The effect of bottom properties in acoustic distance measurement on the shallow water Arctic shelf

The impact of seabed characteristics on the accuracy of determining the distance between a sound source and receiver located underwater was studied within the framework of numerical experiments. Experimental data on bottom parameters and the sound speed profile in the water layer in summer and winter (hydrological) seasons in the shallow water part of the Kara Sea were used. In the latter case, the action of ice cover was taken into account. It has been found that the main error in determining the distance in the interval of 1–10 km is associated with the multimode (multiray) nature of the propagation of acoustic waves in the sound channel between the water surface and the bottom. It has been demonstrated that this error decreases to several meters in the summer and with a water-like bottom, when the sound speeds in the water layer and in the bottom are close to each other. It has been noted that horizontal refraction of acoustic waves caused by transverse inhomogeneity of the bottom also leads to errors in determining the distance, although to a lesser extent.