EFFECT OF SQUALLS AND WIND GUSTS ON FLUCTUATIONS OF AMBIENT OCEAN NOISE

The effect of wind irregularities on fluctuations of the spectral comp onents of ambient sea noise is analyzed. Experimental examples are use d to demonstrate that the parameters of the noise envelope depend on t he relation between the spatial scales of wind disturbances and the si ze of the hydrophonically covered region on the sea surface. A conveni ent noise-field modeling concept of a radial function of hydrophone se nsitivity to distributed surface dipole noise sources is introduced. T his hydrophone surface sensitivity function (SSF) depends on the sound velocity profile, hydrophone submersion depth, frequency-dependent ab sorption in the medium, bottom reflectivity, and scattering of sound i n the bulk and from the boundaries of the waveguide. The characteristi cs of noise fluctuations are determined by convolving the SSF with a m oving mosaic of wind gusts. It is demonstrated that the SSF integrates small-scale wind gusts, and the dimension of the averaged surface flu ctuations of wind speed are greater the deeper the hydrophone. Experim ental results proved the adequacy of the noise-field fluctuation model built around the SSF. It is demonstrated that the wind speed, locally measured above the point of sound measurement, need not always define the level of noise and parameters of its fluctuations.