Comparison between computed and measured beam ambient noise

Ambient noise at low frequency (20 ⩽ f ⩽ 120 Hz) has been modeled using a discrete source, Monte Carlo program (SIAM). The statistics of ambient noise levels in the beam of a horizontal array have been computed for a specific case (beamwidth = 15°) where a survey of surface ships together with measured transmission loss provided the inputs to the model. These computed results are compared to data from a horizontal array taken at the same time and at the same location as the propagation data. Results from the two methods are in quantitative agreement, indicating that this method of beam noise prediction is valid. [Work supported by ONR.]