A Climatology of Thunderstorms across Europe from a Synthesis of Multiple Data Sources

Abstract

The climatology of (severe) thunderstorm days is investigated on a pan-European scale for the period of 1979–2017. For this purpose, sounding measurements, surface observations, lightning data from ZEUS (a European-wide lightning detection system) and European Cooperation for Lightning Detection (EUCLID), ERA-Interim, and severe weather reports are compared and their respective strengths and weaknesses are discussed. The research focuses on the annual cycles in thunderstorm activity and their spatial variability. According to all datasets thunderstorms are the most frequent in the central Mediterranean, the Alps, the Balkan Peninsula, and the Carpathians. Proxies for severe thunderstorm environments show similar patterns, but severe weather reports instead have their highest frequency over central Europe. Annual peak thunderstorm activity is in July and August over northern, eastern, and central Europe, contrasting with peaks in May and June over western and southeastern Europe. The Mediterranean, driven by the warm waters, has predominant activity in the fall (western part) and winter (eastern part) while the nearby Iberian Peninsula and eastern Turkey have peaks in April and May. Trend analysis of the mean annual number of days with thunderstorms since 1979 indicates an increase over the Alps and central, southeastern, and eastern Europe with a decrease over the southwest. Multiannual changes refer also to changes in the pattern of the annual cycle. Comparison of different data sources revealed that although lightning data provide the most objective sampling of thunderstorm activity, short operating periods and areas devoid of sensors limit their utility. In contrast, reanalysis complements these disadvantages to provide a longer climatology, but is prone to errors related to modeling thunderstorm occurrence and the numerical simulation itself.

Investigation of the temporal variability of thunderstorms in central and western Europe and the relation to large‐scale flow and teleconnection patterns

“…Overall, a positive gradient in WMILX frequency is identified both in north‐to‐west and west‐to‐east directions, that is, along the coastlines of the North Atlantic and the Baltic Sea. This general distribution of convective environments is confirmed by similar studies based on reanalysis (Mohr et al ., ; Prein and Holland, ; Rädler et al ., ; Taszarek et al ., ), lightning (PK17; Taszarek et al ., ), and satellite (Punge et al ., ) data. However, there are major differences in the area of the Alps and their surroundings, mainly because orographically induced circulations and resulting convergence zones, which are mainly relevant for the triggering of convection, are not sufficiently resolved by the coastDat‐2 reanalysis.…”

“…Across the domain, convection‐favouring conditions primarily occur ahead of upper‐level troughs, consistent with similar studies (Kapsch et al ., ; Merino et al ., ; Punge and Kunz, ; Westermayer et al ., ; Mohr et al ., ; Taszarek et al ., ). In some regions, however, further flow configurations were shown to provide favourable pre‐convective environments such as, for example, a broad upper‐level low over the Adriatic Sea favouring thunderstorm occurrence in southern Poland.…”

Relationship between atmospheric blocking and warm‐season thunderstorms over western and central Europe

“…; Piper and Kunz, ; Taszarek et al . ). Because the study area covers western and central Europe, our analyses focus on the four warmest months with the highest thunderstorm activity: May, June, July and August (Anderson and Klugmann, ; Poelman et al .…”

“…; Piper and Kunz, ; Taszarek et al . ). Small differences from other TD probability maps result mainly from varying threshold definitions of a TD, consideration of other time periods (especially the considered months) and/or the spatial resolution (detection area) of the TD map.…”

Application of a simple analytical model to severe winds produced by a bow echo like storm in northeast Italy

“…A high frequency of storms has been reported, particularly during the warm season, including frequent occurrence of severe events like tornadoes, hailstorms and lightning (Giaiotti et al, 2007;Pucillo et al, 2009;Manzato, 2012;Feudale and Manzato, 2014). In general the area is one of the most affected by heavy rain and thunderstorms over the whole of Europe (Isotta et al, 2014;Poelman et al, 2016;Pavan et al, 2019;Taszarek et al, 2019a). In particular, severe events have been observed and studied in the region of the Friuli Venezia Giulia (FVG) plain (Figure 1) over the last 20 years (Bechini et al, 2001;Giaiotti et al, 2001;Bertato et al, 2003;Manzato et al, 2015).…”