Study on Frequency and Magnitude of Lightning Strike Variations

Abstract

Lightning is a natural phenomenon that is responsible for a few billion dollars’ worth property damage hundreds of human losses yearly in worldwide. Lightning is an electrical discharge that takes place b oppositely charge regions either within a cloud or between two clouds or cloud and ground. The mentioned above is called intra cloud, which is most common type, while the second and third type ar inter cloud and ground discharges (cloud to ground), respectively. In order to understand the risk of lig particular region, proper knowledge on lightning parameters such as frequency, density, magnitude o pattern of lightning activities etc.... should be studied. Unfortunately, for such a study a lightning loca is necessary to be identified. Since there is no such system available in Sri Lanka, in this study, we studie parameters of Swedish lightning activities. In this study, more than 10.7 million of lighting records in last 15 years from 2000-2014 recorded to Lightning Detection Centres of the Lightning Location and (LLP) systems were analysed. The LLP system can provide the information such as striking locati occurrence, polarity, magnitude, and number of flashes per each strike. Wavelet Theory, Time Frequency Analysis and Range Normalization of Signal Strength (RNSS) a analyse the data. The analysis was carried out to achieve several objectives. Lighting patterns were s respect to location, periods, frequency and magnitude. In this study, it was observed that the lightning strike count increases towards the Equator. In Wavelet was revealed that every year there is a strong lightning activity period and the repeating period of this e from 0.7 to 1.4 years. Every 4.5 – 6.0 year period, the occurrence of lightning strikes has a strong rela increase its magnitude.