The Doppler Radar

 The Doppler radar is a modern weather radar that is used to see more than just clouds. It was named after J. Christian Doppler, who first proposed the idea of the "Doppler effect" when he noticed that a train horn was louder when stationary next to him compared to when it was moving away. The radar sends low frequency radio waves (pulses) into stormy areas to determine the velocity, distance, and direction of the wind or precipitation. It can also measure if the storm is moving away or towards the radar. A picture of it is shown below, containing a large satellite dish covered by a sphere to protect it from the elements.

    This forecasting process begins with a low frequency radio wave, or pulse, that is shot into a storm at a certain elevation. Once the pulse hits a raindrop, piece of hail, or a gust of wind the pulse breaks apart and many different waves shoot out in different directions. Using the Doppler effect, one wave will reach back to the satellite dish with a different frequency than what it started with. The back and forth interaction will usually last about 0.00000157 seconds. The forecasters can then measure the intensity of the storm by using the new frequency of the returning waves. If the pulse return with a high frequency, they can assume that the storm is intense, while a low frequency indicates a less powerful storm. The pulse also helps to find the horizontal distance of the storm, which is helpful in forecasting the storm on a map. The Doppler radar is important because it not only finds the distance of a storm, but it also finds the intensity. This can help predict future weather events and how detrimental they will be to certain areas. This can help communities properly prepare for any upcoming storms; whether it is closing windows of the house or evacuating.

    An example of the Doppler radar is the WSR-88D. Currently, it is the most powerful radar worldwide, possessing the strength of 750,000 watts. For perspective, this wave transmitter is 10,000 times more powerful than a lightbulb (75 watts). As most Doppler radars can only see one storm at a time, this model can see past more than one storm, giving information on further weather. The National Weather Service (NWS) owns one of these machines that sees 14 elevations every 5 minutes, giving one pulse every 20 seconds. This intelligent radar gives quick and accurate depictions on the weather, and what is to come.    

1. the Doppler effect: an increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other. The effect causes the sudden change in pitch noticeable in a passing siren, as well as the redshift seen by astronomers. (Definition from Oxford Languages)