A directional spectrum evolution model for wind-generated ocean noise

Traditionally, wind-generated ocean noise has been described empirically as a frequency spectrum with parametric dependence on measurement depth and local wind speed. In contrast, wind-generated noise is described and modeled here as a slowly varying directional spectrum that is excited at the sea surface by a continuum of dipole radiators and whose subsurface structure is constrained by a radiation transport equation. An empirical model of the spectral density in frequency of downward propagating wind-generated noise is used to initialize the model. Directional spectra computed using a ray-based algorithm to solve the radiation transport equation are presented which illustrate sensitivity to receiver location, ocean sound speed structure, seafloor bathymetry, and geoacoustic bottom parameters.