An Improved Automated Velocity Dealiasing Algorithm for Doppler Weather Radar

To improve velocity dealiasing performance in strong wind shear zones and distant isolated echo regions, as well as to mitigate the impact of velocity noise, an improved velocity dealiasing algorithm has been developed based on the method proposed by Xiao,et al. (2012).The key enhancements include: 1)?To improve performance under intense horizontal wind shear, steps utilizing horizontal neighborhood dealiasing and a radial-then-tangential sequence were inserted between the first and second rounds of full-azimuth radial dealiasing?(which employed a tangential-then-radial sequence in the original algorithm).2)?For distant isolated echo regions, vertical neighborhood dealiasing was added following horizontal neighborhood dealiasing.3)?A noise filtering process was implemented after all dealiasing steps to mitigate the impact of noise on the identification of small-scale convergence, divergence, and vortex features. The velocity dealiasing performance of both the original and improved algorithms was analyzed using four severe weather cases. The improved algorithm was further tested and evaluated using?3519 volume scans?of tornadoes, squall lines, isolated severe storms, and typhoons observed by S-band Doppler weather radars. The results demonstrate that the improved algorithm effectively resolves velocity aliasing in strong wind shear zones and distant isolated echo regions—challenging scenarios for the original algorithm—while significantly mitigating velocity noise artifacts. The dealiasing accuracy nearly approaches 100%, with residual aliasing or improper corrections occurring only under clutter-contaminated conditions or in small, isolated echoes at long ranges. The enhanced algorithm demonstrates superior performance over the original method, robustly handling diverse velocity aliasing and noise interference.