Demonstrating the Value of PAR at NSSL: A Faster, More Flexible, and Adaptable Solution

The National Severe Storms Laboratory (NSSL) National Weather Radar Testbed (NWRT) operates a 1.5° beamwidth, S-band, dual-polarized phased array radar (PAR) named the Advanced Technology Demonstrator (ATD). The ATD is being used to demonstrate the utility of PAR technology as a potential replacement option for the next operational radar network backbone. PARs can scan electronically and provide much more flexibility than a mechanically rotating dish radar (e.g., WSR-88D). This allows PAR to achieve faster volume update rates of around 60 – 90 seconds with as low as a 30 – 45 second low level revisit, as opposed to the 5 – 7 minute volumetric update and minimum 90 second low level revisit of the current operational network. This faster update rate affords the opportunity to incorporate additional scans (e.g., range height indicators) in scanning strategies and the ability to collect additional moments using single-polarization transmission modes (e.g., Linear Depolarization Ratio).

Further speed and flexibility increases can be realized using spoiled transmit beams, a technique implemented on the ATD in 2024, whereby a wider volume is illuminated and the direction of echoes is determined by digital beamforming. Additionally, adaptive scanning techniques are being developed to focus on the most impactful storms by further increasing update rates to observe important meteorological phenomena. Meteorological datasets collected with the ATD over the last several years are being utilized across the PAR program at NSSL, spanning the entire research-to-operations paradigm including engineering techniques, kinematic and microphysical studies, Hazardous Weather Testbed activities, and informing the National Weather Service. This presentation will share our recent successes and lessons learned from PAR research and development (R&D) efforts at NSSL. Discussion of our results from HWT experiments, the impacts volumetric update rates may have on the future operational paradigm (including algorithms and impact-based decision support), and several new concepts of operations the ATD will utilize for R&D in 2025 and beyond will occur.