Intercomparisons of Radial Velocity Measurements from Initial All-Digital Horus PAR Observations with Fixed-Site Weather Radars

Rapid-scan observations of radial velocity signatures can have great utility in an operational weather surveillance, especially during severe weather events. For example, the Phased Array Radar Innovative Sensing Experiment (PARISE) studies conducted using the National Weather Radar Testbed (NWRT) PAR data generally found increased lead-time and confidence in issuing tornado warnings. A fully digital PAR network could further enable the study and operational detection of tornadoes through not only vertically dense, rapid-scan volumetric capabilities, but also leveraging PAR-enabled adaptive strategies (e.g., digital beamforming). While a limited number of PAR datasets of supercells and tornadoes exist, until recently, no platform with an all-digital beamformer existed to evaluate different PAR architectures available for a future operational PAR network for weather surveillance. With support from the NOAA National Severe Storms Laboratory (NSSL), the University of Oklahoma’s Advanced Radar Research Center has developed Horus—the first fully digital, polarimetric, S-band mobile PAR. This mobile radar platform will serve as an additional proof of concept of a future operational PAR network with its digital beamforming capabilities.

In this study, observations of convective storms collected by Horus are analyzed. Horus is capable of collecting volumetric updates on the order of 1 min or less while leveraging the flexibility of PAR in collecting densely sampled vertical scans. This allows more in-depth analysis of features - like mesocyclones – placing an emphasis on the vertical and temporal resolution not offered by other radar systems. Horus observations were taken during the spring 2023 convective season in Oklahoma with plans to continue these efforts in the next few months, and these data will provide the initial results for analysis of radial velocity observations (and signatures when possible). Intercomparisons will be done with KTLX, PX-1k, RaXPol, and other nearby radars to evaluate Horus’s data quality. As one means of comparing the datasets, we will match the cross-beam resolution of Horus and nearby radars. These initial observations and results from Horus serve as motivation to further assess the benefits and utility of fully digital, polarimetric PAR observations of supercells and tornadoes as well as develop future scanning strategies tailored to high-impact weather events.