The ship continuously measured the Conductivity and Temperature of the sea water at the keel level (3.50m) by pumping it to the recording room to ANDERAA sensors and recorded on the NAVPRO navigation software at the selected sampling rate (minimum 1 sample/minute). The conductivity data were transformed to salinity by the WHOI/UNESCO Oceanographical routines. A rough control with some CTD data evidenced offsets, that were summed to the values used for the calculation of the speed of sound at the Multibeam Sonar (0.6 PSU).
A better analysis was done later during the survey, taking into account previous cruise data (MEDGOOS9, Oct. 2004, 60 CTD stations). A marked offset was evidenced for the Conductivity value, whilst the Temperature values fitted well on the curve. The regression statistics led to the equation Ca = 0.9244 Cc + 3.1056, where Ca is the value read from the ANDERAA, and Cc is the reference.