Range of validity

Equation  of Thorp is used only in the following conditions. The parameter except the frequency is not considered.

T  = 4 °C

S  = 35 ppt

D = 1 km

Francois and Garrison estimate their model to be accurate to within about 5%.

For frequencies of 10-500 kHz (where the MgSO₄ contribution dominates), the limits of reliability are:

-2 < T < 22 °C

30 < S < 35 ppt

0 < D < 3.5 km

At frequencies greater than 500 kHz, the pure water contribution exceeds that of MgSO₄, and the limits are:

0 < T < 30 °C

0 < S < 40 ppt

0 < D < 10 km

The Ainslie and McColm formula retains accuracy to within 10% of the Francois and Garrison model between 100 Hz and 1 MHz for the following range of oceanographic conditions:

-6 < T < 35 °C	(S = 35 ppt, pH=8, D = 0 km)
7.7 < pH < 8.3	(T = 10 °C, S = 35 ppt, D = 0 km)
5 < S < 50 ppt	(T = 10 °C, pH = 8, D = 0 km)
0 < D < 7 km	(T = 10 °C, S = 35 ppt, pH = 8)