Association of lightning occurrence with precipitation cloud column structure at a fixed position

Abstract

In this study, a C-band frequency-modulated continuous-wave (C-FMCW) radar, with its feature of vertical detection, was combined with lightning discharge recordings within a 3 km range to investigate the dependence of lightning occurrence on the structure of precipitation cloud columns (PCCs) from the perspective of a fixed position. The results show that, relative to PCCs without lightning, PCCs with lightning exhibit greater maximum reflectivity, maximum upward radial velocity, maximum velocity spectrum width, cloud top height, and vertically integrated liquid in terms of their average values, and wider-range distributions of these parameters. Using the Light Gradient Boosting Machine algorithm, a lightning diagnosis program that integrates multiple C-FMCW radar parameters was developed. Its hit rate of lightning occurrence is 93.5% and it has a threat score of 0.421. The maximum velocity spectrum width above the melting layer was found to be the most effective in distinguishing PCCs with or without lightning. It was suggested that the hydrometeor properties at a specific location, specifically the size diversity and content of ice-phase particles, should be the key elements determining the occurrence of lightning in PCCs.