Innovative Radar System Sees Tornadoes, Saves Lives

Achievement date: 

A new type of low-altitude radar network developed at the NSF-funded Engineering Research Center (ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) helped rescue workers in Newcastle, Oklahoma stay clear of an EF-4 tornado on May 24, 2011. The conventional NEXRAD system wasn’t able to track the twister when it suddenly changed direction and disappeared inside heavy rain. Fortunately, this experimental system helped the National Weather Service storm spotters find the tornado quickly and may have saved several lives.

CASA, headquartered at the University of Massachusetts Amherst, is working in collaboration with several academic and industrial partners across the United States to create the next generation of weather detection systems. The event in Newcastle marked a successful demonstration of the system by the University of Oklahoma, a CASA partner institution, as it performed with much greater accuracy and speed than the conventional radar, proving its value in detecting low-altitude weather phenomena such as tornadoes.  Onsite lead storm spotter Lee Kuhlman said, “It completely changed our target area. The emergency manager got on the radio, and with literally minutes to spare, got EMS and fire personnel to move, possibly out of the way of the storm.’’


This country’s NEXRAD Doppler radar system is regarded as the best in the world, but it has some important shortcomings. The current network consists of 159 large radars spread across the country, with roughly 200 miles between the towers. It allows for large-scale monitoring across multiple states, but falls short when localized, high-resolution imaging is necessary.

CASA’s work seeks to improve radar weather detection in several ways. While NEXRAD takes five minutes to complete a 360-degree sweep, the CASA system does it in fifteen seconds. NEXRAD radars are mounted high and sparsely distributed, resulting in low resolution and accuracy and a dropout of signal returns at lower altitudes as distance from the radar increases. The CASA system uses overlapping radars placed much closer together that can be mounted on top of small towers or two-story buildings.

The CASA system uses X-band frequencies, which are shorter and more energetic than standard radar microwaves, thereby improving resolution and data throughput. Following successful implementation and demonstration of their system, the researchers aspire to create a national network consisting of several thousand X-band radars that feed into a centralized data server. The team has also addressed the potentially high cost associated with this new system, reducing costs to only 10% what the US military currently pays for similar technology.