Three-Dimensional Lightning Characteristics Analysis over the Tibetan Plateau Based on Satellite-Based and Ground-Based Multi-Source Data

Abstract

Based on the data from the Chinese national ground-based (LFEDA: Low-frequency E-field Detection Array) and satellite-based lightning-detection systems (LMI: Lightning Mapping Imager), the spatial and temporal distribution statistical properties of all types of lightning over the Tibetan Plateau in the summer of 2022 and 2023 are analyzed, and were compared with those in Hainan, which are under quite different geographical conditions. The discrepancy between ground-based and space-borne lightning detection was also discussed. The main results show the following: (1) the characteristics of lightning activities over the Tibetan Plateau based on multi-source data: Most of the high-value lightning areas were located in the transition zone between lower and higher terrain; the diurnal variation of lightning activity was significant, and the most active period concentrated around 15:00 LST (Local Standard Time, the same below). In addition, lightning activities were significantly increased at 21:00 and 0:00, which was related to the unique topography and night rain phenomenon of the plateau. In terms of lightning types, the number of IC (Intra-Cloud) lightning was more than that of CG (Cloud-to-Ground). The study of IC changes is of great significance to the early warning of the plateau DCSs. The spatial distribution of IC at different altitudes was quite different. (2) Comparison of lightning activities between the Tibetan Plateau and Hainan: The hourly variation of lightning activities in Nagqu showed a single peak, while that in Hainan was characterized by a primary peak and a secondary peak, affected by the enhancement of the boundary stream in the low latitude and altitude area of China. At the peak of convection, the lightning activities in Nagqu were less than 1/3 of that in Hainan. However, the duration of high-frequency lightning activities in Nagqu (15–19:00) was about 2 h longer than that in Hainan (15–17:00), which may be related to the fact that the Tibetan Plateau is located in the west of China, where the sunset is later, and solar radiation and convective activities last longer. (3) Analysis of features of LMI: LMI has more advantages in IC detection; LMI has higher detection efficiency for the lightning in the range of 4–6 KM altitude, which is partly related to the stronger convective process and the higher proportion of IC. This work will provide deeper understanding of the characteristics of all types of lightning over the Tibetan Plateau, to reveal the indication significance of lightning for DCSs, and help to promote the development of Chinese satellite-based lightning-detection technology, the optimization of subsequent instruments and the fusion application of ground-based and satellite-based lightning data.