What is a Doppler radar like?

A Doppler radar is a unique and specialized radar.  It performs its ‘weather watch’ functions by making use of the Doppler effect.  This enables it to produce velocity data relating to objects present at some distance. A Doppler radar can be seen when driving through U.S 41 between Marquette and Negaunee. The Doppler radar is one of the most powerful weather monitoring devices used by the National Weather Service in the U.S.

How does Doppler radar works?

video of how a doppler radar works

Source: National Weather Service How the Doppler Radar Works

Doppler radar performs its velocity data production by bouncing a microwave signal from a selected object. Then it analyzes the alterations contained in the frequency of the object’s returned signal by means of motion. This is the means through which scientists obtain direct and accurate measurements of a particular object’s velocity compared to the Doppler radar.

Doppler radars are used in different fields such as aviation, sounding satellites, police speed guns, radiology, healthcare, bistatic radars, and meteorology.

Doppler radar and use of the Doppler Effect

All Doppler radars use the Doppler Effect to accurately measure the radial velocity of targets in the directional beam of the antenna. The Doppler Effect is a phenomenon named after Austrian physicist, Christian Doppler.  He is the brain behind the phenomenon. The Doppler effect is an experience which can be likened to what happens to a moving train.

map of the radar of a storm

Source: NOAA

The whistle on the train changes to high when the train is in motion and is low when the train is stationary. These happen when the sound waves are compressed increasing the pitch of the whistle as the train approaches. When they are stretched, it decreases the pitch of the whistle as the train moves away from you.

A similar effect is what happens in the atmosphere when an energy beam strikes an object and is reflected back to the Doppler radar. The computer of the radar measures the phase change of the reflected. Then it converts such change to the object’s velocity, either from or towards the radar. In other words, the Doppler effect shifts the received frequency upwards or downward. Depending on the closing or opening of the target’s velocity in the beam, it allows a direct and highly accurate measurement of target velocity.

Doppler radar is unique in keeping tabs on the weather, and knowing how it works is vital to know how best to rely on it.

The Procedural working pattern of a Doppler radar

In atmospheric study and measurements, a Doppler radar is regarded as one of the most potent tools for detecting rainfall within a particular area. The radar starts to work by means of sending out beams in a circular pattern all around the radar itself. Once any of the beams make contact with a raindrop or hailstone, part of the beam is reflected back towards the radar. Immediately the radar receives the reflected beam. It calculates the distance of the precipitation and equals its intensity, depending on the size and speed of the drop.

The radar also has the ability to identify the directional movement of the precipitation in the event it is windy. The next step taken by the radar is to translate the distance and the intensities into graphical maps.  These maps can easily be viewed and displayed on the television.

Doppler radar is extremely accurate in recording wind speed and general weather activities on sea and land.

Image Resource: Featured Image Source https://www.spc.noaa.gov/faq/tornado/doppler.htmhttps://www.youtube.com/watch?v=WrNNb4wHDMg, http://www.crh.noaa.gov/Image/lmk/soo/Radar_Web_Images/

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