Analysis of the lightning production of convective cells

Abstract. This paper presents an analysis of the lightning production of convective cells. The cells were detected by the MeteoSwiss Thunderstorms Radar Tracking (TRT) algorithm in the course of a lightning measurement campaign that took place in the summer of 2017 in the area surrounding the Santis mountain, in the northeastern part of Switzerland. For this campaign, and for the first time in the Alps, a Lightning Mapping Array (LMA) was deployed. In the first part of the paper, we examine the relationship between the intra-cloud (IC) and cloud-to-ground (CG) activity and the cell severity as derived by the TRT algorithm of a large dataset of cells gathered during the campaign. We also propose and analyze the performance of a new metric to quantify lightning intensity, the rimed particles column (RPC) height and base altitude. In the second part, we focus on two of the most severe cells detected during the campaign that produced significantly different outcomes in terms of the lightning activity. The paper shows that the newly proposed metric (RPC) seems to be a very promising predictor of lightning activity, particularly for IC flashes. Future lightning nowcasting algorithms in any case should be probabilistic in nature and incorporate the polarimetric properties of the convective cells as well as the lightning climatology.