An investigation of the correlation of infrasound signals as a function of sensor separation and wind velocity

Wind noise is a common obstacle to the detection and analysis of infrasonic signals. The masking caused by the wind noise is often reduced by spatial averaging via pipe or porous hose arrays. An alternate method is to average the signals from multiple sensors in distributed arrays. In order to reduce the wind noise, the sensors in the distributed array must be far enough apart so that their wind noise signals are incoherent, but not so far apart that the sound loses its coherence. Few measurements have been reported of the infrasound correlation distance in the presence of wind. This paper reports results of measurements of this infrasound correlation when the infrasound sensors are separated by distances up to hundreds of meters. Techniques for combining infrasound signals from widely separated sensors and measuring their correlation in the presence of wind noise are discussed.