Relationship between median intensities of electromagnetic emissions in the VLF range and lightning activity

F Němec (1, 2, 3) , O Santolík (2) , Michel Parrot (3) , C.J. Rodger (4)

1 CAS - Czech Academy of Sciences [Prague]
2 Faculty of Mathematics and Physics [Praha/Prague]
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
4 Department of Physics [Dunedin]

[1] We present results of a survey of VLF electromagnetic waves observed by the DEMETER spacecraft (altitude about 700 km, launched in June 2004, and still operating). The median value of the power spectral density of electric field fluctuations in the frequency range 1–10 kHz is evaluated as a function of the position of the spacecraft, frequency, magnetic local time, and season of the year. It is shown that there are significant seasonal differences between the satellite observed wave intensities throughout the year and it is demonstrated that these are due to the lightning activity changes of the Earth. The frequency spectrum at frequencies 0–20 kHz of electromagnetic emissions caused by the lightning activity is investigated as a function of geomagnetic latitude. It is shown that the effect of the lightning activity is most pronounced at frequencies larger than about 2 kHz, forming a continuous band of emissions and being the strongest during the nighttime because of the better coupling efficiency of electromagnetic waves through the ionosphere. Citation: Němec, F., O. Santolík, M. Parrot, and C. J. Rodger (2010), Relationship between median intensities of electromagnetic emissions in the VLF range and lightning activity,

Domaines: Planète et Univers [physics]

F Němec, O Santolík, Michel Parrot, C.J. Rodger. Relationship between median intensities of electromagnetic emissions in the VLF range and lightning activity. Journal of Geophysical Research Space Physics, 2010, 115, A08315 (10 p.). ⟨10.1029/2010JA015296⟩. ⟨insu-01180758⟩