A 10-Year Study on the Characteristics of Thunderstorms in Belgium Based on Cloud-to-Ground Lightning Data

Abstract

emporal and spatial distributions of cloud-to-ground (CG) lightning in Belgium are analyzed. Based on data from the European Cooperation for Lightning Detection (EUCLID) network, spanning a period of 10 years between 2004 and 2013, mean CG flash densities vary between 0.3 km?2 yr?1 in the west up to 2.4 km?2 yr?1 toward the east of Belgium, with an average flash density of 0.7 km?2 yr?1. The same behavior is found in terms of thunderstorm days and hours, where in the east most of the activity is observed, with a drop-off toward the coast. The majority of lightning activity takes place in the summer months between May and August, accounting for nearly 90% of the total activity. Furthermore, the thunderstorm season reaches its highest activity in July in terms of CG detections, while the diurnal cycle peaks between 1500 and 1600 UTC. A correlation is found between the estimated peak currents and altitude, with on average higher absolute peak currents at lower elevations and vice versa. In addition, a cell tracking algorithm is applied to the data to monitor the behavior of the individual cells. It is found that the lightning cells travel at an average speed of about 25 km h?1, with a preferred northeasterly direction of movement. At last, CG flash rates are strongly related to the cell area.