Physical parameters for four seabed geoacoustic models from low-frequency measurements

Low-frequency (LF) sound speed and attenuation in sandy/silty seabottoms have recently been analyzed and summarized from long-range field measurements in shallow water [Zhou, Zhang and Knobles, J. Acoust. Soc. Am., 125, 2847-2866, 2009]. Field measurements conducted at 20 locations in different coastal zones around the world were analyzed. The seabed attenuations, inverted from different acoustic field characteristics, exhibit similar magnitude and nonlinear frequency dependence below 2000 Hz. The present paper shows that both LF field-derived sound speed and attenuation in the bottom can be equally well described by the Biot-Stoll model, the Buckingham VGS model, the Chotiros-Isakson BICSQS model, and the Pierce-Carey model. Possible ranges of the physical parameters for each of these four seabed acoustic models are estimated based on the LF field-inverted sound speed and attenuation. These four models with different physical mechanisms in consideration may result in almost identical nonlinear frequency dependence of sound attenuation in sandy/silty seabottoms.