Radar-based assessment of hail frequency in Europe

Abstract

Abstract. In this study we present a unique 10 year climatology of severe convective storm tracks for a large European area covering Germany, France, Belgium and Luxembourg. For the period 2005–2014, a high-resolution hail potential composite of 1×1 km2 is produced from two-dimensional radar reflectivity and lightning data. Individual hailstorm tracks as well as their physical properties, such as radar reflectivity along the tracks, were reconstructed for the entire time period using the Convective Cell Tracking Algorithm (CCTA2D). A sea-to-continent gradient in the number of hail days per year is found to be present over the whole domain. In addition, the highest number of severe storms is found on the leeward side of low mountain ranges such as the Massif Central in France and the Swabian Jura in southwest Germany. A latitude shift in the hail peak month is observed between the northern part of Germany, where hail occurs most frequently in August, and southern France, where the maximum amount of hail is 2 months earlier. The longest footprints with high reflectivity values occurred on 9 June 2014 and on 28 July 2013 with lengths reaching up to 500 km. Both events were associated with hailstones measuring up to 10 cm diameter, which caused damage in excess of EUR 2 billion.

Evaluation of convective parameters derived from pressure level and native ERA5 data and different resolution WRF climate simulations over Central Europe

“…It is therefore essential to assess the spatiotemporal distribution of convective phenomena during historical and future climate periods, which can be accomplished using observations, reanalysis products, and numerical model output (Brooks 2013;Tippett et al 2015;Brooks et al 2019). A straightforward climatological analysis of convective weather events is difficult due to dataset limitations regarding human reports (Groenemeijer and Kühne 2014;Czernecki et al 2016), remote sensing techniques (Punge et al 2014(Punge et al , 2017Taszarek et al 2019;Fluck et al 2021), and the relatively coarse resolution of model simulations with parameterized convection (Weisman et al 1997;Prein et al 2015). As an alternative, proxy parameters have been used to identify environmental conditions favorable for the occurrence of deep convection (e.g., Rasmussen and Blanchard 1998;Brooks et al 2003;Púčik et al 2015;Taszarek et al 2020a).…”

Swabian MOSES 2021: An interdisciplinary field campaign for investigating convective storms and their event chains

“…Based on analyses of radar, lightning, and insurance loss data, several studies (Kunz and Puskeiler, 2010;Puskeiler et al, 2016;Enno et al, 2020;Fluck et al, 2021) found evidence that (severe) thunderstorms in southwestern Germany preferably form east of the Black Forest ridge and around or over the Swabian Jura. (Kunz and Puskeiler, 2010) hypothesized that low-level flow convergence as a consequence of a predominant flow-around regime around the Black Forest is paramount to the increased frequency of convective storms in this area.…”

“…Eight stations of the Parsivel disdrometer network, which are most frequently affected by hail according to long-term radar data analyses (Puskeiler et al, 2016;Fluck et al, 2021), were additionally equipped with the automatic hail monitoring system HailSens from Hyquest Solutions. Hailstones hitting a sensing area of approximately 0.2 m 2 generate a vibration of a plate, which is recorded by a piezoelectric microphone mounted beneath the plate.…”

Characteristics of hail hazard in South Africa based on satellite detection of convective storms

“…In addition, reanalyses or regional climate models use simplified microphysical parameterization schemes and not two-or even three-moment schemes required for more realistic hail size modeling (Seifert and Beheng, 2006;Loftus et al, 2014;Wellmann et al, 2020). Several studies have used hail signals or hail detection algorithms for hail frequency assessments (Cintineo et al, 2012;Junghänel et al, 2016;Fluck et al, 2021) and risk modeling (Puskeiler et al, 2016;Nisi et al, 2018;Schmidberger, 2018). However, radar data are usually only available on country scales due to availability and inter-radar calibration issues.…”