Calculated Sound Speed
>> Calculating sound speed from XBT temperature profiles

>> Climatology assisted versus standard salinity value

  Calculating sound speed from XBT temperatures is a standard procedure. This typically involves setting a particular fixed value of salinity to be used in the calculations, usually 35 psu. This assumes salinity deviation will not lead to unacceptable sound speed errors.

Turo XBT software uses advanced algorithms to extract a salinity profile from the climatology database - a salinity profile for the given latitude and longitude and for the given seasonal time of year. This salinity profile is then used with the XBT temperature profile to derive a sound speed profile.

Operator selectable options enable either climatology assisted or standard fixed value calculations.

The following clearly illustrates the potential improvements. In this example at 200 metres depth the standard method is improved upon by >1 m/sec and possible distortion is improved over the whole profile.


New Advanced
Climatology Assisted
Calculated Sound Speed
sound speed calculation uses
salinity from climatology
sound speed calculation uses
fixed salinity set to 35 psu
difference between between standard method
and climatology assisted method