Influence of PBL-CPS Combinations and Resolution on the Simulation of East Asian Summer Monsoon Precipitation in 2022 Using WRF

The East Asian Summer Monsoon (EASM) presents a formidable challenge for regional climate modeling due to its intricate interactions between atmospheric dynamics, oceanic variability, and regional processes. This study explored how different Planetary Boundary Layer (PBL) and Cumulus Parameterization Schemes (CPS), alongside horizontal resolution, influence the simulation of EASM precipitation in 2022. Using the Weather Research and Forecasting (WRF) model, simulations were conducted over the CORDEX-East Asia domain at 12 km resolution with a nested 4 km domain, incorporating four distinct PBL-CPS combinations.

Comparisons with satellite and ground-based observations reveal that Multi-scale Kain-Fritsch (MSKF)-based schemes consistently outperform KIM Simplified Arakawa-Schubert (KSAS)-based schemes, offering more reliable representations of monsoon precipitation. High-resolution simulations more effectively capture localized terrain effects and convective processes. However, specific combinations, such as the Asymmetric Convective Model version 2 (ACM2)-KSAS, tend to overestimate convection in lower latitudes. Conversely, MSKF-based schemes exhibit reduced sensitivity to resolution changes and provide a more accurate representation of monsoon frontal progression. This highlights the critical role of parameterization choices in modulating large-scale monsoon dynamics and local-scale variability.

These findings offer valuable insights into the interactions between parameterizations, resolution, and large-scale monsoon processes, contributing to the enhancement of regional climate model performance. Moreover, this study emphasizes the importance of carefully optimized modeling strategies to improve EASM precipitation forecasts, particularly in the context of climate change and its influence on extreme events.