Sonar calculator algorithms

This page details the algorithms used in Sonar Calculator.

Where:

c = speed of sound (m/s),

α =  absorption coefficient (dB/m)

T = temperature (°C)

S = salinity (ppt)

D = depth (m)

f = frequency (kHz)

Speed of sound in salt water (Mackenzie, 1981)

where  -2 < T < 30

25 < S < 40

0 < D < 8000

Speed of sound in salt water (Leroy, 1969)

where -2 < T < 23

 30 < S < 40

 0 < D < 500

Speed of sound in fresh water (Del Grosso and Mader, 1972)

where  0 < T < 95

  D = 0

Absorption coefficient (Francois & Garrison, 1982)

where:

This algorithm applies to all oceanic conditions and 200 Hz < f < 1 MHz.

Note: The Francois & Garrison (1982) algorithm calculates the absorption coefficient in units of dB/km. Echoview displays the calculated absorption coefficient units in dB/m as recommended by MacLennan et al (2002).

See also

About Sonar Calculator
Sound speed references