5:15 PM - 6:30 PM
[MTT43-P03] Atmospheric wave energy of the 2020 August 4 explosion in Beirut, Lebanon, from ionospheric disturbances
The electron distribution in the ionosphere is often disturbed by various phenomena in the atmosphere. They are observed as changes in TEC (Total Electron Content) along line-of-sight connecting GNSS (Global Navigation Satellite System) satellites and receivers. For example, large meteorites entering the Earth’s atmosphere often explode and are recognized as fireballs. Sound waves and internal gravity waves excited by them propagate through the atmosphere, reach the ionospheric F region, and disturb TEC. A fireball appeared near Chelyabinsk, Russia, on February 15, 2013, one of the largest fireball events in the observation history, made significant disturbance signals in TEC observed with multiple GPS satellites and ground receivers.
Here I report ionospheric disturbances following the chemical explosion that occurred in Beirut, Lebanon, on August 4, 2020 using nearby continuous GNSS stations. The scale of this explosion is 1-1.5 kt (TNT), which is about 1/100 of the fireball over the Bering Sea. Despite its small scale, N-shaped TEC changes were observed thanks to the existence of a dense continuous GNSS station network to the south of Beirut. The signals were found only at southern stations with distances >200 km from the explosion site, which is due mainly to the interaction of ionospheric electrons with the magnetic field.
Currently, we also perform a numerical simulation study of the propagation of disturbances excited by the explosion. In the simulation, we assumed the sound velocity structure in the atmosphere (US Standard Atmosphere 1976), the Chapman-type altitude dependence of electron density, and the influence of the magnetic field, and simulated the upward propagation of N-shaped sound waves. As a result, N-shaped TEC changes that match the observed waveforms could be reproduced. In the future, we plan to sort out following problems in this numerical simulation, (1) the waveform cannot be reproduced for line-of-sight penetrating the region just above the explosion, (2) propagation in the east-west direction is not sufficiently considered, and (3) objective determination of the optimum period of the disturbance.
Here I report ionospheric disturbances following the chemical explosion that occurred in Beirut, Lebanon, on August 4, 2020 using nearby continuous GNSS stations. The scale of this explosion is 1-1.5 kt (TNT), which is about 1/100 of the fireball over the Bering Sea. Despite its small scale, N-shaped TEC changes were observed thanks to the existence of a dense continuous GNSS station network to the south of Beirut. The signals were found only at southern stations with distances >200 km from the explosion site, which is due mainly to the interaction of ionospheric electrons with the magnetic field.
Currently, we also perform a numerical simulation study of the propagation of disturbances excited by the explosion. In the simulation, we assumed the sound velocity structure in the atmosphere (US Standard Atmosphere 1976), the Chapman-type altitude dependence of electron density, and the influence of the magnetic field, and simulated the upward propagation of N-shaped sound waves. As a result, N-shaped TEC changes that match the observed waveforms could be reproduced. In the future, we plan to sort out following problems in this numerical simulation, (1) the waveform cannot be reproduced for line-of-sight penetrating the region just above the explosion, (2) propagation in the east-west direction is not sufficiently considered, and (3) objective determination of the optimum period of the disturbance.