Characteristics and Risk Assessment of Winter Mid-level Precipitation Events in Central Korean Peninsula

겨울철 한반도 중부지역 중층 강수 현상의 특성과 위험성 연구

This study investigates the meteorological characteristics of mid-level precipitation during winter in the central Korean Peninsula, focusing on both their formation mechanisms and potential hazardous outcomes. Using ERA5 reanalysis and KMA observational data from 2000 to 2023, we first identified 18 reference events of mid-level precipitation provided by KMA for the period 2017~2023. Based on these reference events, we established objective criteria for mid-level precipitation and subsequently selected 100 additional cases from 2000~2023 that met these criteria. The analysis revealed distinct synoptic-scale pressure patterns, characterized by a westward-tilting system with mid-upper level (700-500 hPa) troughs west of the Korean Peninsula and surface lows developing in the initial stage. The vertical structure showed a clear contrast between dry lower layers (below 700 hPa) and moist mid-upper layers, with strong ascending motion observed between 700-300 hPa. Surface precipitation was recorded in only 36% of cases, with an average of 1.3 mm. Pattern correlation analysis between composite and individual cases showed high similarities (> 0.9) at 700-500 hPa levels, confirming the consistency of synoptic patterns. With mean 925 hPa temperature at -0.4℃, freezing rain potential was particularly high near mountainous regions, including Mt. Jiri and Sobaek Mountains. This first systematic analysis of mid-level precipitation characteristics contributes to improving winter weather forecasting accuracy and establishing effective disaster prevention systems, particularly for transportation infrastructure vulnerable to freezing rain conditions.