Initial infrasound source characterization using the phase and amplitude gradient estimator method

The phase and amplitude gradient estimator (PAGE) method for vector acoustic intensity [D.C. Thomas et al. J. Acoust. Soc. Am. 137, 3366–3376 (2015)] has been used previously to improve source characterization over broad frequency ranges. This paper describes the applications of the PAGE method in two outdoor infrasound sources characterization using multi-microphone probes. Measurements where made with a setup designed to address the challenges when dealing with outdoor infrasound sources, such as low coherence, noise contamination and microphone mismatch. Also, applying the acoustic intensity methods brings up analysis challenges including phase unwrapping above the spatial Nyquist frequency, source statistical stationarity, and balancing frequency resolution with averaging across finite record lengths. This paper describes the results of source characterization for a large rocket motor and a wind turbine using two different microphone probe setups, and how these measurement and analysis challenges performed with the probes setups.The phase and amplitude gradient estimator (PAGE) method for vector acoustic intensity [D.C. Thomas et al. J. Acoust. Soc. Am. 137, 3366–3376 (2015)] has been used previously to improve source characterization over broad frequency ranges. This paper describes the applications of the PAGE method in two outdoor infrasound sources characterization using multi-microphone probes. Measurements where made with a setup designed to address the challenges when dealing with outdoor infrasound sources, such as low coherence, noise contamination and microphone mismatch. Also, applying the acoustic intensity methods brings up analysis challenges including phase unwrapping above the spatial Nyquist frequency, source statistical stationarity, and balancing frequency resolution with averaging across finite record lengths. This paper describes the results of source characterization for a large rocket motor and a wind turbine using two different microphone probe setups, and how these measurement and analysis challenges perf...