Equations for material absorption in the water column are summarized by Urick[53]. A somewhat standard form due to Thorpe is:

where **f** is the frequency in kilohertz and is in units of
dB/m. Attenuation in sediments is somewhat more complicated and must be
specified directly.

Material absorption is included by adding an imaginary part to the sound speed so that . Typically, the attenuation is specified in more physical units so it is necessary to perform a conversion. In the following subsections we present the results for various cases.

Tue Oct 28 13:27:38 PST 1997