Real-time, High-resolution QPE System for CASA DFW Urban Radar Network

Urban flash flood is one of the most commonly encountered hazardous weather phenomena. Rapid urbanization has made the densely populated areas even more vulnerable to flood risks. Hence, accurate and timely monitoring of rainfall at high spatiotemporal resolution is critical to severe weather warning and civil defense, especially in urban areas. Radar has been used for rainfall estimation since the beginning of its weather application.

Since 2012, the U.S. National Science Foundation Engineering Research Center (NSF-ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) has initiated the development of Dallas-Fort Worth (DFW) radar remote sensing network for urban weather hazards mitigation. The DFW urban radar network consists of a combination of high-resolution X-band radars and a standard NEXRAD radar (i.e., KFWS radar). High-resolution quantitative precipitation estimation (QPE) is one of the major research goals of the deployment of CASA DFW urban radar network.

In this paper, the real-time, high-resolution QPE system developed for this urban radar network will be presented. The QPE system is designed via fusion of observations from both the high-resolution X-band radar network and the S-band KFWS NEXRAD radar. The specific dual-polarization rainfall algorithms at different frequencies (i.e. S- and X-band) will be described. In addition, the fusion methodology combining observations at different resolution will be described. Cross-comparisons between ground rain gauge measurements and radar rainfall products demonstrate the excellent performance of this urban QPE system. The high-resolution QPE products are being used for urban flash flood forecasting when coupled with hydrological models.