
Bathythermograph (BT) Data

    The following group of four related files contains temperature profile
data (temperature versus depth) from the mechanical bathythermograph (MBT)
and its successor instrument, the expendable bathythermograph (XBT).  
Although the NODC still receives some MBT data (in digital form) from
foreign sources, most new data are from XBTs.  XBT data are received in
delayed mode as analog strip charts (that must be digitized), as digital
data already derived from analog strip charts, and, increasingly, as digital
data recorded directly on cassette tapes by newer XBT systems.  NODC also 
receives BT data in near-real-time as telecommunicated (radio message)
observations collected in support of the Integrated Global Ocean Services
System (IGOSS).  Because they vary in quality, the way in which they are
reported to the NODC, and the depths at which they are recorded, the data
are maintained in separate files.  The data are all recorded in the same
format, however, and may be merged if desired.


File: MECHANICAL BATHYTHERMOGRAPH (MBT) DATA                      
Geographic Coverage:  Worldwide Oceans                            
Time Period:  1941 to 1988

Description:                                                      
     This file contains temperature-depth profile data
obtained using the mechanical bathythermograph (MBT) instrument. 
The maximum depth of MBT observations is approximately 285 m. 
Therefore, MBT data are useful only in studying the thermal
structure of the upper layers of the ocean.  Cruise information,
date, position, and time are reported for each observation. The
data record comprises pairs of temperature-depth values.
Temperature data in this file are recorded at uniform 5 m depth
intervals.                                                
(Note:  The mechanical bathythermograph instrument is now obsolete,
having been superseded by the faster, easier-to-operate expendable
bathythermograph.)        


File: EXPENDABLE BATHYTHERMOGRAPH (XBT) DATA                      
Geographic Coverage:  Worldwide Oceans                            
Time Period:  1965 to Present   

Description:                                                      
     This file contains temperature-depth profile data
obtained using expendable bathythermograph (XBT) instrument. 
Standard XBTs can obtain profiles at depths of about 450 or 760 m.
With special instruments, measurements can be obtained to 1830 m.
Cruise information, position, date, and time are reported for each 
observation.  The data record comprises pairs of temperature-depth
values. Unlike the MBT data file, in which temperature values are
recorded at uniform 5m intervals, the XBT Data File contains
temperature values at non-uniform depths. These depths are at a
minimum number of points ("inflection points") required to record
the temperature curve to an acceptable degree of accuracy. On
output, however, the user may request temperature values either at
inflection points or interpolated to uniform depth increments.    
      

File:  SELECTED DEPTH BATHYTHERMOGRAPH DATA (SBT)                 
Geographic Coverage: Global                                       
Time Period: 1947 - 1992    

Description:                                                      
     This file contains temperature-depth data obtained from
mechanical (MBT) and expendable (XBT) bathythermograph instruments.
Data in this file were sent to NODC at depths selected by the
originator - usually at standard horizons or some fixed interval. 
The MBT file holds data reported at a 5-meter depth interval, and
depths in the XBT file are chosen at significant inflection points
of the temperature-depth profile. SBT data can be selected from
specific geographic regions or from specified cruises.            


File:  RADIO MESSAGE BATHYTHERMOGRAPH DATA (IBT)
Geographic Coverage:  Worldwide oceans

Description:
     This file contains telecommunicated bathythermograph 
(principally XBT) data transmitted by ships at sea over the Global
Telecommunications System in the Integrated Global Ocean Services 
System (IGOSS) BATHY format.  These data are accumulated and transmitted
to NODC from two U.S. operational centers: the NOAA National Meteorological
Center (NMC) and the U.S. Navy Fleet Numerical Oceanography Center (FNOC).
Like XBT data, IBT data temperature values are recorded at inflection 
point depths.  The BATHY radio message allows for a limited number of 
depth-temperature pairs to be reported, however.  Therefore, compared
to delayed-mode XBT data, IBT data present a coarser representation
of ocean temperature profiles.                       

File Structure:
     One variable-length record (maximum 2,540 characters).


File Format:
(Universal for all four BT data types)


                       Bathythermograph Data (BT)


PARAMETER               DESCRIPTION                                     SC   FL

FILE ID                 TWO-CHARACTER CODE -                             1    2
                        ('X '=XBT AT INFLECTION POINT DEPTHS;
                         'M '=MBT AT 5-METER DEPTHS;
                         'XS'=XBT AT ORIGINATOR DEPTHS;
                         'MS'=MBT AT ORIGINATOR DEPTHS)
AREA                    ONE-DIGIT CODE - WMO QUADRANT (= 1, 3, 5, OR 7)  3    1
LATITUDE                DDMMX (DEGREES, MINUTES TO TENTHS)               4    5
LATITUDE HEMISPHERE     ONE-CHARACTER CODE - 'N' OR 'S'                  9    1
LATITUDE PRECISION      ONE-DIGIT CODE - USE NODC CODE 0606             10    1
LONGITUDE               DDDMMX (DEGREES, MINUTES TO TENTHS)             11    6
LONGITUDE HEMISPHERE    ONE-CHARACTER CODE - 'E' OR 'W'                 17    1
LONGTITUDE PRECISION    ONE-DIGIT CODE - USE NODC CODE 0606             18    1
DATE (GMT)              YYMMDD - YEAR, MONTH, DAY                       19    6
TIME (GMT)              XXXX (HOURS AND MINUTES)                        25    4
TIME PRECISION          ONE-DIGIT CODE - USE NODC CODE 0607             29    1
BLANK                   ONE BLANK                                       30    1
SUBMITTING COUNTRY      TWO-CHARACTER NODC COUNTRY CODE                 31    2
BLANK                   ONE BLANK                                       33    1
SUBMITTING INSTITUTION  TWO-CHARACTER NODC INSTITUTION CODE             34    2
CRUISE                  XXXXX - NODC CRUISE NUMBER                      36    5
CONSEC                  XXXX - NODC CONSECUTIVE STATION NUMBER          41    4
DATA ORIGIN
  COUNTRY OF PLATFORM   TWO-CHARACTER COUNTRY CODE                      45    2
  INSTITUTION           TWO-CHARACTER INSTITUTION CODE                  47    2
  PLATFORM              TWO-CHARACTER PLATFORM CODE                     49    2
OSV FLAG                ONE-CHARACTER CODE - INDICATES OCEAN STATION    51    1
                         VESSEL (OCEAN WEATHER STATION)-USE NODC CODE 0610
DNP FLAG                ONE-CHARACTER CODE - INDICATES DECLARED         52    1
                         NATIONAL PROGRAM STATUS-USE NODC CODE 0609
BLANK                   TWO BLANKS                                      53    2
CRUISE                  XXXXXXXX - ORIGINATOR'S CRUISE NUMBER           55    8
CONSEC                  XXXX - ORIGINATOR'S CONSECUTIVE STATION NUMBER  63    4
XBT CALIBRATION DEPTH   XXX - DEPTH AT CALIBRATION TICK; UNITS          67    3
                         (METERS, FEET) DEPENDING ON PROBE TYPE
XBT CALIBRATION         XXX - TEMPERATURE AT CALIBRATION TICK;          70    3
 TEMPERATURE             (DEG C TO TENTHS OR DEG F TO TENTHS, DEPENDING
                         ON PROBE TYPE)
INSTRUMENT TYPE         ONE-DIGIT CODE - (1 = XBT, 2 = HXBT, 3 = SXBT,  73    1
                         4 = AXBT, BLANK = MBT)
MBT GRID OR XBT PROBE   ONE-CHARACTER CODE - USE NODC CODE 0616 OR      74    1
 TYPE                    CODE 0611
XBT BOTTOM FLAG         ONE-CHARACTER CODE - INDICATES WHETHER XBT      75    1
                         PROBE HIT BOTTOM (B = YES, BLANK = NO - NODC
                         CODE 0617)
XBT DIGITIZATION        TWO-DIGIT CODE - USE NODC CODE 0612             76    2
 METHOD
XBT DIGITIZATION        TWO-DIGIT CODE - USE NODC CODE 0613             78    2
 INTERVAL
XBT DATA TREATMENT AND  TWO-DIGIT CODE - USE NODC CODE 0614             80    2
 STORAGE
BOTTOM DEPTH            XXXX (WHOLE METERS)                             82    4
MBT CORRECTION DEPTH    XXX (WHOLE METERS; NEGATIVE VALUE PRECEDED      86    3
                         BY MINUS SIGN)
MBT TEMPERATURE         XXX (DEG C TO TENTHS; NEGATIVE VALUE PRECEDED   89    3
 CORRECTION              SIGN)
MBT REFERENCE           ONE-DIGIT CODE - USE NODC CODE 0615             92    1
 TEMPERATURE TYPE
MBT REFERENCE           XXX (DEG C TO TENTHS)                           93    3
 TEMPERATURE
COUNT                   XXXX - NUMBER OF DEPTH -TEMPERATURE PAIRS       96    4
                         (MAXIMUM = 305)
BLANK                   ONE BLANK                                      100    1
DEPTH*                  XXXX (WHOLE METERS)                            101    4
TEMPERATURE*            XXXX (DEG C TO HUNDREDTHS)                     105    4
*DEPTH-TEMPERATURE PAIRS (8 CHARACTERS) REPEATED AS MANY TIMES AS INDICATED BY
'COUNT' FIELD UP TO MAXIMUM OF 305 PAIRS (2440 CHARACTERS); MAXIMUM RECORD
LENGTH, THEREFORE EQUALS 2440 + 100 (HEADER INFORMATION) = 2540 CHARACTERS.

NODC Code Tables Used with this Format -
   CODE NUMBER                     CODE NAME

   0606                            POSITION PRECISION
   0607                            TIME PRECISION
   0609                            DECLARED NATIONAL PROGRAM
   0610                            OCEAN WEATHER STATION
   0611                            XBT PROBE TYPE
   0612                            DIGITIZATION METHOD
   0613                            DATA INTERVAL (XBT)
   0614                            DATA TREATMENT AND STORAGE
   0615                            BT REFERENCE TEMPERATURE
   0616                            UBT FILE ID
   0617                            BOTTOM HIT
    --                             NODC COUNTRY CODE
    --                             NODC PLATFORM (SHIP) CODE
    --                             NODC INSTITUTION CODE

 0606   POSITION PRECISION  
 ----   --------------------
      1 -- POSITION ACCURATE TO THE NEAREST MINUTE OF LATITUDE OR
           LONGITUDE 
      2 -- POSITION ACCURATE TO THE NEAREST TENTH OF DEGREE OF
           LATITUDE OR LONGITUDE. IF THE
           PRECISION CODE IS "2", THEN THE LATITUDE MINUTES OR
           LONGITUDE MINUTES   
           FIELD CONTAINS A TENTH OF DEGREE MEASURE
           POSITION ACCURATE TO THE NEAREST WHOLE DEGREE OF
           LATITUDE OR WHOLE DEGREE OF LONGITUDE  
      4 -- POSITION ACCURATE TO THE NEAREST TENTH OF MINUTE OF
           LATITUDE OR LONGITUDE

 0607   TIME PRECISION  
 ----   --------------------
      1 -- TIME ACCURATE TO THE NEAREST MINUTE  
      2 -- MINUTES FIELD CONTAINS A TENTH OF HOUR MEASURE   
           TIME ACCURATE TO THE NEAREST TENTH OF AN HOUR. IF THE
           PRECISION CODE IS "2", THEN THE   
           TIME ACCURATE TO THE NEAREST HOUR   

 0610   OCEAN WEATHER STATION
 ----   --------------------
      A -- ALPHA    - 62 N 33 W 
      B -- BRAVO    - 56-30 N 51 W  
      C -- CHARLIE  - 52-45 N 35-30 W   
      D -- DELTA    - 44 N 41 W 
      E -- ECHO     - 35 N 48 W 
      H -- HOTEL    - 38 N 71 W 
      I -- INDIA    - 59 N 19 W 
      J -- JULIET   - 52-30 N 20 W  
      K -- KILO     - 45 N 16 W 
      L -- LIMA     - 57 N 20 W 
      M -- MIKE     - 66 N 2 E  
      N -- NOVEMBER - 30 N 140 W
      P -- PAPA     - 50 N 145 W
      R -- ROMEO    - 47 N 17 W 
      T -- "T"      - 29 N 135 W
      V -- VICTOR   - 34 N 164 E
      X -- "V"      - 39 N 153 E

 0611   XBT PROBE TYPE  
 ----   --------------------
      1 -- 2500 FEET (XBT) SIPP T7  
      2 -- 760 METERS (XBT)SIPP T7  
      3 -- 1500 FEET       SIPP T4 OR T6
      4 -- 460 METERS      SIPP T4 OR T6
      5 -- 1830 METERS     SIPP T5  
      6 -- 200METERS       SIPP. T10
      7 -- 660 FEET        SIPP. T10
      9 -- 6000 FEET       SIPP. T5 
      A -- FAST XBT 1500 FEET (FINE STRUCTURE T11 XBT)  
      B -- FAST XBT 460 METERS (FINE STRUCTURE T11 XBT) 
      C -- 660 FEET WITH MK5 RECORDER   
      D -- ANY PROBE WITH MK8 LINEAR RECORDER   

 0612   DIGITIZATION METHOD 
 ----   --------------------
     01 -- MANUAL   
     02 -- A-D CONVERSION FROM ORIGINAL 
     03 -- A-D CONVERSION FROM COPIES   
     04 -- OPTICAL SCANNING 
     05 -- DIRECT DIGITAL OUTPUT UNKNOWN
     06 -- DIRECT DIGITAL OUTPUT BATHY  
     07 -- DIRECT DIGITAL OUTPUT SUTRON 
     08 -- DIRECT DIGITAL OUTPUT FROM SIPPICAN MARK 9   

 0613   DATA INTERVAL (XBT) 
 ----   --------------------
     01 -- FIXED INTERVAL LE 0.1 METER AND LE 0.1 DEG C 
     02 -- FIXED INTERVAL GT 1 METER BUT LE 3 METERS AND LE 0. 1
           DEG C  
     03 -- FIXED INTERVAL GT 3 METERS BUT LE 6 METERS AND LE 0 .1
           DEG C 
     04 -- FIXED INTERVAL GT 6 METERS AND LE 0.1 DEG C  
     11 -- FIXED INTERVAL LE 1 METER AND LE 0.2 DEG C   
     12 -- FIXED INTERVAL GT 1 METER BUT LE 3 METERS AND LE 0. 2
           DEG C  
     31 -- VARIABLE INTERVAL - MANUALLY DETERMINED  
     32 -- VARIABLE INTERVAL - STATISTICALLY DETERMINED 
     33 -- VARIABLE INTERVAL - PHYSICALLY DETERMINED
     FI -- XED INTERVAL GT 3 METERS BUT LT 6 METERS AND LE 0.2 
           DEG C   
    
 0614   DATA TREATMENT AND STORAGE
 ----   --------------------
     01 -- SINGLE DIGITIZATION; STORED AS DIGITIZED 
     02 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.05 DEG
           C 
     03 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.1 DEG
           C  
     04 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.2 DEG
           C  
     05 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.3 DEG
           C  
     06 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.7 DEG
           C  
     21 -- DUAL DIGITIZATION AND AVERAGING; STORED AS DIGITIZE 
     22 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.05 DEG C 
     23 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.1 DEG C  
     24 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.2 DEG C  
     25 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.3 DEG C  
     26 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.5 DEG C  

 0615   BT REFERENCE TEMPERATURE
 ----   --------------------
      1 -- BUCKET   
      2 -- INJECTION, OR UNVERIFIED BUCKET NOTATION, OR UNKNOWN 
      3 -- NANSEN CAST (REVERSING THERMOMETER)  
      4 -- THERMOGRAPH  
      5 -- SPECIAL CALIBRATION THERMOMETER OR EQUIPMENT 
      6 -- BT   
      7 -- STD  
      9 -- BLANK

 0616   UBT FILE ID 
 ----   --------------------
     M  -- MBT  
     MS -- MBT STANDARD LEVEL   
     X  -- XBT  
     XI -- XBT RADIO MESSAGE DATA   
     XS -- XBT STANDARD LEVEL   

 0617   BOTTOM HIT  
 ----   --------------------
        -- NO BOTTOM HIT
      B -- PROBE HIT BOTTOM 

NODC COUNTRY CODE

NODC PLATFORM CODE
 
NODC INSTITUTE CODE
 0606   POSITION PRECISION  
 ----   --------------------
      1 -- POSITION ACCURATE TO THE NEAREST MINUTE OF LATITUDE OR
           LONGITUDE 
      2 -- POSITION ACCURATE TO THE NEAREST TENTH OF DEGREE OF
           LATITUDE OR LONGITUDE. IF THE
           PRECISION CODE IS "2", THEN THE LATITUDE MINUTES OR
           LONGITUDE MINUTES   
           FIELD CONTAINS A TENTH OF DEGREE MEASURE
           POSITION ACCURATE TO THE NEAREST WHOLE DEGREE OF
           LATITUDE OR WHOLE DEGREE OF LONGITUDE  
      4 -- POSITION ACCURATE TO THE NEAREST TENTH OF MINUTE OF
           LATITUDE OR LONGITUDE

 0607   TIME PRECISION  
 ----   --------------------
      1 -- TIME ACCURATE TO THE NEAREST MINUTE  
      2 -- MINUTES FIELD CONTAINS A TENTH OF HOUR MEASURE   
           TIME ACCURATE TO THE NEAREST TENTH OF AN HOUR. IF THE
           PRECISION CODE IS "2", THEN THE   
           TIME ACCURATE TO THE NEAREST HOUR   

 0610   OCEAN WEATHER STATION
 ----   --------------------
      A -- ALPHA    - 62 N 33 W 
      B -- BRAVO    - 56-30 N 51 W  
      C -- CHARLIE  - 52-45 N 35-30 W   
      D -- DELTA    - 44 N 41 W 
      E -- ECHO     - 35 N 48 W 
      H -- HOTEL    - 38 N 71 W 
      I -- INDIA    - 59 N 19 W 
      J -- JULIET   - 52-30 N 20 W  
      K -- KILO     - 45 N 16 W 
      L -- LIMA     - 57 N 20 W 
      M -- MIKE     - 66 N 2 E  
      N -- NOVEMBER - 30 N 140 W
      P -- PAPA     - 50 N 145 W
      R -- ROMEO    - 47 N 17 W 
      T -- "T"      - 29 N 135 W
      V -- VICTOR   - 34 N 164 E
      X -- "V"      - 39 N 153 E

 0611   XBT PROBE TYPE  
 ----   --------------------
      1 -- 2500 FEET (XBT) SIPP T7  
      2 -- 760 METERS (XBT)SIPP T7  
      3 -- 1500 FEET       SIPP T4 OR T6
      4 -- 460 METERS      SIPP T4 OR T6
      5 -- 1830 METERS     SIPP T5  
      6 -- 200METERS       SIPP. T10
      7 -- 660 FEET        SIPP. T10
      9 -- 6000 FEET       SIPP. T5 
      A -- FAST XBT 1500 FEET (FINE STRUCTURE T11 XBT)  
      B -- FAST XBT 460 METERS (FINE STRUCTURE T11 XBT) 
      C -- 660 FEET WITH MK5 RECORDER   
      D -- ANY PROBE WITH MK8 LINEAR RECORDER   

 0612   DIGITIZATION METHOD 
 ----   --------------------
     01 -- MANUAL   
     02 -- A-D CONVERSION FROM ORIGINAL 
     03 -- A-D CONVERSION FROM COPIES   
     04 -- OPTICAL SCANNING 
     05 -- DIRECT DIGITAL OUTPUT UNKNOWN
     06 -- DIRECT DIGITAL OUTPUT BATHY  
     07 -- DIRECT DIGITAL OUTPUT SUTRON 
     08 -- DIRECT DIGITAL OUTPUT FROM SIPPICAN MARK 9   

 0613   DATA INTERVAL (XBT) 
 ----   --------------------
     01 -- FIXED INTERVAL LE 0.1 METER AND LE 0.1 DEG C 
     02 -- FIXED INTERVAL GT 1 METER BUT LE 3 METERS AND LE 0. 1
           DEG C  
     03 -- FIXED INTERVAL GT 3 METERS BUT LE 6 METERS AND LE 0 .1
           DEG C 
     04 -- FIXED INTERVAL GT 6 METERS AND LE 0.1 DEG C  
     11 -- FIXED INTERVAL LE 1 METER AND LE 0.2 DEG C   
     12 -- FIXED INTERVAL GT 1 METER BUT LE 3 METERS AND LE 0. 2
           DEG C  
     31 -- VARIABLE INTERVAL - MANUALLY DETERMINED  
     32 -- VARIABLE INTERVAL - STATISTICALLY DETERMINED 
     33 -- VARIABLE INTERVAL - PHYSICALLY DETERMINED
     FI -- XED INTERVAL GT 3 METERS BUT LT 6 METERS AND LE 0.2 
           DEG C   
    
 0614   DATA TREATMENT AND STORAGE
 ----   --------------------
     01 -- SINGLE DIGITIZATION; STORED AS DIGITIZED 
     02 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.05 DEG
           C 
     03 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.1 DEG
           C  
     04 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.2 DEG
           C  
     05 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.3 DEG
           C  
     06 -- SINGLE DIGITIZATION; COMPRESSION; FIT WITHIN 0.7 DEG
           C  
     21 -- DUAL DIGITIZATION AND AVERAGING; STORED AS DIGITIZE 
     22 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.05 DEG C 
     23 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.1 DEG C  
     24 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.2 DEG C  
     25 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.3 DEG C  
     26 -- DUAL DIGITIZATION AND AVERAGING; COMPRESSION; FIT 
           WITHIN 0.5 DEG C  

 0615   BT REFERENCE TEMPERATURE
 ----   --------------------
      1 -- BUCKET   
      2 -- INJECTION, OR UNVERIFIED BUCKET NOTATION, OR UNKNOWN 
      3 -- NANSEN CAST (REVERSING THERMOMETER)  
      4 -- THERMOGRAPH  
      5 -- SPECIAL CALIBRATION THERMOMETER OR EQUIPMENT 
      6 -- BT   
      7 -- STD  
      9 -- BLANK

 0616   UBT FILE ID 
 ----   --------------------
     M  -- MBT  
     MS -- MBT STANDARD LEVEL   
     X  -- XBT  
     XI -- XBT RADIO MESSAGE DATA   
     XS -- XBT STANDARD LEVEL   

 0617   BOTTOM HIT  
 ----   --------------------
        -- NO BOTTOM HIT
      B -- PROBE HIT BOTTOM 

NODC COUNTRY CODE

NODC PLATFORM CODE
 
NODC INSTITUTE CODE
