This guide provides current information and equations for calculating the speed of sound in sea-water as a function of temperature, salinity and pressure (or depth).

Contents

	Two simplified equations are those derived by Mackenzie and Coppens.
	UNESCO equation: Chen and Millero
		The international standard algorithm, recalculated following the adoption of the International Temperature scale of 1990.
	Del Grosso's equation
		Preferred to the UNESCO equation by some researchers, also recalculated following the adoption of the International Temperature scale of 1990.

Also available:

• Pressure or Depth: Converting from pressure to depth or from depth to pressure.
• Uncertainties: Advice on the accuracy and precision of the various equations.
• References: Up-to-date list of references on sound speed in sea-water.

For further information, contact Justin Ablitt.