Morse Code of Weather: history of weather radar, from WWII technology to present day applications

Published: Jul. 30, 2022 at 9:14 AM CDT
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BISMARCK, N.D. (KFYR) - During our deep dive radar series over the past six weeks, we’ve taken you inside of the Bismarck National Weather Service’s radar to explain the basics of how it works, talked about how it tilts to different angles to create a three-dimensional picture of the atmosphere, discussed how maintenance is performed, explained the Doppler and dual polarization technologies that radars use to see inside of storms, and finally talked about some limitations of our current radar network.

But how did we get to this point of radar technology and what’s in store for the future? Here’s a brief history of weather radars.

The underlying principle of all radars was first observed in 1886 by Heinrich Hertz when he found that electromagnetic waves could be reflected off of various objects, and even focused into beams by appropriate reflectors.

Various research projects continued on radar’s potential applications and by 1930, Lawrence Hyland with the Naval Research Laboratory discovered that an airplane flying over his radio antenna caused changes in the signals that it received.

In 1935, Robert Watson-Watt used pulsed radio frequency energy to observe targets at longer ranges — up to 90 miles away.

By World War II, radar was used by militaries around the world, scanning for incoming airplanes. But the use of radar for weather observations occurred by accident as military radar operators noticed that precipitation was showing up on their displays along with their intended aircraft targets.

After the war, the National Weather Service received 25 radars that had been used by the Navy, and in 1959, the weather service began rolling out its first network of radars, called the Weather Surveillance Radar, or WSR-57, as it was designed in 1957 using World War II technology. It gave only coarse reflectivity data and no velocity data, which made it extremely difficult to detect tornadoes. Precipitation was traced across the radar screen using grease pencils and forecasters had to manually turn a crank to adjust the radar’s scan elevation.

Radar image on WSR-57 of tornado-producing supercells over Minneapolis, 1965
Radar image on WSR-57 of tornado-producing supercells over Minneapolis, 1965(NOAA)

An updated version, the WSR-74, supplemented and replaced the older radars beginning in 1977 with newer and more reliable components. 128 of the WSR-57 and WSR-74 model radars were spread across the country, including in North Dakota, and operated as the weather service’s radar network until the 1990s.

Network of WSR-57 and WSR-74 radars
Network of WSR-57 and WSR-74 radars(National Weather Service Modernization Committee)

Meanwhile, in the 1980s, researchers began developing the Next Generation Radar System, or NEXRAD, that would incorporate the use of Doppler technology. This was a big step forward for meteorologists, allowing them to detect the speed and direction of precipitation within storms.

These WSR-88D radars, with the D standing for Doppler, were deployed operationally beginning in 1992. The resolution of the data was much higher with these radars and severe weather was easier to pinpoint. The Bismarck WSR-88D radar was installed in 1994 and radar technology has continued to improve since then with several upgrades to the nationwide network, especially with the introduction of dual-polarization technology that has happened over the past 10 years.

Chauncy Schultz, science and operations officer at the Bismarck National Weather Service, said: “It’s one of the hallmark changes in technology within the meteorology field within our lifetimes. Prior to the mid-1990s, when these new radars were installed, the lead time, how much advanced notice you would get for a warning was mere minutes on average. Now, it’s 10 minutes, 20 minutes, leaps and bounds thanks to the installation of the radars, all of the new technology, and other research that we’ve learned since then, of course. But the radar instillation was the hallmark turning point in improving warnings in the United States.”

155 NEXRAD radars are now positioned across the county, with most of them either collocated with National Weather Service offices or near Air Force Bases, as is the case with the radar northeast of Minot. Even though the NEXRAD radars have now exceeded their original lifespan estimate of 20 years, the radars are currently undergoing a Service Life Extension Program to keep them operating into the 2030s.

Worldwide WSR-88D NEXRAD radar network
Worldwide WSR-88D NEXRAD radar network(NWS)

But in the meantime, private companies such as Climavision have stepped in to try to help fill in some of the gaps in the existing National Weather Service radar network with their own proprietary radars. And future radar technology, such as faster scanning phased array radars that can be steered electronically, giving users the ability to control how, when and where the radar scans is being researched and developed.

Multi-Function Phased Array Radar
Multi-Function Phased Array Radar(NOAA National Severe Storm Laboratory)

Wrapping up this series, I hope you now have a deeper appreciation of weather radar technology that many of us take for granted and think about how radars work the next time you load up the radar on our app or see us use radar on-air.

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