Severe Storm and Tornadic Infrasound Observations from the IRIS USArray

Tornado-producing storms have been observed to emit infrasound, sound at frequencies below 20 Hz, up to two hours before tornadogenesis. Due to low atmospheric attenuation of low frequency, infrasound may be detected over large distances. If the received signals can be correlated with storm and/or tornado properties, passive infrasound monitoring could improve and augment the monitoring and/or prediction of severe weather. Previously, our team has focused on observations from a stationary array and a mobile array deployed near weather radar. To improve our database of observations, we have mined the available infrasound data from the IRIS Transportable Array (TA), which consisted of a grid of several hundred broadband seismographs that traversed the continental United States from 2003 to 2016. The widespread use of infrasound sensors on stations began in 2011. Given the high number of tornadoes from 2011 to 2016, the TA provides an untapped vein of infrasound recordings of severe storms. Within the present work, infrasound recordings from TA stations during several events will be presented alongside radar and local atmospheric conditions. These recordings will be considered within the light of potential mechanisms for tornado infrasound proposed in previous literature.