Seawater Acoustic Absorption Calculator

SEAWATER_ABSORPTION returns absorption (dB/m) of seawater of salinity ~35 ppt, given the following inputs (can be arrays):

f = frequency (Hz)
T_C = temperature (°C) valid range: 0 <= T_C <= 30
P_atm = hydrostatic pressure (atm) valid range: 1 <= P_atm <= 400

Source: Kinsler, Frey, Coppens, and Sanders. Fundamentals of Acoustics, 3rd Ed. Pages 158 through 160. Model reprinted from Fisher and Simmons. J. Acoust. Soc. Am 62, 558, 1977.

Accurate within 2%, according to KFCS.
Coded up by Chad Greene, August 2012.

EXAMPLE: Recreate Fig. 7.5 of KFCS:

freq = 100:1000000; % frequency in hertz
a = seawater_absorption(freq,5,1);
loglog(freq,a)
ylabel('absorption coefficient (dB/m)')
xlabel('frequency (Hz)')