Progress toward acoustic volume attenuation tomography

Experiments were carried out in the eastern Pacific and north Atlantic Oceans with the purpose of estimating volume attenuation coefficients in seawater by measuring acoustic amplitude along eigenray paths in the mid-frequency regime (3-9 kHz). A quantitative comparison of the measured attenuation coefficients in three experiment sites is presented here along with a comprehensive examination of historical measurements in these areas. The ability to make precise measurements of acoustic volume attenuation coefficients has applications in detection theory, acoustic communications, and ocean sensing. A method of inverting for properties such as temperature, salinity, and pH, which influence the attenuation of sound in seawater, is discussed.