Comparative Analysis of Flash and Radar Characteristics of Thunderstorm Cells

Abstract

In the evening of 20 August 2006 a severe thunderstorm hit Budapest causing 4 people’s death and leaving seven hundred people injured who were on the streets on the occasion of the traditional Constitution Day’s fireworks which attract thousands of people every year. This entailed deep and detailed analysis of the weather conditions and the development of this thunderstorm, as well as of the operation of observational now casting systems of the Hungarian Meteorological Service (HMS). The investigation of radar and flash characteristics was made by interactive and automatic cell segmentation and tracking methods developed at HMS for comparative analysis. Both methods provide the following attributes for every radar cells with different dBZ thresholds: centre and maximum dBZ values and their coordinates, area, radar rainfall intensity, water production and total water. The centre, the maximum values of flash density and their coordinates, area, flash activity and total flash count for every flash cell with different flash density thresholds are also calculated. In the course of the comparative analysis the radar and flash characteristics of the thunderstorms of the 3 August 2006 were also computed. On this day the highest flash activity was observed in Hungary since the SAFIR type lightning location network is in operation. The authors are underlying the importance of using such methods in the operational practice of HMS.