Question

In your own words, explain how Doppler radar works. Describe the properties of electromagnetic waves and interactions that make Doppler radar possible. (13 points)

Answer 1

If you stand up in a big room and echo, your voice will echo from the walls. As long as the room is empty. Since the speed of sound is constant, depending on air density, the more humid the air the faster and farther sound travels. The speed of sound is constant, you could measure the time it takes for your voice to echo off the walls. The same thing happens with Doppler radar, but it’s not voice, it has higher frequency signals.

Answer 2

Doppler Radar uses Doppler Effect as a principle to measure velocities, detect the presence of objects, identify meteorological phenomena and their intensity levels. This radar emits a continuous radio signal that allows the radar to differentiate between objects that are stationary and those in motion. This radar can be used, for example, to measure the speed of a particular object and to indicate its location, so that it is widely used in traffic surveillance.

Doppler radar is the most widely used type of weather radar that is currently of utmost importance for atmospheric monitoring. It is also employed for example in agriculture, air traffic and weather forecasting. Information gathered by radar assists meteorologists in early diagnosis of natural disasters.

Doppler effect, used by these radas, is a physical phenomenon observed in waves emitted or reflected by a source. It is perceived, for example, when listening to the sound of an ambulance passing by an observer. As the ambulance approaches, the tone becomes more and more acute, and as it moves away it becomes more serious. What happens is that we perceive a relative frequency, which is not the same frequency as the wave was emitted.