Assessment of Lightning Activity and Early Warning Capability Using Near-Real-Time Monitoring Data in Hanoi, Vietnam

This study investigates lightning activity and evaluates a near-real-time lightning warning system for the inner Hanoi area, using data collected during 2020–2024 from the Strike Guard (SG) and EFM-100C instruments located in Chuong My, Hanoi, Vietnam. Lightning detection data were incorporated with rainfall and lightning location information from the Vietnam Meteorological and Hydrological Administration (VNMHA) for quality checking. The SG data over the research area revealed clear diurnal and seasonal variations, with lightning most frequent in the late afternoon and two major peaks in June and September corresponding to the summer monsoon. A combined warning method using EFM-100C electric field measurements and SG alert states achieved an average lead time of 15 min, a Probability of Detection (POD) of 82.22%, a Critical Success Index (CSI) of 76.55%, an F1 score of 86.72%, and a False Alarm Ratio (FAR) of 8.26%. These results demonstrate that integrating electric field and optical–electromagnetic measurements can provide effective localized lightning warnings for the urban areas. The approach is cost-efficient, operationally feasible, and particularly valuable for protecting critical infrastructure regions, supporting enhanced lightning safety and disaster mitigation in northern Vietnam.