Characteristics of the evolution of the severe rainfall cells structure in the Leading Line Meso-scale Convective System and the lightning activity

The data from the Doppler radar, SAFIR3000 lightning location system and high-density automatic meteorological stations observations are used to design a variety of radar quantitative parameters and analyze the evolution of cells structures, the lightning activity and electrical vertical structure of the severe rainfall cells structure in a Leading Line Meso-scale Convective System (LL-MCS). The relationship between convective cells and β-mesoscale LL-MCS is revealed. The conclusions are as follows. At first, the four cells (Gu'an in Hebei, Shunyi and Fangshan in Beijing, Baodi in Tianjin) in the single squall respectively brought rainfalls of about 23 mm, 50 mm, 27 mm and 70 mm in one hour. In the Fangshan cell, two smaller monomers were merged. The cell of Shunyi was followed by the other cell. In the Gu'an and Baodi cell, their development is related to LL-MCS by feeding and swallowing. Secondly, V40 (40 dBz echo volume range), V40UP-6 (40 dBz echo volume above the height of 6 km), SET11 (echo area range at 11 km level) could describe the 3D quantitative structure change of a cell, and Fcg (CG lightning frequency) and Fic (IC flash frequency) were closely related to the radar parameters, such as its correlation coefficient with V40UP-6 being between 0.63 and 0.97. The flash frequency of IC was more sensitive than CG to echo structure change. Thirdly, the height of the radiant point maximum concentration area in the Gu'an cell was below 6 km, which was far lower than the other cells at the same stage. At last, the feature of lightning frequency of CG and lightning frequency of IC increased with the main positive charge area significantly lifted after the merger of convective cells, and the characteristics of the lightning frequency increase showing relationship with the rainfall intensity increasing as well as the lightning frequency peak leading the maximum of rainfall intensity have positive significance for warning of disaster weather.