Bottom-dominated negative dipole charge structure in thunderstorms over Tibetan Plateau

The Tibetan Plateau stands as the highest plateau globally, showcasing distinct geological and climatic characteristics. Thunderstorms there usually shows unique structural and spatiotemporal features compared to those in low-altitude plains, and they typically exhibited small size, short duration, lower charging and flash rate. Using the data from the accurate lightning VHF interferometer, electric field mill, fast/slow antenna and C-band radar, evolution of charge structure of thunderstorms involved in lightning discharge are investigated. Different from the lower-altitude thunderstorm usually starting from a positive dipole charge structure in the middle upper portion of cloud, the charge structure inside thunderstorm usually evolves from an initial inverted dipole charge structure. In the mature stage, it may keep the inverted dipole in the whole life cycle of the thunderstorm, or exhibit a bottom heavy tripole charge structure with a large lower positive charge center (LPCC). Under different magnitudes of the LPCC, various lightning discharges including -IC, +IC, -CG and bolt-from-blue flashes are generated, indicating the crucial effects of LPCC on the lightning discharge types.