The algorithm successfully deals with range and velocity ambiguities

Team resolves Doppler Dilemma

Researchers and engineers from NSSL and the National Center for Atmospheric Research (NCAR) have successfully developed an algorithm that deals with range and velocity ambiguities in WSR-88D measurements.

Weather radars have long been plagued by what is known as the “Doppler Dilemma.” Since ambiguities in range and Doppler velocity measurements are connected, trying to alleviate one worsens the other. Proper censoring of contaminated or invalid data is essential for the WSR-88D to be useful for forecasters and automated algorithms.

The Radar Operations Center of the National Weather Service sponsored NSSL and NCAR to find methods to deal with this problem. A phase coding algorithm, SZ-2 (named for NSSL developers Sachidananda and Zrnic) is the result. NSSL's Sebastian Torres solved the issues of integration into the surveillance and Doppler scanning modes and incorporated ground clutter filtering and estimation of spectral moments.

SZ-2 is now undergoing beta testing on the NWS operational radar in Oklahoma City, and will soon be implemented on the national network of WSR-88D radars.