Ionospheric Effects of the Kamchatka Meteoroid: Results of GPS Observations

Abstract

The most important event in astronomy and celestial physics in the early 21st century is the fall of the Chelyabinsk meteoroid with a kinetic energy of nearly 440 kt TNT. Such an event occurs once every 65 years on average. The effects of this celestial body are considered in more than 200 scientific papers. At the same time, less than 25 papers are devoted to the fall of another large meteoroid called the Kamchatka meteoroid on December 18, 2018, at 23:48:20 UT (Universal time). Meanwhile, the parameters of this meteoroid are quite unique. The velocity components are v_x = 6.3, v_y = –3, and v_z = –31.2 km/s, and the velocity magnitude was 32 km/s. The total optical radiated energy was E_r = 1.3 × 10¹⁴ J (31 kt of TNT), the fireball explosion altitude was z_r = 26 km, and the coordinates are 56.9° N, 172.4° E. The angle of entry into the atmosphere with respect to the horizon was close to 68.6°. The meteoroid had the initial kinetic energy of 173 kt of TNT, the mass of 1.41 kt, and the size of nearly 9.4 m. The fall of such bodies occurs at a frequency of once every 30 years. It is of interest to perform the further study of its ionospheric effects and compare the results measured by ground-based and satellite methods with each other. The objective of this study is to analyze the results of GPS observations for the ionospheric effects to compare them with the results measured by the method of ground-based oblique incidence sounding of the ionosphere. To observe the ionospheric disturbances following the fall of the Kamchatka meteoroid, an AC60 receiving station (geographic coordinates, 53° N, 173° E) located at a distance of 450 km from the Kamchatka meteoroid explosion site and six GPS satellites (PRN02, PRN05, PRN07, PRN09, PRN29, and PRN30) were used. The principal results of these studies are the following. GPS technologies were used to estimate the delay times of ionospheric response to the Kamchatka meteoroid explosion, the horizontal propagation velocities of disturbances (504–520 m/s) and their periods (11–18 min), durations (22–35 min), wavelengths (333–530 km), and the relative amplitudes of electron density disturbances (3–4%). The estimate obtained for the relative amplitudes of wave disturbances in the electron density by the ground-based and satellite methods have proven to be close to each other (3–4%). Their periods also have close values (10–15 min). The ground-based and satellite methods also revealed the wave disturbances associated with both atmospheric gravity and seismic waves.