Measurement of the Doppler shift in forward-scattered waves caused by moderate sea surface motion in shallow waters

A study of the impulse response of the acoustic channel in shallow waters is presented with respect to space, time, and frequency shift over a time window of two hours. A broadband chirp (42–54 kHz) and a narrow band sine wave (58 kHz) are transmitted from a static source located at 51 and 166 m from a vertical line receiver array. In 20 m of water with 0.4 m of wave height, an average Doppler shift of 20 Hz is measured at 51 m range, and 10 Hz at 166 m range, due to the sea-surface motion.