Natural ELF/VLF atmospheric noise statistics in the eastern Mediterranean

Very Low Frequency (VLF; 3-30 kHz) and Extremely Low Frequency (ELF; 3-3000 Hz) electromagnetic transient signals and noise are generated by various natural and anthropogenic processes. On a global basis by far the most significant source is ELF/VLF radiation from lightning propagating in the Earth-ionosphere waveguide. This atmospheric "noise", originating essentially from lightning discharges, is the main source of interference for VLF/LF telecommunications. One of the statistical measures that are used to define the properties of low-frequency radio noise is the voltage deviation Vd, being a measure of the impulsiveness of the noise, which is widely used to characterize radio noise, particularly in the International Radio Consultative Committee (CCIR) reports. For the first time we present analysis of the statistical parameters of Vd from continuous broadband VLF measurements for a period extending more than one year.