Radar improvement helps forecasters to “see” storms better

Radars are a vital tool for weather forecasters because they provide a detailed picture of storms as they’re happening. A new radar technique is improving the picture for forecasters, helping them provide more accurate information about rain and snow storms.

An example of the RBRN technique.

Developed by researchers at University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies and NOAA’s National Severe Storms Laboratory, the improvement is now being shared with collaborators an ocean away. The United States-based engineers collaborated with meteorologists at the United Kingdom Met Office on the technique called Radial-by-Radial Noise estimator, or RBRN, to improve radar signal returns in storms.

“Through this unique collaboration paradigm, we’ve proven that scientific partnerships can transcend geographical, political and proprietary boundaries,” said Sebastian Torres, CIMMS researcher leading NSSL’s Advanced Radar Techniques Team. “The atmosphere knows no geographical boundaries. Better forecasts in the UK can provide improved information to the United States, and vice versa, as we continue to build partnerships to help save lives, property and minimize the economic impact of severe weather in the U.S.”

Weather radars often pick up noise from various sources like the sun or man-made devices similarly to how a radio or television sometimes retrieve a static signal. The RBRN analyzes radar beam data in real-time and performs several tests to ensure the noise can be detected and measured.

“Accurate measurement of noise on weather radars is critical as it impacts the accuracy of radar data and plays a key role in data quality control,” Torres said.

In addition, a portion of energy from the radar beam may also be absorbed by particles in its path before the radar beam energy is returned.

“This weakens the echoes from locations far from the radar and gives the wrong impression that storms in these locations are weaker than they truly are,” Torres said. “Because the particles in the radar beam path emit noise, the noise measured by RBRN can be used to correct for the weakening or attenuation of echoes as the radar beam intersects storms. The operational RBRN estimator significantly improves the quality of radar data, especially for weak returns associated with snow storms and gust fronts.”

Reducing and accurately measuring contamination from the noise in the radar data equates to better information and more accurate forecasts for the public.

The RBRN was originally developed by CIMMS Researcher Igor Ivic and became operational in the U.S. NEXRAD radar network in 2014.

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Collaboration with Taiwanese agency foundational to NSSL’s MRMS system

Recently a delegation from the Taiwan Central Weather Bureau and Soil and Water Conservation Bureau  visited NSSL for a project review. The visitors include the director of the CWB Meteorological Satellite Center, the director of the SWCB Debris Flow Disaster Prevention Center, one research meteorologist from CWB and two engineers from SWCB. NSSL scientists provided briefings on the latest Multi-Radar Multi-Sensor research and development efforts, and the visitors discussed their operational needs and challenges related to hydrological predictions in a tropical region with complex terrain.

Collaboration is a fundamental aspect of research at NOAA National Severe Storms Laboratory and recently a group from Taiwan’s Central Weather Bureau and Soil and Water Conservation Bureau visited the lab in Norman, Oklahoma.

The partnership between NSSL and CWB began 16 years ago when both agencies worked to develop and implement an early Multi-Radar Multi-Sensor System version and integrate it into CWB’s radars.

The collaboration grew with the joint interest in developing advanced quantitative precipitation estimate applications to address heavy precipitation over complex terrain associated with typhoons and hurricanes,” said Kenneth Howard, research scientist with NSSL. “The CWB collaboration was foundational to NSSL’s research and development of MRMS system operationally deployed in the United States.”

Such collaborations are important because the atmosphere does not stop at geographical borders.

“These partnerships and opportunities expand our knowledge of advancements in weather and hydrological research and operations around the world,” said Jian Zhang, research meteorologist. “Further, the collaborations leverage resources and expertise in different agencies for a more effective research and development effort to address challenges for different geographical and climatological regions.”

The recent visit provided an opportunity for each agency to present an update on projects and to review progress. The mid-term review allows the CWB project managers to meet with the various participating NOAA agencies in the U.S. This year SWCB joined the review and visited NSSL and the Global Systems Division of NOAA’s Earth Systems Research Laboratory in Colorado.

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International collaboration benefits US, European forecasters

NOAA National Severe Storms Laboratory Researcher Adam Clark at the European Severe Storms Laboratory Testbed this summer.

Weather doesn’t stop at borders. Nowhere is this more clear than in Europe, where two researchers working at the NOAA National Severe Storms Laboratory went shoulder to shoulder with researchers in the European Severe Storms Laboratory Testbed this summer. The goal was to collaborate on forecast products and learn how NSSL technologies are used abroad.

“As scientists and meteorologists, we need to continue to talk because that’s how true knowledge transfer occurs,” said Darrel Kingfield, University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies researcher working at NSSL. “ESSL researchers came to work with us in the NOAA Hazardous Weather Testbed a couple of years ago and this year we went to them.”

Darrel Kingfield presenting at the European Severe Storms Laboratory Testbed this summer.

During its sixth year, the ESSL Testbed program evaluated forecasts for high-impact weather. Like the HWT, the ESSL testbed serves as a forum to stimulate interaction between product developers and operational forecasters from throughout Europe. Also, lectures from several local and international experts help testbed participants enhance their knowledge and skills.

Different geography, systems

Kingfield and NSSL Research Scientist Adam Clark each spent a full week at ESSL’s testbed. What struck them was the difference in geography between the United States and Europe. Clark said ingredients needed for severe weather come together much differently in Europe than the U.S.

“You have the Mediterranean Sea and the Alps and that affects much of their weather,” Clark said.

Adam Clark working in the European Severe Storms Laboratory Testbed.

Along with geographical differences, Clark and Kingfield learned about the different weather prediction and monitoring systems operated by each European country. A variety of forecasting tools and methods are used throughout Europe, from government operated to privatized systems. This results in data, forecasting and verification inconsistencies.

“For example, after a tornado occurs in the U.S., officials observe and record where it occurred and how severe it was,” Kingfield explained. “Europeans rarely go out and assess tornado damage after a storm. Those surveys are reserved for most damaging events.”

As a result, Europe’s tornado database is not nearly as complete as the United States.

Sharing tools and techniques
While in the testbed, Kingfield and Clark gazed upon a few familiar products.

“The German Weather Service is using a lot of the same techniques developed at NSSL to interpret radar data,” Kingfield said. Some European meteorologists use several products developed in the U.S. by NSSL and OU CIMMS researchers. For instance, one technique allows them to use radar data to visualize the possible track of a tornado based on the storm’s rotation.

Collaboration is an important tool for forecasters and researchers. Participation in ESSL’s testbed allows researchers like Kingfield and Clark to share new technologies, experience new techniques and learn new systems. Opportunities like this allow researchers to collaborate on new products and technology, ultimately leading to better forecasts and warnings for the American public.

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Significant Publication: Collaborative Efforts between the United States and United Kingdom to Advance Prediction of High-Impact Weather

The following significant paper publication was reported to headquarters the week of May 19. NOAA authors are bolded.

  1. Collaborative Efforts between the United States and United Kingdom to Advance Prediction of High-Impact Weather”

By John S. Kain (NSSL) , Steve Willington, Adam J. Clark (NSSL), Steven J. Weiss (NWS SPC), Mark Weeks, Israel L. Jirak (NWS SPC), Michael C. Coniglio (NSSL), Nigel M. Roberts, Christopher D. Karstens (OU CIMMS/NSSL), Jonathan M. Wilkinson, Kent H. Knopfmeier (OU CIMMS/NSSL), Humphrey W. Lean, Laura Ellam, Kirsty Hanley, Rachel North, Dan Suri.

Published in May 2017 American Meteorological Society’s Bulletin of American Meteorological Society, pages 937-948.

Significance: The Met Office brought expertise gained from its efforts using convection-allowing models (CAMs) to better represent the convective storms that bring flash flooding in the United Kingdom. The infusion of Met Office models and perspectives dovetailed exceptionally well with the rapidly growing National Severe Storms Laboratory and Storm Prediction Center proficiency in using CAMs to help predict tornadoes, large hail, and damaging winds. The successful collaborative efforts of the Hazardous Weather Testbed, NSSL, SPC, and Met Office are demonstrating that international collaboration can provide synergy, efficiency, and important scientific advances when it is strongly supported at both grassroots and institutional levels.

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