Assessment of Coastal Effects on the Intensity and Structure of Mesoscale Convective Systems in the Korean Peninsula

The majority of Mesoscale Convective Systems (MCSs) that impact the Korean Peninsula originating over the shallow and warm Yellow Sea have been observed to advance inland during warm season. The proximity to the peninsula's western coastline introduces intricate dynamics owing to land-sea contrasts, coastal complexities, and varied topography. Notably, Gyeonggi Bay, extending over 500 kilometers, encompasses numerous smaller bays, capes, and an array of islands. Given its adjacency to the densely populated Seoul Metropolitan area housing approximately 25 million residents, comprehending the interaction between MCSs and the coastal features holds pivotal significance for precise precipitation forecasting, crucial for disaster mitigation strategies.

In the context of our investigation, we examine a MCS occurrence on August 2, 2020. While a squall line exhibited sustained linear convective band over the ocean during its eastward propagation, a notable shift to a bow-shaped convection line was observed upon approaching Gyeonggi Bay. Our analysis indicates a correlation between this MCS type alteration and the amplification of the rear inflow jet along with the emergence of vertical vortices. To attain this results, the Wind Synthesis System using Doppler Measurements (WISSDOM) was employed, leveraging data from an array of 11 Doppler radars strategically deployed around the Seoul Metropolitan area, incorporating S-band, C-band, and X-band systems.

Furthermore, our inquiry extends to clarifying the predominant driver behind the coastal influence on bow echo development near the coastline. To achieve this, sensitivity tests were executed utilizing WRF-ARW model simulations. This multi-faceted investigation sheds light on the intricate relationship between dynamics of MCSs and coastal impacts, contributing to enhanced forecasting accuracy and disaster preparedness.