SCIENCE: Inside a Doppler radar

Ever wonder what the inside of a weather radar looks like?

There are 155 National Weather Service (NWS) and Department of Defense Doppler radar sites spread across the United States and its territories, including Guam and Puerto Rico. These radars work nonstop, 24 hours a day, 7 days a week. They always need to be in tip-top shape for potential weather. That means regular maintenance is required, but they can only be worked on during a stretch of beautiful and uneventful weather.

Radar stands for Radio Detection And Ranging, and has been utilized to detect precipitation (rain, snow, hail, etc.) since the 1940’s. The current radar system used by the NWS is called the WSR-88D, which stands for Weather Surveillance Radar – 1988 Doppler. The prototype for this radar was developed in 1988. This is the first time the Doppler effect was utilized to see rotation among other features in a thunderstorm. This has greatly improved meteorologists’ ability to analyze and forecast, especially during severe weather.

Recently, the Doppler radar in Great Falls, Mont. needed maintenance as part of their Service Life Extension Program (SLEP). Meteorologist Roger Martin shared his experience with the WBRZ Weather Center.

It's not too much of a climb. The radar isn't as tall as some of the others across the country.

Top of the stair looking back towards the office. The building in the foreground is the weather balloon shelter. We have one like this at our local office in Slidell. They NWS launches balloons twice per day from each station.

Here's another view from the top looking southwest toward the Rockies. There are some showers developing over the large mountains in the center of the picture.

There is a hatch at the top of the stairs where meteorologists climb into the radar. There's even a winch to haul stuff up.

This is the inside wall of the radar dome. It has a "soccer ball" look.

Once you're inside the "soccer ball," you can see one large antenna pressed up almost right against it. This antenna constantly rotates around and gradually tilts up with each successive sweep to give us a profile of approaching storms, from top to bottom. One complete scan at all tilts is called a "volume scan." Each volume scan takes about four to six minutes to complete.

This antenna is 2x-3x the average person. It's balanced so perfectly though that it can easily moved by hand.

This is what the other side of the antenna looks like. This is the part that emits the pulses from the radar. The average transmitted power is about 450,000 watts (compared to 1000 watts on a kitchen microwave).