Doppler Radar

http://www.noaanews.noaa.gov/stories/s1192.htm

Doppler Radar is a radar primarily used in weather forecasting which uses the doppler effect to display velocity data of wind speeds by taking both the linear and radial velocities of a weather system. It does this by sending pulses of radiation. This is what produces the circular image of the hurricane seen above in a doppler radar of hurricane Claudette on the coast of Texas in 2003. As you can see, the eye of the hurricane is just north of Corpus Christi up the coast.