Book 7, Question 74
Why Do Doppler Radars See Rain Before It Arrives?
Doppler radar sends out pulses of radio waves and listens for the echoes that bounce back. Raindrops, hail, and snow bounce those waves back, so radar can see precipitation far away, often more than 100 kilometers. That lets forecasters spot storms long before they arrive.
From the book
Page from A Million Whys Book 7
More fun facts
- The United States has a network of 160 Doppler weather radars called NEXRAD.
- NEXRAD is run together by the National Weather Service, the Federal Aviation Administration, and the Department of Defense.
- Each radar is called a WSR-88D, short for Weather Surveillance Radar, 1988, Doppler.
- Doppler radar can measure winds as well as rain, snow, and hail, which helps spot tornadoes.
- Radar also picks up things that aren't weather, like flocks of birds and swarms of insects.
- In 2008, the radars were upgraded to show finer detail, called Super Resolution.
Questions kids ask
How many weather radars does the U.S. have?
The NEXRAD network has 160 Doppler radars.
Can weather radar see birds?
Yes. It can pick up birds and insects as well as rain and snow.