Assessment of the impact of WRF microphysical schemes on precipitation forecasting during spring in the Democratic People's Republic of Korea

Abstract

In this study, the WRF model was used to evaluate the impact of microphysics schemes on the prediction of rainfall during spring in the Democratic People's Republic of Korea (DPRK). The rainfall event was divided into two categories according to the daily accumulative rainfall amount and rainfall distribution: rainfall events with small precipitation(<10 mm/d) and partial coverage of the precipitation area (hereafter SPRE) and rainfall event with relatively large precipitation(≥10 mm/d) and entirely covered area (hereafter LERE), and numerical simulations were carried out for six typical rainfall events (three days for each category) in 2021–2022. The simulation results confirmed that the effects of microphysics schemes differ from each other according to the precipitation event. In the analysis of the simulation results, the accuracy was evaluated using the critical success index (CSI) and false alarm ratio (FAR) indices for SPRE, and MODE analysis was used to assess the agreement with centers of rainfall patterns for LERE. For SPRE, the one-moment bulk microphysics scheme is rather efficient than the more sophisticated two-moment bulk microphysics scheme, and the Ferrier scheme performs best. For LERE, the two-moment bulk microphysics scheme performs better than the one-moment microphysics scheme. In particular, the Thompson and Thompson aerosol-aware schemes have a higher performance than the other schemes. The results of this study suggest that seasonal effective physical process schemes should be selected for operational forecasting, and will help to improve the accuracy of the forecast for spring in the DPRK.