Doppler Radar Colors
During World War II radar was developed to track enemy targets. Radar technicians noticed that the signals bounced off precipitation, too. From this accidental discovery the modern use of radar to track rain, sleet and snow gained widespread use. In 1964 Doppler radar -- named after the 19th century Austrian physicist Christian Doppler -- was invented and subsequently used by meteorologists to measure precipitation.
Other People Are Reading
-
Color Coding
-
Doppler radar measures precipitation's intensity, velocity, size and range. To break these different value types down and put them into an understandable format, a color-coded scale was developed. The basis for the scale is a measurement known as dBZ -- decibels of Z, where Z represents the energy reflected back to the radar -- and colors range from light green, indicating light precipitation (rain, sleet or snow) to a hot pink for extreme conditions. The higher the dBZ score, the more reflectivity exists and the greater the intensity of precipitation present.
Green to Red
-
Light and dark green indicate light and moderate precipitation levels that score 20 to 30 dBZ and a trace to 0.10 inch per hour rain or sleet falling rate. Yellow indicates a moderate, 36 dBZ, 0.25 inch per hour rate. Light brown has a 41 dBZ, 0.50 inch per hour rate. Orange indicates very heavy rain, scoring a 47 dBZ and 1.25 inches per hour rate. Red is used to indicate thunderstorms and a 52 dBZ, 2.5 inches per hour rain rate.
-
Rust to Hot Pink
-
In the color areas past red, conditions are extreme and perhaps dangerous. Rust indicates a rain rate of 4.0 inches per hour and a dBZ of 55. Dark brown indicates a very heavy thunderstorm with hail possible. It scores 60 dBZ with a rain rate of 8.0 inches per hour. At the top end of the scale is hot pink. This color indicates the most severe of storms at 16.0 or more inches of rain per hour with a dBZ of 65.
Tornadoes
-
Advance warnings can save lives. In 1973 a tornado devastated the town of Union City, Oklahoma. As scientists watched the event on Doppler radar they discovered the tornadic vortex signature. As a tornado forms the winds blow raindrops in a circular pattern. By studying the event, the researchers identified this pattern in the clouds prior to the tornado lowering and continue to use this information to warn people on the ground in advance of a possible tornado touchdown.
-
References
Resources
- Photo Credit Jupiterimages/Photos.com/Getty Images
