A specialized CT sensor for real-time input of sea-surface sound speed to a multibeam echo-sounder

The accuracy of a wide swath multibeam echosounder depends in part on continuous and accurate determination of the speed of sound at the transducer arrays. To provide the accurate temperature and salinity measurements required to compute the surface sound speed aboard SIOs R/V Melville, a stand-alone system was developed that interfaces to conductivity and temperature sensors and continuously computes and broadcasts salinity and sound speed data for collection by the multibeam echosounder and shipboard computer server. The design, operation, and calibration of this system aboard Melville are discussed and samples of data collected during a recent expedition are examined