Ocean and model measurements of underwater acoustic scattering functions

A series of measurements of the joint Doppler shift and delay (the scattering function) of surface scatter have been made under controlled conditions. Two series of experiments were conducted, one in the Pacific ocean and one in the model tank facility at Yale. The measurement technique in both cases was the use of a time series of probing pulses [J. G. Zornig, J. Acoust. Soc. Am. 64, 1492–1499 (1978)] to extract fading time series data over a wide signal bandwidth. The result of an analysis of these data indicates a statistical relationship between frequency spread and relative arrival time which is not in agreement with previously reported theoretical results [F. B. Tuteur and J. F. McDonald, J. Acoust. Soc. Am. 57, 1025–1029 (1978)]. The ocean and tank data are in substantial agreement and examples of a test of the data acquisition and analysis system, using solid moving targets, are presented as confirmation of method. [Work supported by NSF and MPL, Scripps.]