Evaluation of bulk microphysics parameterizations for simulating the vertical structure of heavy rainfall between Korea and the United States

Abstract

The Korean Peninsula and the United States (US) have many contrasting precipitation characteristics that are part of the oceanic monsoon and continental convection. This study evaluated 11 microphysics schemes in the Weather Research and Forecasting model in terms of vertical reflectivity structure for heavy rainfall during the summer in Korea and the US. Compared to satellite radar observation, the correlation coefficients for the reflectivity structure for 11 microphysics schemes were 0.581–0.906 and 0.745–0.918 for the Korean and US domains, respectively. We observed that a simple scheme (such as the use of single moment and limited ice categories) does not always fail, and complex methods do not always succeed. The relatively low correlation over Korea versus the US was assumed because many microphysics parameterizations were developed and tuned over the US. Consequently, some microphysics schemes exhibited a severe overestimation of reflectivity in both the upper and lower levels over the Korean Peninsula. In contrast, a microphysics scheme that was evaluated and improved for both continental and maritime convection regions, showed the best performance on the Korean Peninsula too. This highlights the importance of evaluation for various regions with different precipitation characteristics to improve parameterization of cloud microphysics. Because Korean and US domains are representative areas of oceanic monsoon and continental convection, we expect that this study can serve as a conceptual guide to suggest which microphysics parameterizations should be used for a realistic simulation in continental and oceanic monsoon precipitation regimes.

Keywords

• GPM
• WRF
• Microphysics
• Heavy rainfall
• Korea
• United States