Velocity of Sound in Water
D2. Hydrography, tides, waves, bathymetry and marine geologyDefinition
Speed of sound in seawater, depending on temperature, salinity, and pressure.
The speed of sound in seawater is about 1,450 to 1,540 m/s and rises with temperature, salinity, and pressure (depth). Its vertical structure creates the SOFAR sound channel and refracts acoustic paths, so every echo-sounding, multibeam, and ADCP survey needs a measured or modeled sound-velocity profile to convert travel time to depth or range. An error of a few meters per second biases deep soundings by meters.