Weather radar highlights of NSSL's first 40 years
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A tornadic vortex signature, the small red and yellow area indicated by the arrow, is visible in this horizontal scan of Doppler velocity data from the Binger tornado on May 22, 1981.

A tornadic vortex signature, the small red and yellow area indicated by the arrow, is visible in this horizontal scan of Doppler velocity data from the Binger tornado on May 22, 1981. (larger image)

The top image shows a WSR-88D vertical cross-section of radar reflectivity; the bottom image shows how dual-polarization techniques can better identify and quantify precipitation types and areas. The bottom color scale progresses from light, moderate, to heavy rain through rain/hail mix, graupel/sleet, hail, dry and wet snow, and ice.

The top image shows a WSR-88D vertical cross-section of radar reflectivity; the bottom image shows how dual-polarization techniques can better identify and quantify precipitation types and areas. The bottom color scale progresses from light, moderate, to heavy rain through rain/hail mix, graupel/sleet, hail, dry and wet snow, and ice. (larger image)

Further Advances: Dual Doppler And Pulse-Pair Processing

In 1974, a second 10-cm Doppler radar was constructed 26 miles northwest of the Norman Doppler radar. Known as the Cimarron Doppler radar (because of its location), it provided "dual-Doppler" capabilities. With both radars, scientists could see the same storm from two different perspectives, and pioneered studies on the structure of tornadic storms at different levels. Other advances included color displays and the development of pulse-pair processing, an efficient computational algorithm that uses pairs of pulses to compute Doppler velocity and display them in real-time (instead of days later).

Dual Polarization Technologies

Dual-polarization capabilities were added to the Cimarron Doppler radar in time for the 1985 spring storm season. Scientists had learned that when pulses were alternately polarized vertically and horizontally the return signal provided a clearer indication of cloud and precipitation particle size, shape and ice density — they could determine if the targets were round like hailstones or somewhat flattened like raindrops. This information had great potential to improve severe weather warnings.

 

National Weather Service implementation...