A Study on the Trends of Wildfire Potential in South Korea over the Past 60 Years

This study investigated the temporal trend of wildfire potential in South Korea over the past 60 years (1965-2024) by analyzing surface-layer atmospheric variables, particularly relative humidity (RH) and its derived effective humidity, collected from the Korea Meteorological Administration (KMA)’s Automated Synoptic Observing System stations. The spatial distribution and temporal trend of the annual mean RH were examined, along with their statistical correlations with temperature and vapor pressure. The analysis revealed a pronounced decline in the annual mean RH, which was generally accompanied by an increasing trend in temperature. In contrast, the vapor pressure trend exhibited substantial spatial variability, suggesting the influence of localized factors. Lastly, the return periods of the KMA’s warning level dryness events, defined as periods when effective humidity is ≤25% for two or more consecutive days estimated from the 60 years dataset indicate relatively short return levels in eastern coastal regions, such as Gangnueung, Pohang, and Ulsan, and southeastern cities, such as Busan and Daegu. Notably, the frequency of these warning-level dryness events, which can be interpreted as indicators of wildfire potential, has increased significantly over the past 30 years. The effective-humidity-based analysis of dry warnings in this study enables the quantitative evaluation of temporal trends in wildfire occurrence potential and can serve as foundational data for climate change adaptation and wildfire management policy development. In future research, we plan to strengthen the accuracy and predictive performance of drought-risk assessments by applying the Simple Ranking Method and extreme-value theory (Peaks Over Threshold and Block Maxima) to consecutive dry-warning events (effective humidity ≤25%) and comparing the return periods derived from each method.