Evaluate Radar Data Assimilation in Two Momentum Control Variables and the Effect on the Forecast of Southwest China Vortex Precipitation

Based on the Weather Research and Forecasting (WRF) Model three-dimensional variational (3DVAR) data assimilation system, this study investigates effects of radar reflectivity radial velocity under different momentum control variables forecast Southwest China Vortex precipitation. It is shown that U−V variable strengthens wind speed vorticity to be better matching observation, while using ψ−χ as will produce too large increments which are unphysical. The root mean square errors (RMSE) around 2.4 m/s in experiment variables, RMSE below 2 with variables. composite from analysis matches observation than i.e., rain band location more accurate. enhances cold high-pressure system near surface, not significant. water vapor flux convergence lower layers overestimated leading excessive precipitation forecast. Equitable Threat Score (ETS) about 0.1 higher variable. In summary, superior terms forecasting