[M-TT37] Brand-new scope of coupling geophysics being established by infrasound and associated waves

[MTT37-P04] Trial study on relation of distance from a tornado to infrasound array station associated with tornado scale

*Makiko Iwakuni¹, Nobuo Arai¹, Takayuki Otsu¹, Masashi Motohashi¹, Yuki Takeda¹, Mami Nogami¹ (1.JAPAN WEATHER ASSOCIATION)

Keywords:infrasound, Tornado

A tornado occurred near the infrasound array site deployed in Toyohashi City, Aichi Prefecture. Damaged buildings were distributed in a belt. Based on the scale of the damage, the JMA estimated that tornado intensity is between JEF0 (the Japanese Enhanced Fujita Scale) and JEF1. Cross-correlation analysis did not show strong correlation around the tornado occurrence time investigated by the JMA. However, there was a very short-term correlated signal coming from the tornado path, we hope that this short-term correlated signal is infrasound generated by the tornado.
Bedard found out that infrasound array detect signal associated with tornadoes in the 1980's. Research about infrasound generated by tornadoes also energetically has been operated mainly in North America (ex. Frazier et al., 2014, Elbing et al., 2019). However, it is still under discussion on the mechanism how tornado generate infrasound. In order to obtain a clue to figure out this mechanism, it is significant to observe infrasound generated by tornadoes.
It is thought winds in a tornado depend on a tornado intensity and infrasound generated by a tornado associate to a tornado intensity. Existing papers, as a first step, the amplitude of infrasound generated by tornadoes seems to be attenuated over distances. We will try to investigate and introduce how far away can array site observe the infrasound of a tornado.