Ukrainian segment of the ENTLN (LIGHTNING FINDING SYSTEM)

Abstract

The Ukrainian segment of the Earth Networks lightning finding system created in 2016 is dis-cussed in the paper. It consists of 12 sensors located in different parts of Ukraine which allow identifying both types of lightning: "cloud-to-ground discharge (CG)" and "cloud-to-cloud dis-charge (CC)". The stated number of sensors covers the entire territory of Ukraine and allows the determination of CG with a probability of 95 % with the spatial accuracy of lightning detection constituting about 200 meters. Taking into account the necessity to preserve the equipment, an agreement was reached with the Ukrainian Hydrometeorological Centre on installation of light-ning finding sensors within the territory of meteorological stations. Significant advantage of this lightning finding system is that it allows recording of electromagnetic lightning signals within the range from 1 Hz to 12 MHz. Due to this, the spatial position of CG and CC can be determined more accurately by analyzing the spectrum of electromagnetic signal within the specified range. To localize a lightning discharge using the ENTLN network the method of lightning finding based on the principle of "time of signal arrival (ToA)" is applied. The primary data obtained from the lightning finding sensors are analyzed in the internal system of centralized processing and can be used further by a consumer in two ways: either directly, or serve as output data for series of prod-ucts resulted from processing using mathematical, statistical and geographic information systems. In order to process obtained data the UHMI developed a modular system that allows unification of the means of primary and secondary processing of output data and enabling all necessary channels for transmission of generated data using a wide range of protocols. To visualize the lightning data a subsystem based on the open GeoServer for preprocessing of the geodata and client tools using the mapping data of OpenStreetMap are used. As an example of one of possibilities these lightning data provide, the analysis of the spatial and temporal distribution of lightning activity over the ter-ritory of Ukraine from June 10 to September 30, 2016 has been done and the results showed that these data could be a new, qualitative source of data for climatological studies. In addition, real-time data acquisition allows creation of a series of products for a wide range of consumers inter-ested in a short-term forecasting.

Keywords

• lightning finding, the ENTLN system, data processing, lightning discharges