The radiation of atmospheric microbaroms by ocean waves

A two-fluid model, air over seawater, is used to investigate the radiation of infrasound by ocean waves. The acoustic radiation which results from the motion of the air/water interface is known to be a nonlinear effect. The second-order nonlinear contribution to the acoustic radiation is computed and the statistical properties of the received microbarom signals are related to the statistical proper-ties of the ocean wave system. The physical mechanisms and source strengths for radiation into the atmosphere and ocean are compared. The observed ratio of atmospheric to oceanic microbarom peak pressure levels (approximately 1 to 1000) is explained. (c) 2006 Acoustical Society of America.