P1.16 THE NATIONAL SEVERE STORMS LABORATORY: 40 YEARS YOUNG AND GOING STRONG

Rodger A. Brown Keli Tarp NOAA, National Severe Storms Laboratory NOAA Public Affairs Norman, Oklahoma Norman, Oklahoma

1. INTRODUCTION WSR-57 radar was monitoring the storms In 1964, a small group of researchers started continuously and measuring the reflectivity. This a new organization that would forever change the research led to improved commercial airline safety severe storm scene in the United States and guidelines in the vicinity of thunderstorms that are around the world. The U.S. Weather Bureau’s still in use today. National Severe Storms Project (NSSP) moved from Kansas City to Norman, Oklahoma and 3. WEATHER RADAR RESEARCH AND changed its name to the National Severe Storms DEVELOPMENT LEADING TO WSR-88D Laboratory (NSSL). The mission of the laboratory is to increase scientific understanding of severe The very foundation of today’s National storms that leads to better forecasts and warnings Severe Storms Laboratory lies in weather radar of hazardous weather conditions. research and development that began before its During its first 25 years, NSSL continued formation in 1964. Part of NSSL’s initial role was NSSP’s (and its predecessors’) long-standing to maximize the use of the WSR-57 surveillance tradition of improving understanding of severe radar for the Weather Bureau. NSSL continues to storms by conducting a data collection program push the weather research community to the edge each spring that included surface and upper air through its research and development efforts such mesonetworks, research aircraft, and radars. as Doppler radar, operational WSR-88D Doppler Over the years, Doppler radars (including dual radar and now dual polarization and phased array polarization), an instrumented TV transmitter radar. tower, storm intercept teams, and storm electricity In the late 1960s, NSSL obtained a surplus measurements were added. In recent years, 10-cm Doppler radar that had been used by the spring programs have become more intermittent U.S. Air Force. In the early 1970s, use of this because of funding constraints, with many radar led to an historical discovery. The Union associated with national research programs City tornado of 24 May 1973 was a significant (involving airborne Doppler radars) in the southern event in the history of weather research and Plains. Since the early 1990s, various NSSL warning. NSSL’s storm intercept team was in the sensors have become mobile with the addition of vicinity of the tornado and they were able to mobile rawinsonde release vehicles, balloon- document the entire life cycle of the tornado on borne storm electricity sensors, mesonetwork film. Researchers used the Norman Doppler instruments on the tops of cars, and Doppler radar to collect data within the tornadic storm. radars mounted on trucks. They found a definitive signature of the tornado in the Doppler velocity data. Their discovery of what 2. EARLY SUCCESS – IMPROVED AIRLINE is now known as the tornadic vortex signature had SAFETY a major impact on the development of the national network of Doppler radars. Early NSSL research has had a positive NSSL Doppler radar studies of thunderstorm impact on improved public safety. Aircraft studies mesocyclones and tornadoes during the 1970s, of turbulence in severe thunderstorms, called including the Joint Doppler Operational Project, Project Rough Rider, during the 1960s, 1970s, proved Doppler radar could improve the nation’s and early 1980s, involved aircraft flying into ability to warn for severe thunderstorms and thunderstorms measuring the turbulence while the tornadoes. This led to the decision in 1979 by the ______National Weather Service (NWS), U.S. Air Force’s Air Weather Service, and Federal Aviation Corresponding author address: Dr. Rodger A. Brown, Administration (FAA) to include Doppler capability National Severe Storms Laboratory, Norman, OK 73069. in their updated operational WSR-88D and E-mail: [email protected]. Terminal Doppler Weather Radar (TDWR) net- works. The WSR-88D has helped forecasters Additional highlights of NSSL’s radar work significantly improve severe thunderstorm and include design and software development for tornado warnings, saving countless lives. In 1995 WSR-88D’s Open Radar Product Generator, the NSSL received a gold medal from the Department Open Principal User Processor, and the Open of Commerce for work leading up to, and its Radar Data Acquisition Unit. These open system ongoing support of, the national WSR-88D approaches allow the WSR-88D system to be deployment. more easily modified and updated. More recently, through a program called 4. CONTINUING TO IMPROVE WSR-88D CRAFT—the Collaborative Radar Acquisition Field Test—researchers in Norman and else- Researchers have been working on an where were able to prove that Internet access to upgrade to current radar technology for about 20 high-resolution data from multiple radars is years. Dual-polarization capability—where pulses technically possible and economically viable. As a are alternately polarized vertically and horizon- result, high-resolution radar data from the national tally—was added to NSSL’s second 10-cm network of WSR-88D radars is now available over Doppler radar (located at Cimarron Field 26 miles the Internet in near real-time for use by northwest of Norman) in time for the 1985 spring government, university and private sectors. storm season. Dual-polarized radar has three primary benefits. First, it improves data quality, 5. MOBILE RESEARCH CAPABILITIES since nonmeteorological artifacts, such as birds and insects, can be removed. Second, it will help For the past 20 years or so, NSSL has been forecasters make more accurate flood forecasts, involved in developing mobile facilities to take because it improves the user’s capability to instruments to the storms rather than waiting for estimate how much rain is falling. Third, it allows the storms to come to the instruments. Mobility forecasters to discriminate between rainfall, has proven to be a key to NSSL’s scientific snowfall, hail and other types of precipitation success. The two greatest accomplishments in particles. this area have been mobile mesonetworks that Dual polarization, which has been tested on have allowed researchers to make measurements NSSL’s new research and development WSR- beneath storms as they move with the storms, 88D (KOUN) and shared with the Norman NWS and mobile ballooning that has allowed scientists forecast office for several years, has proven to put instruments into the desired regions of useful for forecasters. Dual polarization tech- storms. nology is scheduled as an upgrade to the The type of research that has gained the operational WSR-88Ds within the next five years. most attention has been the study of tornado Starting in the mid-1980s, NSSL researchers development and evolution through a project made automated Doppler radar data available to called VORTEX—Verification of the Origins of National Weather Service forecasters. Various Rotation in Tornadoes Experiment—that ran algorithms were developed that detected and during the springs of 1994 and 1995. VORTEX notified forecasters of hail, mesocyclones, tornado utilized the mobile facilities to a great extent and circulations, downbursts and gust fronts, and with great success. The project deployed a team tracked the movement of storms. These of investigators who operated a dozen mobile algorithms were later combined with a display mesonet vehicles, two mobile laboratories, a system and became known as the Warning mobile Doppler radar and two Doppler-equipped Decision Support System (WDSS). aircraft. VORTEX produced a number of high WDSS was primarily a single radar based quality data sets of tornadic and nontornadic system. To incorporate multiple radars into a supercell thunderstorms that led to several regional mosaic with other data, a new system important new findings. called WDSS-II was developed. NSSL research- In partnership with the University of ers have integrated sources of information from Oklahoma, Texas A&M and Texas Tech, NSSL other sensors, including satellite and lightning recently developed the Shared Mobile information and near-storm environment data from Atmospheric Research and Teaching Radar, or numerical models. All of these data streams have SMART-R, a mobile 5-cm Doppler radar. Two been combined in order to help forecasters make SMART-Rs have been used to study tornadoes, better and more effective and efficient warning hurricanes and other phenomena across the decisions. country.

6. NUMERICAL MODELING methodology to improve estimates of precipitation in Arizona over complex terrain. The concept was By the mid-1980s, NSSL had begun to then turned into an algorithm that has world-wide develop an expertise in numerical modeling. applications. Various techniques, including ensembles, are The Lab’s technique is different from being investigated today to improve the numerical traditional quantitative precipitation estimation prediction of storm-scale, mesoscale, and (QPE) because of its multisensor approach that synoptic-scale processes. NSSL researchers integrates sensors such as satellite data, rain made a tactical decision 15–20 years ago that gauges and model data, together with radar data, they wouldn’t develop their own models—rather, and combines them in a physically sound way. they would use existing models and make them Improved estimates of precipitation are expected better. to help forecasters improve the timeliness of flash NSSL uses numerical modeling in two ways. flood warnings. First, they use models to simulate the evolution of Today NSSL is heading a project to seam- severe storms. They try to understand what is lessly integrate all National Weather Service and going on in terms of the physical processes within Department of Defense WSR-88D radars across the storms. Second, they use numerical models to the U.S. into a single mosaic, thus providing the forecast the weather. NSSL researchers are now first high-resolution depiction of storms and developing ensemble techniques to use with quantitative precipitation estimation from coast to models. Ensembles are a collection of model coast in real time. results that were created by varying the model initial conditions and/or model parameters to 9. INTERNATIONAL COLLABORATIONS produce a suite of forecasts and probabilities. NSSL conducts collaborative research efforts 7. SUPPORTING THE STORM PREDICTION with other countries. For example, there have CENTER been studies of the summer monsoon that brings most of the annual rainfall to the southwestern In 1997, soon after the National Severe U.S. and northern Mexico. Forecast models do Storms Forecast Center in Kansas City changed not handle precipitation estimation very well owing its name to the Storm Prediction Center (SPC), it to the sparsity of surface and upper air moved to Norman. This deliberate move to observations over Latin America. For nearly a collocate research with operations has resulted in decade, an NSSL researcher has been influential many opportunities for NSSL meteorologists to in augmenting the observational network by help SPC forecasters develop improved severe obtaining rain gauges and recycled theodolites for storm forecasting techniques, including the tracking upper air balloons and by training local application of probabilistic forecasting techniques. inhabitants how to use the instruments. Collaboration with the SPC has broadened the focus of NSSL researchers to include the study of 10. OUTREACH ACTIVITIES hazardous winter weather and its effects on the population, as well as the study of processes that Research at NSSL has impacted people take place inside those storms. beyond the weather research community—from emergency managers and storm spotters to the 8. IMPROVING PRECIPITATION ESTIMATES media and the general public. Much of the work at NSSL has been accomplished with the help of NSSL has also addressed precipitation students, many of whom have gone on to very forecasting issues through hydrometeorological successful careers with leading meteorological research since the mid-1990s. The work started organizations throughout the world. For the past with the Salt River Project, a power and water several years, the Lab has cultivated future utility based in Phoenix, Arizona. The utility researchers through the Research Experiences noticed that estimates of rain and snow were not for Undergraduates program, a National Science very good for operational purposes in the cool Foundation sponsored program that is run through season. It asked NSSL to take a more detailed the University of Oklahoma. Each summer, about look at the problem because accurate estimates 10 college students from across the country are of precipitation are important to utilities that use paired with scientists throughout the Norman hydropower to generate electricity. NSSL meteorological community, including NSSL, to researchers subsequently came up with a work on a research-directed program. At the end of the 10 week program, the students each write a Researchers and forecasters can then improve paper and give a presentation. The program gives conceptual storm models and use the radar data them a chance to see most of the aspects of a to initialize and improve stormscale computer research career. models. In addition, the FAA is supporting Outreach efforts at NSSL also include a research to see if the radar can have a dual use— newsletter, work with a television program for for both weather surveillance and aircraft tracking. middle school students called “Passport to It is expected to take 10 to 15 years to move the Knowledge,” consulting on the movie “Twister,” phased array radar from research and develop- posters about downbursts, lightning and ment to technology transfer and deployment. tornadoes, interviews with local and national news media, interviews with production companies for 12. SUMMARY programs that have aired on the Discovery Channel, National Geographic and The Weather Established in 1964, NSSL leads the way in Channel, as well as numerous open houses and investigations of all aspects of severe and tours for schools and special groups. hazardous weather. NSSL is part of NOAA Research and is the only federally-supported 11. RADAR OF THE FUTURE laboratory focused on severe weather. NSSL’s scientists and staff continue to explore new ways NSSL, with the help of its partners, the Navy, to improve understanding of the causes of severe Federal Aviation Administration, the University of weather and ways to use weather information to Oklahoma, the Oklahoma State Board of Regents, assist National Weather Service forecasters, as the National Weather Service, Lockheed Martin, well as its federal, university and private sector and Basic Commerce and Industries, is now partners. leading radar technology into the future with the Through its various research activities during National Weather Radar Testbed located in the past 40 years, NSSL has been instrumental in Norman. This phased array Doppler radar system advancing the state of the art of severe storm is the first facility of its kind to be available on a detection, warning and prediction. Its accom- full-time basis to the radar research community. plishments are long and varied, and the list of Phased array radar could be the next what it hopes to do is even longer. Overall, NSSL significant technological advancement to improve has significantly contributed to saving lives. our nation’s weather services. This technology NSSL’s greatest asset has always been its has a unique antenna that allows the collection of employees and its focused mission. the same amount of information as conventional radar, but five to six times faster. Scientists will be Acknowledgments. We appreciate the assistance able to adapt the radar scan to focus on the most of the many present and former staff members important weather features and gather high who contributed information for and commented temporal resolution storm information that will on this historical discussion. improve the understanding of storm evolution.