Doppler Radar

http://www.noaanews.noaa.gov/stories2004/s2311.htm

Doppler radar is radar that uses the Doppler effect to produce data about distance objects. According to the Merrian-Webster online dictionary, The Doppler effect is “a change in the frequency with which waves (as of sound or light) from a given source reach an observer when the source and the observer are in motion with respect to each other so that the frequency increases or decreases according to the speed at which the distance is decreasing or increasing.” One major use of the Doppler radar is in Meteorology. The map above features Hurricane Francis hitting the east coast of Florida.