
                  SEAS IV   - XBT File Data Format

The Shipboard Environmental (data) Aquisition System (SEAS), is a program 
developed by National Oceanic and Atmospheric Administration (NOAA) to provide
accurate meteorological and oceanographic data in real time from ships at sea 
through the use of satellite data transmission techniques. The system transmits
data through either the GOES or INMARSAT C satellites to NOAA for use in 
weather, climatological and ocean models. This SEAS IV XBT file is the Delayed-mode 
version of the copy transmitted through the satellite and placed onto the GTS as a
BATHY message.
NOAA is actively participating in an international effort to increase the 
number of subsurface temperature observations in support of global 
oceanographic and climate studies. NOAA's XBT program (SEAS) currently supports
about eighty voluntary observing ships (VOS).

For additional information, http://seas.amverseas.noaa.gov/seas/
 

 Field Name             Field Description
 
 SEAS Version:          SEAS Shipboard software version number 

 Drop:                  Sequential Number assinged for the Probe dropped during data collection
 
 Probe Type:            Type of XBT probe used (4-7,10,11) 
                        blank if entry not used.

 Code:                  XBT Instrument Code (WMO Code 1770) for temperature                 

 Equation:              Fall Rate Equation Coefficients for XBT (WMO Code Table 1770)

 Recorder:              Type of Recorder used for collecting temperature data

 Code:                  Recorder Code (WMO Code 4770)

 Launcher height:       Height of the XBT launcher above the water (meters)


 Date/Time:             Date (dd/mm/yyyy) of XBT drop (GMT)

 Latitude:              (ddd.ddd) Decimal degrees, hemisphere N=north, S=south

 Longitude:             (ddd.ddd) Decimal degrees, hemisphere E=east, W=west




 Ship:                  Ship's Name

 Cruise:                Cruise ID, example: AX70903, (TWI line AX7, year 2009, month 03)



 Call sign:             Ship's Radio Callsign. Used to identify the ship from which the data is transmitted

 Bottom Depth:          Bottom Depth (meters)


 Transmitter:           Satellite Transmitter and Data Collector
 

 Mode:                  Data is saved for Transmission as Binary or Ascii
 
 Code:                  Tranmitter Code  (N/A)

 Sea Surface Temp Type:  Type of sensor used to acquire sea surface temperature.

 Code:                   Codes for "Method of sea-surface measurement", 
                         see Codes below

                         00    Ship intake
                         01    Bucket
                         02    Hull contact sensor
                         03    Reversing thermometer
                         04    STD/CTD sensor
                         05    Mechanical BT
                         06    Expendable BT
                         07    Digital BT
                         08    Thermister chain
                         09    Infrared scanner
                         10    Microwave scanner
                         11-14 Reserved
                         15    Missing

 Value:                 Sea Surface Temperature (deg. C)
 
 Depth:                 Average depth of temperature sensor below sea surface (meters)
                        


  
 INFPTS:                Total number of Inflection Points, followed by 
                        the data record. (depth,temp) 
                        temperature values (to hundredths of a degree celsius)
                        depths (meters to tenths)
 

 XBT:                   Total number of Temperatures Points, followed by the
                        data record. Depths of each sample are not saved 
                        because they can be computed by knowing the sample 
                        number and probe type.


Either Method below can be used to Calculate depths.

Method 1:
  H=A*T-B*T**2 (meters)

  T = Time step; 0.1,0.2 ....time  : time=0.1(# of data points)
  A and B are the constants determined from the following table:

   Probe   XBT
   Code    Probe
   WMO1770 Type       B         A

   061     T-10    .00216    6.301
   071     T-11    .0002557  1.7779
   001     T-4     .00216    6.472
   002     T-4     .00225    6.691
   011     T-5     .00182    6.828
   031     T-6     .00216    6.472
   032     T-6     .00225    6.691
   041     T-7     .00216    6.472
   042     T-7     .00225    6.691
   021     T-FD    .00182    6.346
   051     T-DB    .00216    6.472
   052     T-DB    .00225    6.691

===========================================
Method 2:
 The depth is calculated from coefficients a and b and the
 time, t, as follows:

     z = at + 10-3bt2   or z = a*t + 0.001*b*t*t

      Probe  Probe               Coefficient a    Coefficient b
      Code   Type
       001  Sippican T-4            6.472         -2.16
       002  Sippican T-4            6.691         -2.25
       011  Sippican T-5            6.828         -1.82
       021  Sippican Fast Deep      6.346         -1.82
       031  Sippican T-6            6.472         -2.16
       032  Sippican T-6            6.691         -2.25
       041  Sippican T-7            6.472         -2.16
       042  Sippican T-7            6.691         -2.25
       051  Sippican Deep Blue      6.472         -2.16
       052  Sippican Deep Blue      6.691         -2.25
       061  Sippican T-10           6.301         -2.16
       071  Sippican T-11           1.7779        -0.2557
       201  TSK T-4                 6.472         -2.16
       202  TSK T-4                 6.691         -2.25
       211  TSK T-6                 6.472         -2.16
       212  TSK T-6                 6.691         -2.25
       221  TSK T-7                 6.472         -2.16
       222  TSK T-7                 6.691         -2.25

==============================================

THE ACTUAL DATA LOOKS AS FOLLOWS:

 SEAS Version 4.54  Drop 016  Probe Type Sippican Deep Blue  Code 05 Equation 2
 Recorder SIPPICAN MK-12                        Code 05  Launcher height 35.0 M
 Date/Time 18/09/2003 07:46 GMT  Latitude  20 32.8 N     Longitude 131 59.0 W
 Ship TAUSALA SAMOA                    Cruise
 Call sign V2FA2                       Bottom depth  1543476 M
 Transmitter UNKNOWN                   Mode UNKNOW Code 00
 Sea Surface Temp Type Ship Intake           Code 00 Value 99.9 C   Depth 1.0 M



INFPTS 4
   20 2487  490 2471  540 2322  700 2167

XBT 119
24812485248724872487248624862486248624862485248624852486248524862485248524862486
24852486248524862485248524852486248524852486248524852483248324822482248224822482
24802479247724772477247624762478247724752474247424712470247024702469246924702471
24712472247224712472247224712471247124722471247124712470244624112384236623502337
23212313230622982291228222762272227022612254224922452238223322282220221122022194
2198218821772173216721612156218022782325218123042388268425282179212221183126

