Abstract
To investigate the characteristics of regions exhibiting multiple lightning initiations within a finite volume and a short time, the lightning location data obtained from the convective regions of 14 mesoscale convective systems were analyzed in combination with data from radar. In total, 415 out of 5996 radar grids (1 km × 1 km × 0.5 km) were found to initiate more than one flash within 6 min. Only 49 grids showed an initiation density of more than two flashes within 6 min. The grids with high flash initiation densities were found to have a similar distribution to those with one lightning initiation within 6 min, in terms of altitude and reflectivity relative to altitude. They also showed similar trends in their frequency evolution. The grids with higher initiation densities seemed to be more concentrated in the altitude range of 9–13 km. However, only one was found to form at a lower altitude near the melting level when lightning initiation clearly declined. Moreover, the spatial relationship of this lower higher-initiation density grid to the reflectivity core was different to that in the main altitude range. In this paper, the possible dynamic and electrical mechanisms of the formation of this lower higher-initiation density grid are discussed.
Highlights
The conditions of regions displaying lightning initiation represent an important research topic for the improvement of lightning warning systems and the assessment of lightning risk, as well as for gaining insight into the conditions allowing lightning initiation and propagation
Based on the data from the radar and the lightning location system, 6333 grids at which lightning flashes were initiated were found in all 14 MCSs
As mentioned in Wang et al [17], because of the limitation of the observation domain, some MCSs with a larger area than the observation domain and some MCSs partly within the observation domain could be partially captured by the observation domain for both radar echo and lightning flashes
Summary
The conditions of regions displaying lightning initiation represent an important research topic for the improvement of lightning warning systems and the assessment of lightning risk, as well as for gaining insight into the conditions allowing lightning initiation and propagation. It is common practice to carry out such research using lightning location data combined with weather radar data. Based on this method, many previous studies have obtained a range of research results relating to the reflectivity in the lightning initiation regions and their altitude distributions [1–6]. Many previous studies have obtained a range of research results relating to the reflectivity in the lightning initiation regions and their altitude distributions [1–6] The findings of these studies indicate that lightning flashes are usually initiated in regions with a moderate reflectivity range of. The peak distribution areas of lightning initiation relative to altitude and reflectivity have a relatively low altitude range and a relatively small reflectivity range for mesoscale convective systems (MCSs) (8–9 km and 30–35 dBZ), those with multiple cells (8–10 km and 30–35 dBZ), and those with supercells
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