Observation of signals of VLF radio stations and VLF noise during the solar eclipse on March 29, 2006

Abstract

on signals of VLF radio stations, regular radio-noise intensity in the VLF range 0.3-10 kHz, and the number of atmospherics registered in Yakutsk mainly from the western direction are considered. The full lunar shadow zone consistently shaded the daytime section of the radio-signal propagation path from the western coast of Africa to Altai. A multichannel parallel analyzer-recorder (operating in the frequency range 0.47-8.7 kHz), one-point thunderstorm direction-and-range finder (0.3-100 kHz), narrow-sector radio-noise direction finder (0.3-10 kHz), recorder of VLF radio-station signals, and broadband radio-noise recorder (0.3-100 кГц) were used for observations. Time synchronization of the recorder of VLF radio-station signals was carried out with the help of GPS-clocks. The effect was observed in radio-station signals, radio-noise, and number of atmospherics from a direction of (270 ± 20)º, counted from the north clockwise, in the last stage of the eclipse (~11-12 UT), when the lunar shadow approached the night terminator and crossed the signal propagation path. The effect was manifested through a ~20% gain of the received signals, ~40% increase in the number of atmospherics, and radio-station phase changes. The registered effects are similar to those we observed during the eclipse on March 9, 1997.

The Lower Ionospheric VLF/LF Response to the 2017 Great American Solar Eclipse Observed Across the Continent

“…Da Costa et al () presented variations of the “Omega” transmitters (Swanson, ) during the 30 June 1992 eclipse over South America. Kozlov et al () examined the 29 March 2006 eclipse over Africa and Asia. Theoretical efforts have proceeded based on these measurements.…”

Modeling D-region ionospheric response of the Great American TSE of August 21, 2017 from VLF signal perturbation

“…Such changes induce perturbations in the ionosphere that in turn interfere with radio signals propagating within the Earth-ionosphere waveguide (EIWG) and gets manifested as anomalies in the received signal amplitude and phase. Solar eclipse provides an unique opportunity to study such mechanisms behind ionospheric variations as its time of occurrence is pre-determined and thus it gives chance to equip ourselves accordingly [Crary and Scheneible 1965;Mitra 1974;Sen Gupta et al 1980;Lynn 1981;Pant and Mehra, 1985;Thomson 1993;Clilverd et al 2001;Kozlov et al 2007;Karimov et al 2008;Chernogor 2010;Chakrabarti et al 2010Pal et al, 2015;Chakraborty et al, 2016]. During a solar eclipse, the Moon comes in between the Sun and the Earth for a brief period, resulting a sudden loss of solar radiation over a specific region on the Earth.…”

Spectral character of VLF sferics propagating inside the Earth‐ionosphere waveguide during two recent solar eclipses

“…It is interesting to note that very few studies have been made using VLF sferics during solar eclipses at different places and in all the cases including the present one, enhancement in intensity has been found [ De et al , 2009; Karimov et al , 2008; Mullayarov et al , 1999; Kozlov et al , 2007] but the frequency dependence of the change in VLF sferics for two different solar eclipses are yet to be explored. Kozlov et al [2007] measured the radio noise in the VLF range from 0.3 to 10 kHz during the solar eclipse on March 29, 2006 with the help of broadband recorder. He reported an overall increase of 40% of the ambient level in the average number of sferics during the solar eclipse at Yakutsk.…”

“…The Great Circle Path (GCP) distance between VLF transmitter and receiver, alignment of path with respect to geomagnetic equator and the conductivity of ground below GCP plays a vital role in determining the final variation of VLF signal at a fixed place on the Earth [ Clilverd et al , 2001]. It is interesting to note that very few studies have been made using VLF sferics during solar eclipses at different places and in all the cases including the present one, enhancement in intensity has been found [ De et al , 2009; Karimov et al , 2008; Mullayarov et al , 1999; Kozlov et al , 2007] but the frequency dependence of the change in VLF sferics for two different solar eclipses are yet to be explored. Kozlov et al [2007] measured the radio noise in the VLF range from 0.3 to 10 kHz during the solar eclipse on March 29, 2006 with the help of broadband recorder.…”