Phased Array Radar: National Weather Radar Testbed at NSSL

NSSL and its partners celebrated the end of construction and the beginning of installation and checkout of the phased array radar with a ribbon-cutting ceremony on April 25. Doug Forsyth, chief of NSSL's Radar Research and Development Division and executive director of facilities and strategic planning, said, "It started as a dream in 1997...now it's finally coming together." The phased array radar project will begin a new era in NSSL's leadership in the research and development of future generations of weather radar. All aspects of the phased array project are being carried out in a unique federal, private, state and academic partnership that includes NOAA NSSL and NWS, Lockheed Martin (LM), U.S. Navy, Federal Aviation Administration (FAA), Basic Commerce and Industries, Inc., the Oklahoma State Regents for Higher Education (OSRHE), and the University of Oklahoma's (OU) School of Meteorology and College of Engineering. The testbed will enable meteorologists and engineers to determine if phased array radar will become the next significant technology advancement to improve our nation's weather services.

The phased array radar technology was originally used by Navy ships to protect naval battle groups from missile threats. Scientists believe the same technology has great potential for increasing lead time for tornado warnings. In 2000, the Navy agreed to loan an antenna to NSSL and provided $10M in funding to help build the National Weather Radar Testbed (NWRT). The NWS provided the transmitter and additional funding from NOAA, OU, LM, and OSRHE 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 phased array radar has a unique antenna that allows it to collect the same amount of information as the conventional radar, but in about one-sixth the time. The current average lead time for NWS tornado warnings is 10 to 11 minutes. Researchers believe phased array could expand lead times to 18-22 minutes. Scientists will be able to adapt the radar scan to focus on the most important weather features. The new technology will also gather storm information not currently available, such as rapid changes in wind fields, to provide more thorough understanding of storm evolution. Researchers and forecasters can then improve conceptual storm models and use that knowledge to evaluate and improve stormscale computer models.

The project--from research and development to technology transfer and deployment throughout the U.S.-- is expected to take 10 to 15 years. The radar's infrastructure is under construction and is scheduled to be completed by the end of this summer. Research is expected to begin in August.

Above: The rapid scanning ability of phased array radar has the potential to significantly increase the average lead time of tornado warnings. Right: An illustration of the various components of a phased array radar.