Effect of time‐varying tropospheric models on near‐regional and regional infrasound propagation as constrained by observational data

Abstract

The Chulwon Seismo‐Acoustic Array (CHNAR) is a regional seismo‐acoustic array with co‐located seismometers and infrasound microphones on the Korean peninsula. Data from forty‐two days over the course of a year between October 1999 and August 2000 were analyzed; 2052 infrasound‐only arrivals and 23 seismo‐acoustic arrivals were observed over the six week study period. A majority of the signals occur during local working hours, hour 0 to hour 9 UT and appear to be the result of cultural activity located within a 250 km radius. Atmospheric modeling is presented for four sample days during the study period, one in each of November, February, April, and August. Local meteorological data sampled at six hour intervals is needed to accurately model the observed arrivals and this data produced highly temporally variable thermal ducts that propagated infrasound signals within 250 km, matching the temporal variation in the observed arrivals. These ducts change dramatically on the order of hours, and meteorological data from the appropriate sampled time frame was necessary to interpret the observed arrivals.