Statistical characteristics, circulation patterns, and environmental features of severe convective wind events in Beijing

Abstract

A climatological study of 206 severe convective wind (SCW) events from April to September during 2016–2023 in Beijing was conducted. Results show events primarily occur in summer, with a peak in the afternoon and a much weaker secondary peak in the early morning. They are relatively more frequent in mountainous areas than in plains，with the southern foothills of Yanshan Mountain being the most affected area.

Circulation patterns associated with SCW events, ranked by frequency, include the low-pressure vortex-subtropical high, deep trough, low-level jet, subtropical high periphery, transverse trough, dual low-pressure vortex, and easterly flow patterns. Convective organization modes, also ranked by frequency, consist of cluster cells, broken line, nonlinear-shaped systems, hybrid systems, squall line, individual cell, and bow echo. SCW events are mainly triggered by convective systems coming from the northwest and west. In environments with high precipitable water, such as the low-level jet and subtropical high periphery patterns, nonlinear-shaped and hybrid systems are more prevalent. In contrast, in very dry environments, such as the deep trough pattern, broken lines and cluster cells occur more frequently. Strongly organized convective systems, such as squall lines and bow echoes, often exist in circulations with a westerly low-pressure vortex. Generally, a drier atmospheric environment tends to produce stronger winds, while moist conditions increase the frequency of SCW events. These findings highlight the influence of circulation patterns and environmental conditions in SCW events.