- 1Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China (dsongag@connect.ust.hk)
- 2Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China (ceim@ust.hk)
- 3Division of Environmental Science and Engineering, POSTECH, Pohang, Republic of Korea
While the added value of Convection-Permitting Models (CPMs) in precipitation simulations compared to regional climate models with typical horizontal resolutions has been gradually recognized across various regions, systematic investigations of CPMs' ability to capture the major characteristics of extreme precipitation in South Korea remain limited. To address this gap, this study aims to develop a Weather Research and Forecasting (WRF)-based Convection-Permitting Model (CPM) with a 3 km horizontal resolution and to optimize its performance in reproducing historical extreme events by adjusting the domain size and turning spectral nudging on/off. For this purpose, we selected three record-breaking extreme rainfall cases in South Korea caused by quasi-stationary fronts. Using the peak date as the center, simulations are conducted for a total of 15 days, including a 7-day spin-up period both before and after the peak. We design three domains with expanding sizes, all centered over the Korean Peninsula with a uniform horizontal resolution of 3 km. Their differences in the lateral boundary conditions allow us to perform sensitivity tests to determine the optimal domain size and lateral boundaries for accurately reproducing heavy precipitation events. Their lateral boundary conditions derived from ECMWF-ERA5 reanalysis data at 6-hour intervals. In addition, we assess the effectiveness of spectral nudging by comparing the model performance with and without spectral nudging. A coefficient of 0.0003 s-1 is applied to winds above the planetary boundary layer, showing improvements in reproducing time-series, synoptic patterns, and vertical structures against observations. If the optimal configuration of the CPM contributes to reproducing extreme precipitation events over the Korean Peninsula, it will be helpful for understanding their physical mechanisms.
Acknowledgments
This study was supported by the Korea Meteorological Administration Research and Development Program under Grant RS-2024-00403386, Republic of Korea.
How to cite: Song, D., Im, E.-S., Kwon, D., Seo, G.-Y., and Min, S.-K.: Impacts of Spectral Nudging and Domain Size on Heavy Precipitation Simulations in Korea using a Convection-Permitting Model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7868, https://doi.org/10.5194/egusphere-egu25-7868, 2025.
