An evaluation of WRF microphysics schemes using the satellite-observed vertical structure of heavy rainfall over the Korean peninsula

Recently, it was found that heavy rain system over the Korean peninsula is more associated with low-level clouds (i.e., warm-type heavy rainfall), in contrast to the traditional view that deep convection with abundant ice water content produces heavy rainfall. This finding leads to a conjecture that microphysics schemes have been developed in state-of-the-art models to simulate the severe weather such as in the United States; however, such schemes may not work well over Korea owing to the different cloud–rain system. Therefore, the performance of microphysics parameterization for simulating heavy rainfall over the Korean peninsula should be comprehensively evaluated. This study aims to evaluate the eight microphysics schemes in the Weather Research and Forecasting (WRF) model using the satellite-observed vertical structure of heavy rainfall over the Korean peninsula. The evaluation result exhibited that Double Moment 6-class (WDM6) scheme simulates the most realistic vertical structure of heavy rainfall among eight WRF microphysics schemes by virtue of the smallest amount of snow and modified warm-rain physics (e.g., size distribution and accretion process). However, excessive graupel in the WDM6 scheme was thought to be a problem. In conclusion, improvement of microphysical parameterization based on observations is thought to be an important factor for enhancing the predictability of warm-type heavy rainfall over the Korean peninsula.