Abstract:
Based on lightning location data and hourly and minute-level precipitation data from automatic weather stations in Sichuan Province from 2018 to 2023, the lead time of lightning activity characteristics in extreme short-term heavy precipitation was analyzed. The results show that: (1) Positive cloud-to-ground (PCG) lightning dominated in leading precipitation peaks, with the leading proportions of its average intensity peak and frequency peak being 49.4% and 43.0%, respectively. The average lead time of the intensity peak was the longest (16.7 minutes). The leading proportions of negative cloud-to-ground (NCG) lightning frequency and intensity peaks were also significant, at 36.0% and 33.3%, respectively. (2) The lead times of both PCG and NCG lightning frequencies were mainly concentrated within 10—20 minutes, while the intensity peak of PCG lightning generally led precipitation peaks by 10—30 minutes, with a maximum lead time of 50 minutes. The intensity was strongest at a 30-minute lead time, and the corresponding precipitation peak decreased as the lead time increased. The average intensity of NCG lightning is generally lower than that of PCG lightning, but its maximum peak intensity within 10—20 minutes was close to that of PCG lightning. (3) In the western Sichuan Basin, the lead times of both PCG and NCG lightning frequencies generally exceed 10 minutes, while the lead time of PCG lightning in the northeastern part was relatively short. The intensity peak of PCG lightning led precipitation peaks by more than 10 minutes in most areas of the basin, with some regions reaching 40—50 minutes. The lead time of NCG lightning intensity was more concentrated in the northern part of the basin, reaching 20—30 minutes.