Figure GT.27

Doppler radar. (A) Doppler radar works by beaming microwaves, which reflect off falling precipitation (rain, snow, hail, and sleet) in the sky. An image is developed based on the reflected energy. (B) Hurricane Irene’s spiral structure is clearly visible in this August 27, 2011, Doppler radar image of the U.S. East Coast centered on Virginia and North Carolina. Reds and yellows indicate heavy rainfall; greens and blues show regions of relatively less rainfall.

(B. National Weather Service)