
<BTLEVEL D='42' TW='28.5'>42285</BTLEVEL>
<BTLEVEL D='58' TW='26.8'>58268</BTLEVEL>
<BTLEVEL D='80' TW='24.1'>80241</BTLEVEL>
<BTLEVEL D='116' TW='22.8'>99901 16228</BTLEVEL>

<BTSC Title='NNXX' TStamp='910220400' LatLon='-0.883, -161.85' BId='2531119'
SName='WTEU, '>
<BTID AV-T='1' AV-Sal='1'>04118 2300/ 50053 16151</BTID>
<BTLEVEL D='0' TW='25.7' S='35.26'>60257 83526</BTLEVEL>

<BTSC Title='KKXX' TStamp='909244020' LatLon='2.217, -25.600' BId='13859'
SName=', '>
<BTID DZ='7'>24108 1547/ 70213 02536</BTID>
<BTLEVEL D='3' TW='28.22'>20003 32822</BTLEVEL>
<BTLEVEL D='8' TW='28.21'>20008 32821</BTLEVEL>
<BTLEVEL D='14' TW='28.21'>20014 32821</BTLEVEL>
<BTLEVEL D='19' TW='28.21'>20019 32821</BTLEVEL>
<BTLEVEL D='25' TW='28.21'>20025 32821</BTLEVEL>
<BTLEVEL D='30' TW='28.20'>20030 32820</BTLEVEL>
<BTLEVEL D='35' TW='28.20'>20035 32820</BTLEVEL>
<BTLEVEL D='41' TW='28.14'>20041 32814</BTLEVEL>

<BTSC Title='KKYY' TStamp='1049119140' LatLon='7.302, -41.055' BId='39007'
SName=', '>
<BTID DZ='7' Rec='84560'>31033 1359/ 707302 041055</BTID>
<BTLEVEL D='4' TW='26.61'>20004 32661</BTLEVEL>
<BTLEVEL D='10' TW='26.61'>20010 32661</BTLEVEL>
<BTLEVEL D='15' TW='26.59'>20015 32659</BTLEVEL>
<BTLEVEL D='20' TW='26.58'>20020 32658</BTLEVEL>
<BTLEVEL D='25' TW='26.57'>20025 32657</BTLEVEL>




JCOMM - Joint Commission on Oceanography and Marine Meteorology. Code forms.

FM 63 XI Ext. BATHY - Report of bathythermal observation CODE FORM

Guide To Operational Procedures For The Collection And Exchange Of JCOMM Oceanographic Data. Third Revised Edition

An Introduction to Atmospheric and Oceanographic Datasets - NCAR Technical Note 404
A "data-primer" for students and those in other fields of research who are interested in the analysis of atmospheric and oceanographic sciences

The OMF Data Definition Document in XML format

Sample OMF BTSC document

Query for the latest Bathythermal, Salinity and ocean current observation reports
The reports are presented in the OMF format described in this document.


$Id: OMF-BATHY.html,v 1.7 2007/02/21 01:11:40 oleg Exp oleg $