Mesocyclone-Targeted Doppler Velocity Dealiasing

Abstract

he alias-robust variational (AR-Var) analysis developed originally for dealiasing raw velocities scanned from winter ice storms by operational WSR-88D radars was recently extended for dealiasing raw velocities scanned from all storms to increase the dealiased data coverage. The extended AR-Var (eAR-Var)-based dealiasing can detect tornadic mesocyclones and estimate their vortex center locations as by-products, but its dealiased data often leave rejected data holes in the critical vortex core and vicinity areas of detected mesocyclones. To solve this problem, a mesocyclone-targeted dealiasing routine is developed in this paper to perform two additional steps after the eAR-Var dealiasing. In particular, a reference check is performed in the first step, with the required reference velocities produced by a newly designed alias-robust vortex wind analysis to recover the rejected data in the vortex core, and then a continuity check is performed in the second step to recover the remaining rejected data around and beyond the vortex core. The mesocyclone-targeted dealiasing is tested extensively with severely aliased velocity data scanned from tornadic storms and is found to be effective and efficient for recovering the rejected data in and around the vortex core of the detected mesocyclone, provided the required data coverage conditions and analysis acceptance conditions are satisfied.