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How Does Weather Radar Work? We Have You Covered!

2 May 2017, 5:05 pm

One of the many images you see on WeatherNation is Radar. Radar [which stands for RAdio Detection And Ranging], is an integral tool for meteorologist, and provide vital information for severe weather, nighttime forecasting, and much more.

But how do they work?

Radar did not start off as a meteorological tool, rather a military detection instrument.  During WWII, it was used by the British and American Militaries to find enemy airplanes before they attacked. These surveillance Radar work similarly to meteorological radars, and kind of act like how bats “see”. The Radar will send out a wave like pulse out from a part of the Radar called an antenna. Many pulses are sent out in all directions and at all heights, at the same time. This kind of antenna is called Doppler, hence Doppler Radar.

(Image: U.S. Air Force)

These pulses will keep moving through the air till it hits a target (like an airplane or a cloud). The pulse will then bounce off of the target and start moving back from the target to the Radar. Radars look like domes so that they can collect return pulses from every direction, and funnel themselves into a receiver. A single pulse will provide information such as the time the pulse was sent out, the time the pulse was brought back, and the location of the pulse. After going through the receiver, this information goes through a computer algorithm, and are stitched together to produce a picture, just like you see on WeatherNation. This all happens in the span of a few milliseconds!

(Image: NOAA)

The targets that meteorologist want to hit are water vapor, dust, and debris. Water vapor is what makes up things like clouds, rain, snow, and fog. Dust and debris can give us information about things we can’t see, such as winds, rotation, and tornadoes. The size and consistency of the target will determine at what frequency the pulses are sent out. Doppler Radar is sent out at 1-2 GHz, which is much higher than what humans can hear (20Hz-20kHz). This is why you can’t hear Radar.

Radars work 24 hours a day, 7 days a week. This is super important because weather happens all the time. Radar can help detect characteristics of tornadoes for a spotter can, determine the path of precipitation during the night, and see what weather is happening states away.

Headline image: Norman Doppler Radar Installation – National Severe Storms Laboratory (NSSL) Collection

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