Absorption of sound in sea-water

Laboratory and field data on the absorption of sound in sea- water are reviewed in the light of modern theory, including effects of pressure, temperature and salinity. The effects of temperature and MgSO4 salt concentration appear to be compatible from one investigator to another. There is some dispute, however, about the absolute value of the coefficient. The pressure effect has been measured for pure water, but has not been applied to the ocean as far as the authors know. The importance of this pressure effect on bottom loss measurements is shown to be sizable. An expression is presented for sound absorption in sea-water as a function of frequency, temperature, pressure and salt concentration.