Comparison of Infrasound Wind Filter Designs

Abstract:

Infrasound arrays record the ambient acoustic field which contains not only the signals of interest but also coherent and incoherent noise. As infrasound monitoring moves beyond traditional high energy and low frequency (0.0002 up to 20 Hz) explosive sources to lower energy and higher frequency (up to ~50 Hz) sources, such as ground and air vehicles, impulsive, and steady state sources, new installation strategies for infrasound arrays may be needed. Optimum arrays to capture these signals may have shorter source-to-receiver spacing as well as closer array element spacing thereby pushing array deployments from quiet environments into complex noise and propagation environments typical of urban settings. There is a need to evaluate wind filter designs in these complex environments in order to understand how to adapt array designs. This presentation focuses on data analysis from two wind filter designs installed in the urban environment by quantifying the noise, the amplitude, and the phase effects of the filters on impulsive signals. The results provide insight into the wind filter’s effectiveness at mitigating non-acoustic noise and enhancing signals of interest.

Permission to publish was granted by the Director, Geotechnical and Structures Laboratory.