Infrasound characteristics of nontornadic and tornadic thunderstorms using high-resolution simulations

Abstract

There has been increased interest in improving severe weather detection by supplementing NOAA's WSR-88D radar network with an infrasound observation network, which may be able to detect distinct sub-audible signatures from tornadic thunderstorms. While there is evidence that tornadic thunderstorms exhibit observable infrasound signals, what is not well-understood is whether these infrasound signals are unique to tornadic storms compared to nontornadic storms or whether there is any useful signal prior to tornadogenesis (which would be most relevant to NWS forecasters). In this presentation, we will present the results of high-resolution simulations of severe thunderstorms, specifically tailored to represent acoustic wave propagation with frequencies of 0.1 to 1 Hz. The spectral analysis of pressure perturbations generated by a nontornadic and tornadic supercell thunderstorm will be compared against each other. Two additional sensitivity tests that employ different microphysics schemes (i.e., the representation of precipitation within the storm) will be discussed, since prior work has indicated that the melting of precipitation is a dominant contributor to infrasound generation in thunderstorms. So far, preliminary results suggest that there are no discernible differences in infrasound observed in the vicinity of tornadic versus nontornadic supercell thunderstorms prior to tornadogenesis.