Investigating the Impact of Radar Observation Height on Streamflow Modeling: The 31 May 2013 El Reno/Oklahoma City, Oklahoma, Flash Flood Case

Weather radar is an instrumental tool during the flash flood warning process due to its ability to fill in spatial gaps between in situ rain gauges. However, radar has inherent errors in its rainfall estimates for multiple reasons, including a variety of drop size distributions, polarimetric bias, and elevation of the beam relative to the precipitation. This study seeks to examine the effect of radar beam height on streamflow modeling through the degradation of high-resolution radar data in height, leading to a better understanding of radar network density effects on flash flood warning accuracy. KOUN WSR-88D I/Q data from the 31 May 2013 El Reno/Oklahoma City, OK flash flood case are degraded in azimuthal resolution with each tilt and re-processed to create Level-II moments and Level-III products that simulate a farther range to the radar. Radar observations simulated for these different ranges are input to the Ensemble Framework for Flash Flood Forecasting (EF5) hydrologic model to simulate streamflow for this event. The resulting predictions are compared to observed streamflow measurements.