Simulation of polarimetric radar variables from the CAPS Spring Experiment Storm Scale Ensemble Forecasts

An existing polarimetric radar data simulator is modified and applied to results from the CAPS Storm Scale Ensemble Forecasts (SSEF) as part of the yearly Hazardous Weather Testbed Experimental Forecast Program Spring Experiment. The simulated variables are calculated based on the forecast model output variables and include reflectivity at horizontal polarization (Zh) , differential reflectivity (Zdr), and specific differential phase (Kdp). Modifications are required to accommodate the different microphysics (MP) schemes used by the forecast members including Milbrandt and Yau, WDM6, Thompson, and Morrison. The schemes differ based on both the number of included hydrometeor categories and number of predicted moments. The enhanced simulator is tested with results from the 2013 Spring Experiment. Results show generally reasonable simulated values but highlight significant differences in the cloud microphysics between the results of different forecast members. The simulated variables provide insight on the representation of hydrometeor particle size distributions (PSDs) by each of the MP schemes and are used as a tool to evaluate the performance of the schemes. Results are compared to observations from the WSR-88D network which was recently updated to include dual-pol variables.