Statistics of Cloud-to-Ground Lightning Activity over North China during 2009–2023

Abstract

This study analyzes the spatiotemporal distribution and peak current (PC) characteristics of cloud-to-ground lightning (CG) over North China (NC) from 2009 to 2023, based on observations from the Advanced Directional Thunderstorm Detector (ADTD) network. The results show that 4,294,310 CG flashes are detected over the 15-year period; approximately 87 % are negative CG flashes (NCG). Approximately 48 % of multi-stroke NCG contain at least one subsequent stroke with a PC exceeding that of the first stroke. The spatial distribution of CG in NC is influenced by local topography, with two density maxima located in the western mountains and the northeastern mountainous fringe. Positive CG flashes (PCG) generally concentrate along mountain–plain transition zones with steep terrain gradients in western and northern NC. CG activity exhibits pronounced interannual variability: NCG frequency decreases significantly from 2013 to 2020, which leads to a marked increase in the proportion of PCG (P_PCG). This interannual change may be largely attributed to the implementation of regional air pollution control measures that reduce aerosol concentrations; such reductions may alter cloud microphysics and thereby contribute to the observed CG trends. Monthly CG variability is strongly tied to monsoon activity: CG frequency peaks in the warm season, whereas P_PCG is higher in the cold season. More than half of thunderstorm days (TSD) in NC occur in summer. Thunderstorms typically initiate over mountains in the afternoon and propagate eastward onto the NC Plain.