Most people are familiar with this type of map, a Doppler Radar Map. However, as the site that this image was found on points out, the Doppler Radar Maps that we are most familiar with are actually "reflectivity images." With Doppler Radar, a radar pulse is sent out, the frequency is measured, and the results indicating the velocity of precipitation are represented through colors. Although there are no steadfast rules for color usage, the colors are often assigned similar to the actual shifts seen when the Doppler effect is applied to visible light...red, orange, and yellow indicates raindrops blowing away from the radar antenna; green, blue, and violet indicates raindrops blowing toward the radar antenna.
