The Role of Physical Forcing on the Development of Mesoscale Convective Systems along the West Coast of South Korea during KPOP-MS Field Campaign

Convective initiation processes during the warm season are particularly sensitive to near-surface boundaries and terrain features, posing a significant challenge for improving quantitative precipitation forecasts during this period. Gyeonggi Bay, located on the west coast of South Korea near the densely populated Seoul Metropolitan area, is approximately 60 kilometers from the city center. The bay spans over 500 kilometers and features numerous smaller bays, capes, and a diverse array of islands. Therefore, a comprehensive understanding of the coastal effects on the life cycle of mesoscale convective systems (MCSs) is essential for improving warm-season precipitation forecasting in the Seoul Metropolitan area. To address this need, a major field experiment called the Korea Precipitation Observation Program: International Collaborative Experiments for Mesoscale Convective Systems in the Seoul Metropolitan Area (KPOP-MS) was initiated in 2023.

During the first year of the field campaign, we identified a convective initiation event on the west coast on August 7, 2023. Both X-band and S-band polarimetric radars captured the convective initiation and the stagnation of convective cells along the coastline, likely due to continuous convective initiation near the coastal region. This suggests that near-surface boundaries, such as sea breeze fronts, in conjunction with the complex topography and coastal features, play a critical role in triggering convective cells. To gain a deeper understanding of the dynamical processes involved in the evolution of the MCSs and the potential effects of cloud microphysical processes over this region, we utilized the Wind Synthesis System using Doppler Measurements (WISSDOM), which includes data from four X-band and one S-band radar, as well as Storm Tracker data—ultra-lightweight, multi-channel, simultaneous radiosonde measurements—launched every three hours during the event at six different locations in the coastal area. These various remotely sensed and in-situ data, with relatively high spatiotemporal resolution, clarified the coastal effects on the development of MCSs in the coastal region near the Seoul Metropolitan area.

This work was funded by the Korea Meteorological Administration Research and Development Program under Grant RS-2023-00237740.