# Speed of sound in sea water (Mackenzie empirical equation)

## Description

The speed of sound is the distance travelled per unit of time by a sound wave propagating through an elastic medium. The speed of sound in seawater depends on pressure (hence depth), temperature (a change of 1 °C ~ 4 m/s), and salinity (a change of 1‰ ~ 1 m/s). Empirical equations have been derived to accurately calculate sound speed from these variables. One of them with reasonable accuracy for the world’s oceans is due to Mackenzie. (standard error of 0.070 m/s for salinity between 25 and 40 ppt). The speed in the ocean of sound ranges between 1400 and 1570 m/sec.

Related formulas## Variables

c | Speed of sound in sea water (m/s) (dimensionless) |

T | Temperature (degrees) (dimensionless) |

S | Salinity (ppt) (dimensionless) |

Z | Depth (m) (dimensionless) |