A data bank of outdoor transfer functions
* Presenting author
From the viewpoints of sound sensing and noise pollution applications, the propagation channel can be modeled by a transfer function. This transfer function is a sort of Grail, which readily connects any near-field signature to its propagated counterpart. In the scenario of outdoor propagation above a flat ground, the atmospheric conditions vary, and a data bank of transfer functions is needed. This study addresses the computational and physical challenges of forming such a data bank. It uses a three-dimensional, Finite-Difference, Time-Domain (FDTD) solver for propagating a reference wideband signal at 200 m above a finite-impedance ground. The simulations span over a wide range of meteorological conditions with consistent turbulence realizations. The formed transfer functions are compared to recent atmospheric-acoustic measurements. Their sensitivity to the wind direction and strength is discussed. The data bank is unique in its extensiveness and physical realism, and can be used for applicative purposes.