Mapping Ocean Winds by Broadband Acoustic Interferometry

Mapping the wind over vast ocean areas is a very important practical problem, especially at high winds. Satellite measurements using scattering of electromagnetic waves from the rough ocean surface are extremely useful; however, the cross section for this scattering saturates at high winds, when wind speed measurements are most valuable. On the other hand, the same mechanism that precludes use of satellites for the purpose of measuring ocean surface winds may allow measurements via underwater acoustic techniques. Surface wind is one of the most significant contributors to the ocean ambient noise field, and level of the wind-generated noise strongly depends on the wind speed. Using measurements of the ocean ambient noise for wind retrieval was suggested long ago (work [1] was, probably, one of the first where this approach was systematically considered.) Recently this idea was revisited in conjunction with the necessity to accurately estimate wind speed in the hurricanes [2]. Work [2] provides also rational for using acoustical means for solution of this important problem.