Spatiotemporal changes of lightning incidence and its relationship with dynamic and thermodynamic factors over a lightning prone tropical region
摘要
The study addresses the elevated occurrence of lightning activity and associated incidents over Kerala, India, where the topography is complex. It aims to systematically investigate the spatiotemporal variations in lightning activity while elucidating the intricate relationships of lightning occurrences with dynamic and thermodynamic variables. Lightning distribution over India indicates relatively prominent lightning activity in Kerala. Analysis of climatological data reveals that the peak of lightning activity in Kerala is observed in April, in the pre-monsoon season, with an average of 0.2 ∓ 0.05 flashes km-2 day-1. Notably, the Kottayam district and its nearby areas exhibited high lightning frequencies of ≥ 0.3 flashes km-2 day-1 during this period. A secondary peak in lightning activity was recorded in October from the post-monsoon season, though comparatively less intense than during the pre-monsoon season (0.05 ∓ 0.008 flashes km-2 day-1). However, the regions west of the Palakkad Gap (PG) experience less lightning incidence. Further, the spatial analysis of dynamic and thermodynamic parameters (Convective Available Potential Energy (CAPE), K-Index, and pressure vertical velocity at 500 hPa) proved a clear and causative association with lightning occurrences in Kerala. The study also analyses the moisture transport to explore its migration during periods of heightened lightning activity. The trends observed in CAPE exhibit a significant correlation with lightning activity, especially during the pre-monsoon season.