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We present a new method for identifying the source regions of lightning generated whistlers observed at a fixed location. In addition to the spatial distribution of causative lightning discharges, we calculate the transmission ratio of lightning discharges into ground detectable whistlers as a function of location. Our method relies on the time of the whistlers and the time and source location of spherics from a global lightning database. We apply this method to whistlers recorded at fifteen ground based stations in the AWDANet (Automatic Whistler Detector and Analyzer Network) operating between 2007-2018 and to located lightning strokes from the WWLLN (World Wide Lightning Location Network) database. We present the obtained maps of causative lightning and transmission ratios. Our results show that the source region of whistlers corresponding to each ground station is around the magnetic conjugate point of the respective station. The size of the source region is typically less than 2000 km in radius with a small fraction of sources extending to up to 3500 km. The transmission ratio is maximal at the conjugate point and decreases with increasing distance from it. This conforms to the theory that whistlers detected on the ground propagated in a ducted mode through the plasmasphere and thus the lightning strokes of their causative spherics must cluster around the footprint of the ducts in the other hemisphere. Our method applied resolves the whistler excitation region mystery that resulted from correlation-based analysis methods, concerning the source region of whistlers detected in Dunedin, New Zealand., 22 pages, 10 figures, submitted to Journal of Geophysical Research, Space Physics

The lightning localization task is very interested for the meteorologist organizations, airlines, networks operators, military and etc. The electromagnetic properties of lightning can be measured using VLF sensor. The paper deals with some hardware and software of VLF sensors used in IKIR FEB RAS.

Experimental observations of whistlers carried out in July, 2011, at the Paratunka observatory (53.02° N, 158.65° E; L = 2.3) and coinciding in time with experiments in the scope of the HAARP project (62.30° N, 145.30° W; L = 4.2) made it possible to discover their nonstandard shape, which is most probably caused by amplitude-modulated electromagnetic pulses with a duration of about 1 s and a basic frequency of ≈ 1.1 kHz.

Topical problems of monitoring and analysis of lightning activity are considered. The paper also presents monthly distributions of lightning discharges over the globe. The instrumentation applied in VLF signal registration is described. An algorithm of search for possible areas of lightning activity affecting whistler occurrence in a defined region is suggested. The algorithm compares each detected whistler with the data of the World Wide Lightning Location Network. It also may be used to analyze different time intervals of the world lightning activity from the moment of whistler formation.