Leader of early Doppler radar development passes away

An original founder of the National Severe Storms Laboratory and an instrumental leader of early Doppler radar development recently passed away. Kenneth “Ken” Wilk helped establish NOAA’s National Severe Storms Laboratory and its reputation as the leading federal laboratory focused on weather radar. 

He received his Bachelor of Science in physics and chemistry from the University of Illinois and a Bachelor of Science in meteorology from Penn State University. He served in the U.S. Air Force as a weather forecaster supporting fighter-bomber squadrons and then worked for the Illinois Water Survey in Champaign, Illinois, on thunderstorm research.

Wilk led the Weather Radar Laboratory in Norman from its inception in 1962, a component of the National Severe Storms Project, prior to the establishment of the NSSL. He was the manager of the NSSL’s Operations Groups in the 1960s, directing numerous projects to improve radar and radar displays. The Operations Group’s mission was to improve storm warnings with the then-operational, non-Doppler radars at the U.S. Weather Bureau Forecast Offices. The Operations Group was a forerunner of today’s Radar Operations Center in Norman, Oklahoma, which oversees NEXRAD Doppler radar maintenance and installations around the world.

Ken Wilk and Dave Zittel discussing Doppler weather radar equipment with two Congressional leaders
Former NSSL researchers, Ken Wilk (third from the left) and Dave Zittel (at the far right) present information to Congressional leaders and other influential members of the science community during a visit to NSSL to evaluate and recommend continued and more substantial support for Doppler weather radar research.

In 1977, he was involved with the Joint Doppler Operational Project (JDOP) to prove Doppler radar could improve the nation’s ability to warn for severe thunderstorms and tornadoes. This project and its researchers outlined specifications of a new generation of weather radar for national network use. As a result of the project, the NWS, U.S. Air Force’s Weather Service, and the Federal Aviation Administration decided to include Doppler capability in their future operational radar network, called NEXRAD.

The NSSL determined Doppler weather radar could detect not only thunderstorms but also dangerous gust-fronts, wind shear, and in-storm turbulence. The NEXRAD network was installed nationwide in the early 1990s and is still in use today.

Wilk’s research and management of the Interim Operational Test Facility in Norman was instrumental in ensuring the successful development of NEXRAD Doppler radars and the first operational deployments of the new radars, beginning in 1991.

Wilk was always thinking of new ideas. He excelled at writing proposals, test plans and final reports documenting results of NSSL’s tests to satisfy grant requirements, and collaborated on many technical reports.

Wilk retired in 1988 after many years of Federal service. His keen interest in thunderstorms and methods of their detection was a motivation to others throughout his later years.  

Wilk’s family will celebrate his life at a private mountainside ceremony.

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Collaboration improves UK and US radar techniques to improve forecasts

The national weather radar system used throughout the United States by NOAA National Weather Service  forecasters to “see” weather across the country is unique because it can be upgraded and modified with the newest capabilities, unlike other systems worldwide.

Because of this, and the need to work with experts in radar signal processing for improving the quality of radar data, international partners from the United Kingdom Met Office are collaborating with researchers from The University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies at the NOAA National Severe Storms Laboratory to develop new techniques for U.K.-based radars.

The U.K. Met Office operated a radar system that did not allow changes and was considered a “commercial off-the-shelf solution.”

“Most weather services in the world purchase radar systems from companies and in those systems, the signal processor is typically a black box,” said Sebastian Torres, senior research scientist with OU CIMMS and NSSL. “The signal processor is a key component in all weather radar systems. Its job is to convert echoes received by the radar into weather images. It’s something most weather services don’t really have access to. They know how it works but they can’t change or improve anything.”

The U.K. Met Office decided to build its own signal processor for their radar systems. This allows a similar degree of flexibility to that of the NEXRAD radars, also known as the WSR-88D (weather surveillance radar-88 Doppler), operated in the United States. NOAA offered some of its tested techniques to the U.K. Met Office and in return received access to valuable data it could use for future research and operations.

Inside every NEXRAD radar is a rotating parabolic antenna. As the antenna rotates, it travels up and around while sending out pulses of electromagnetic energy. When radars send and receive these pulses, buildings and other structures may obstruct the radar’s view, contaminating the storm data.

To help keep unwanted objects from impacting storm data, Torres and fellow CIMMS Researcher David Warde developed two complementary signal-processing techniques for the WSR-88D. One technique, called CLEAN-AP, or Clutter Environment Analysis using Adaptive Processing filter, removes unwanted radar echoes from objects on the ground. The other one, called WET or Weather Environment Thresholding, intelligently decides when the CLEAN-AP filter should be applied. This prevents slow-moving storms from being confused with stationary objects.

NSSL and CIMMS researchers Sebastian Torres and David Warde (second and third person from the left) visited the UK Met Office in Exeter from February 22-26, 2016 to support implementation of CLEAN-AP on the UK weather radar network.

 

“The goal of CLEAN-AP and WET is to clean the data as much as possible so the forecasters have the best data available to make warnings and forecasts,” Torres said.

Through collaboration with the U.K. Met Office, who implemented CLEAN-AP and WET, the techniques were fine-tuned and improved. Both techniques are being transferred to the NOAA National Weather Service, and CLEAN-AP is licensed by OU to U.S. weather radar manufacturer Baron.

CLEAN-AP before and after

 

Another CIMMS Researcher, Igor Ivic, developed a third product transferred to the U.K. called the Radial-by-Radial Noise Estimator. RBRN  improves the quality of radar data by removing “noise,” the radar equivalent of radio static or television static. It was implemented on the U.S. NEXRAD network as part of ongoing research-to-operations efforts at NSSL and CIMMS.

“If you have noise and you can remove it from the radar returns, then you get just the signal, and that can be used to get better quality data,” Torres said.

Torres called the collaboration a “win-win” situation because the information exchange, as well as the new technologies and techniques that have been developed are good for both the U.S. and U.K.

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