Lightning activity in Belgium during 2001–2011

In this study we present cloud-to-ground (CG) and cloud-to-cloud (CC) lightning activity over the period 2001-2011 in Belgium. Particular attention is given to the geographical incidence of both CG strokes and flashes; of interest for lightning protection purposes. Depending on the adopted settings to validate and locate CG discharges, a mean stroke and flash density over this 11-year period (/km²/yr) in Belgium is found ranging from 0.74-1.8 and 0.48-0.99, respectively. The CC/CG flash ratio experiences a yearly variation with an average value of 1.94. Most of the lightning activity takes place during the summer months with a peak in the afternoon. In addition, for the year 2011, CG detections are correlated with outage reports of high-voltage transmission lines provided by the Belgian transmission system operator ELIA. Looking at outage reports having an allocated lightning cause, we detect in 74% of the cases lightning activity that could be the reason of the outage.