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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.
This radar was used in a field project run by the National Center for Atmospheric Research in Taiwan.
Click on image for full size
Image courtesy of the University Corporation for Atmospheric Research

How Radar Works

Radar is short for "radio detection and ranging". A transmitter emits pulses of high frequency electromagnetic waves (radio waves). These waves strike conductive objects and are backscattered to the receiver. A radar echo shows up on a monitor and shows where the object is located.. A computer measures the time it takes for the signal to reflect off the target and then calculates how far away it is.

Radar is used extensively in the military as both an offensive and defensive weapon. Aggressors can use radar to locate areas where they want to attack. Defenders can use radar as an early warning of an impending attack. New stealth technology has begun to make current radar systems useless because of the way objects are designed to not reflect radar waves. One drawback to using radar in a battle situation is that detection is a two way street. If you use radar to try and find an enemy, that enemy will know where you are. This is just like using a flashlight in the dark.

There are many scientific uses of radar, but the most well-known by the public is weather radar. Weather radar is an important forecasting tool, especially for very short-term forecasts. Radar is also used to study other aspects of the atmosphere, such as mapping wind patterns. For example, if scientists know how the wind is blowing in the upper atmosphere, they can predict what areas could be affected by air pollution. Planetary probes such as Magellan also use radar for surface mapping missions.

Last modified June 11, 2010 by Becca Hatheway.

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The Fall 2009 issue of The Earth Scientist, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earth’s ancient atmosphere, is available in our online store.

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