Sensitivity Tests of Assimilating Thermodynamic Variables with Radar Observations in the Ensemble Kalman Filter System

With observing system simulation experiments (OSSEs), this study evaluates the impacts of assimilating different thermodynamic variables with radar observations. By using the WRF-LETKF Radar Assimilation System (WLRAS), state variables of temperature, pressure and water vapor in 3D are assimilated to the system. Through the sensitivity tests, the performance of the analysis and short-term forecast are evaluated. The goal is to identify what kind of measurement other than radar can efficiently improve the quantitative precipitation forecast at convective scale.