Research Tools: Phased Array Radar

The Phased Array Radar (PAR) project was established to demonstrate the potential to simultaneously perform aircraft tracking, wind profiling, and weather surveillance with a single phased array weather radar. NOAA's National Weather Radar Testbed (NWRT) was a repurposed U.S. Navy SPY-1A phased array radar built in the 1970’s, tested and evaluated in Norman, Oklahoma.

Electronic Steering

Current weather radars mechanically rotate and tilt the radar dish to sample different parts of the atmosphere. A phased array radar has a unique flat panel antenna that remains stationary. The panel is made up of a grid of fixed antenna elements, and each can transmit and receive a signal. As a result, the radar beam can be steered electronically, giving users the ability to control how, when and where the radar scans. This means the radar can be controlled to direct its beam only where storms are detected. Focused observations of storms lead to faster updates since the radar does not waste time scanning clear-air regions.

Rapid Scanning

PAR can scan the sky in less than a minute, revealing critical weather thumbprints that point to the potential of severe weather. Radar scans every minute will make severe weather easier to confirm, making warnings more accurate and reducing false alarms. Forecasters will also be able to watch changes in the storm to know when it is strengthening or weakening. NSSL scientists have already learned more about thunderstorms with PAR data.

An independent study estimates implementation of a combined PAR network of radars satisfying both FAA and NWS missions will save the taxpayer $4.8B over the life-cycle of the radar.

PAR Research

PAR researchers at NSSL are endeavoring to:

  • Develop and implement signal processing techniques to improve the quality, coverage, and accuracy of meteorological products from weather radars,
  • Develop and demonstrate adaptive scanning and rapid update capabilities for weather observations leading to increased severe weather warning lead times,
  • Demonstrate dynamic scheduling of multi-function scanning strategies,
  • Develop a radar controller interface,
  • Develop severe weather detection algorithms and displays to utilize the unique data provided by the PAR,
  • Evaluate rapid-scanning NWRT PAR data to provide insights into the development of severe weather and the potential to increase lead times of tornado warnings. (Phased Array Radar Innovative Sensing Experiment),
  • Develop specs for a dual-polarized PAR and evaluate various design issues,
  • Test and evaluate any dual-pol PAR prototypes,
  • Develop and implement signal processing techniques to improve the quality, coverage, and accuracy of meteorological products from weather radars,
  • Develop and demonstrate adaptive scanning and rapid update capabilities for weather observations leading to increased severe weather warning lead times,
  • Demonstrate dynamic scheduling of multi-function scanning strategies, and
  • Develop a radar controller interface.

Benefits of PAR

Enhanced weather surveillance

  • Adaptive sensing will lead to continued improvements to the severe weather warning system for tracking tornadoes, strong wind gusts, hail and locally heavy rains responsible for flash floods and mudslides.
  • More precise hazardous weather information affecting flight safety and airspace capacity will provide economic efficiency to domestic aviation and surface transportation systems.
  • Better weather data will be used to initialize runs of numerical prediction models.
  • More detailed atmospheric observations will improve air quality nowcasts and forecasts, climate variability monitoring and forecasting, and wildfire monitoring and prediction.
  • The ability to see fine-scale wind fields will lead to better atmospheric transport and diffusion modeling of chemical/biological/radiological hazard tracks.

Enhanced aircraft surveillance

  • Homeland security will benefit from PAR's non-cooperative aircraft tracking capability in U.S. airspace.
  • Commercial aviation will benefit from aircraft tracking capability.

Significant long-term cost savings

  • An PAR network using affordable phased array technology will provide unprecedented weather observing and forecasting, critical surveillance support for homeland defense, save lives and protect property, and provide economic benefit to the Nation.

History of Phased Array Radar

Navy ships originally used AEGIS phased array radar (called SPY-1) technology to protect naval battle groups from missile threats. Researchers believe the same technology has great potential for increasing lead-time for tornado warnings.

In 2000, the U.S. Navy agreed to loan a phased array antenna to NSSL and provided the $10,000,000 in funding to help build the National Weather Radar Testbed (NWRT). The NWRT is a facility focused on developing faster and more accurate warning, analysis and forecast techniques for severe and hazardous weather using phased array and also upgraded WSR-88D radar technology. The National Weather Service provided the transmitter and the additional funding from NOAA, OU, Lockheed Martin, and Oklahoma State Regents for Higher Education purchased the environmental processor. In addition, the FAA provided initial funding for research, program management and initial upgrades, and the NWS has donated equipment. The NWRT became operational in September 2003, and the first data were collected in May, 2004.

Collaborators and Partners

The National Weather Radar Testbed is a unique partnership among academia, industry, federal and state government agencies, and the Navy with a common goal of transforming military technology into a civilian research facility that will provide great benefit to the nation.