38CVC Classified Pattern and Trend Analyses of Summer Heavy Rainfall in Korea

The monsoon season on the Korean Peninsula (KP) typically results in concentrated heavy rainfall, which often leads to substantial human and property losses. In August 2022, the monsoon front became stationary in the central region of the KP, where the hourly maximum rainfall surpassed the capacity of Seoul's drainage infrastructure. A 24-hour maximum rainfall of 435mm was recorded, leading to severe flooding. To improve early predictions of future monsoon events, especially in distinguishing between cases that occur in different regions, this study aims to classify the synoptic weather patterns associated with monsoons on the KP. Principal Components Analysis (PCA) and K-means clustering were applied to classify the synoptic weather patterns of monsoons occurring between 2000 and 2022. The ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) was employed to identify the most critical variables in differentiating various types of heavy rainfall events during the monsoon season on the KP. We examine whether this approach can effectively distinguish between heavy rainfall in different regions—the central, southern, and northern regions of the KP. Furthermore, this study identifies the most influential variables that differentiate the types of heavy rainfall events, including atmospheric pressure, temperature, humidity, and wind. Classifying the synoptic patterns of heavy rainfall systems during the monsoon season on the Korean Peninsula is essential for forecasting future weather events, particularly in identifying regional differences. This research could provide a foundation for predicting future heavy rainfall during the monsoon season in specific regions of the KP.