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

Abstract

Abstract. Accurate estimates of hail risk to exposed assets, such as crops, infrastructure, and vehicles, are required for both insurance pricing and preventive measures. Here we present an event catalog to describe the hail hazard in South Africa guided by 14 years of geostationary satellite observations of convective storms. Overshooting cloud tops have been detected, grouped, and tracked to describe the spatiotemporal extent of potential hail events. It is found that hail events concentrate mainly in the southeast of the country, along the Highveld, and around the eastern slopes. Events are most frequent from mid-November through February and peak in the afternoon, between 13:00 and 17:00 UTC. Multivariate stochastic modeling of event properties yields an event catalog spanning 25 000 years, aiming to estimate, in combination with vulnerability and exposure data, hail risk for return periods of 200 years.

Characterizing hail-prone environments using convection-permitting reanalysis and overshooting top detections over south-central Europe

“…Only OTs detected with the Khlopenkov et al (2021) algorithm having a probability >50% are considered, similar to Punge et al (2023). This statistical constraint was derived by the comparison of OT detections with radar echo tops (Cooney et al, 2021) that demonstrated enhanced reliability being indicative of colder and more prominent anvil-relative tops.…”

“…However, some OTs with intense updrafts reaching the tropopause and penetrating the lower stratosphere may be associated with convective environments not necessarily supportive of severe weather phenomena such as hail. The necessary discrimination between hail-and non-hail-producing OTs can be attained by additionally considering convection-related environmental conditions estimated with reanalysis (Punge et al, 2017;Bedka et al, 2018;Punge et al, 2023).…”

A study on the DAM-EfficientNet hail rapid identification algorithm based on FY-4A_AGRI

“…By utilizing NDVI and ground surface temperature data and applying threshold and anomaly detection methods, they successfully distinguished hail damage across different growth seasons, providing solid support for precise hail impact monitoring in the agricultural sector. Moreover, Heinz Jürgen Punge and his team 7 , through a 14-year satellite study, identified the key distribution zones and high-incidence periods for hail in South Africa, offering important data for long-term hail risk assessments. W.J.W.…”

A Climatology of Dryline‐Related Convection on the Western Plateau of Subtropical Southern Africa

“…This region, locally known as the Highveld, exceeds heights of 1,500 m above sea level and has been identified as a potentially severe convective environment (Blamey et al., 2016). The Highveld is one of the regions with the highest hail day frequency in southern Africa (Dyson et al., 2020; Punge et al., 2023). Average annual rainfall decreases drastically toward the western interior, which also experiences dry spells regularly (Thoithi et al., 2021).…”