Observation of ocean surface scattering in the deep ocean using a towed array

Over the course of an experiment in the northern Philippine Sea in 2009, weather and sea surface conditions varied from calm and smooth to stormy and very rough. A ship with an acoustic source deployed at 15 and 60 m held station while a second ship towed Penn State's Five Octave Research Array (FORA) at 120 m depth in an arc, maintaining constant range at the first convergence zone. With the source and receivers so near the ocean surface and with zero closing speed, these events offer an opportunity to extract information about the acoustic waves' interaction with the temporally varying ocean surface. Additionally, the FORA was towed at various depths in a star pattern about the stationary source ship, and a vertical acoustic array was deployed near the source ship. Using meteorological data and a model for ocean waves given weather conditions and fully developed seas, these events offer an opportunity to separate in the data-adaptive beamformer output the arrivals scattered and Doppler shifted by the ro...