Is the number of days with lightning changing? A study for southeastern Europe of the period 1980–2018

Abstract

Lightning is one of the leading causes of weather-related fatalities worldwide and also has a strong impact on atmospheric chemistry (i.e., NOx production). Lightning can also lead to power system breakdowns, ignite forest fires, damage wind turbine and lead to perturbation of transportation, in particular to aviation. Thus, knowing when, where lightning strike and which atmospheric environments are more frequently associated with lightning is important. Furthermore, given the increase in the population density in recent decades (i.e., more people are exposed to lightning) and the increased urbanization (i.e., cities are getting larger and thus are more exposed to lightning) is essential to understand the spatial and temporal distribution of storm producing lightning and their environments in the current climate and their changes in the past and coming decades. To address these issues, in this study we analyze the changes in the number of days with atmospheric conditions leading to lightning over southeastern Europe. Here we consider the non-inductive charging mechanism as the main mechanism for cloud electrification. We search for ingredients supporting for this cloud electrification mechanism using a series of parameters (e.g., convective available potential energy, total precipitable water, heights of various isotherms) obtained from vertical profiles collected from radiosonde sites over southeastern Europe (e.g., Romania, Hungary, Bulgaria). This paper will present the changes between 1980 and 2018 in the number of days with condition supporting the occurrence of lightning in urban areas from southeastern Europe.