Evaluation of WRF Parameterizations in Simulating Seasonal Precipitation Over Japan

Abstract

Japan) 3 Member of JSCE, Dr. Eng., Senior Researcher, International Centre for Water Hazard Risk Management (Tsukubashi, Ibaraki-ken 305-8516, Japan)The impact of parameterization scheme usage to precipitation was investigated in WRF model for simulating 24-km seasonal precipitation over Japan. Budget profile analysis was used to diagnose unresolved heating/drying processes controlled primarily by cumulus (CU) parameterizations, and how coupling of CU scheme with boundary layer (BL), microphysics (MP) and radiation (RAD) schemes modulate the unresolved processes that consequently impacts simulated precipitation. Results showed hothumid JJA precipitation is sensitive to CU scheme as shown by the large variation in PCC and SDR scores of different schemes validated against APHRODITE data. And, distinct structure of heating/drying profiles were seen from each CU scheme. The CU scheme coupling with BL scheme showed larger modulation on heating/drying profiles and larger PCC-SDR variation as compared to coupling with MP-RAD schemes. This provides a systematic evaluation of scheme usage and its combinations in simulating precipitation.