Day‐to‐day variation of the angular distribution of lightning activity calculated from ELF magnetic measurements

We study the “local” distribution of lightning activity on the Earth calculated from Extremely Low Frequency (ELF) magnetic field variations. Lightning generates strong electromagnetic impulses recorded in the ELF band as short signal spikes. Using two perpendicular magnetic antennas at our Hylaty station, we calculate the azimuths of the sources of such spikes. These ELF data are compared with selected satellite measurements available on NASA and BADC web centres. For the winter period January 8 to 9, 2006, analysed in detail, a large cyclone was observed over the Mediterranean Sea (MS). The cyclone was created in the western part of the MS and then moved eastwards along the North coast of Africa. The absence of lightning activity nearer our station allowed us to compare the ELF measurements with observations of this cyclone made from the TRMM and Meteosat‐7 satellites, using Lightning Imaging Sensor observations and full Earth disk images, respectively. The analysis proves that ELF measurements can be used for on‐line monitoring of lightning activity in the vicinity of the measuring ELF station, with the radius of effective observations being more than 2000 km. This inexpensive method can easily be used in areas without other lightning monitoring systems, or it can supplement existing ones.