Spatiotemporals analysis of cloud-to-ground lightning activity in Sri Lanka from 2020 to 2024 using ground-based detection data

Abstract

Lightning is a major weather-related hazard in Sri Lanka, posing frequent risks to human life, infrastructure, and socio-economic activities. The objective of this research is to advance the understanding of lightning climatology in Sri Lanka, with the aim of strengthening early-warning services and improving risk management for lightning-related hazards. This study analyses the spatiotemporal distribution of cloud-to-ground lightning activity across Sri Lanka during 2020–2024, using data from the Earth Networks Global Lightning Network (ENGLN). The analysis examines seasonal, monthly, and diurnal variations, as well as lightning density and district-level patterns. Results reveal a pronounced bimodal seasonal distribution, with peak activity occurring during the first (March–April) and second (October–November) inter-monsoon periods. A strong diurnal cycle is evident, with most lightning strikes concentrated in the late afternoon, between 14:00 and 18:00 local time, reflecting the influence of surface heating on convective development. Spatial analysis identifies persistent lightning hotspots, primarily in the western coastal districts of Colombo, Gampaha, and Kalutara, as well as in the central highlands. While the coastal hotspots are linked to mesoscale circulations, moisture convergence, and urban heat island effects, lightning activity in the highlands is enhanced by orographic lifting. District-level assessments highlight temporal variations in peak lightning months and dominant hours, supporting targeted early warning and risk communication strategies. By identifying patterns and trends in lightning activity, the results are expected to provide valuable inputs to operational meteorological services, disaster management agencies, and policymakers. Additionally, the findings have implications for public education and community-based risk reduction in lightning-prone areas.