Kinematic and Polarimetric Radar Observations of the 10 May 2010, Moore-Choctaw Oklahoma, Tornadic Debris Signature

Abstract

ornadoes are capable of lofting large debris that present irregular shapes, near-random orientations, and a wide range of dielectric constants to polarimetric radars. The unique polarimetric signature associated with lofted debris is called the tornadic debris signature (TDS). While ties between TDS characteristics and tornado and storm-scale kinematic processes have been speculated or investigated using photogrammetry and single-Doppler analyses, little work has been done to document the three-dimensional wind field associated with the TDS.Data collected by KTLX and KOUN WSR-88D S-band radars as well as the University of Oklahoma?s Advanced Radar Research Center?s OU-PRIME C-band radar are used to construct single- and dual-Doppler analyses of a tornadic supercell that produced an EF-4 tornado near Moore and Choctaw, Oklahoma, on 10 May 2010. This study documents the spatial distribution of polarimetric radar variables and how each variable relates to kinematic fields such as vertical velocity and vertical vorticity. Special consideration is given to polarimetric signatures associated with subvortices within the tornado. An observation of negative differential reflectivity (ZDR) at the periphery of tornado subvortices is presented and discussed. Finally, dual-Doppler wind retrievals are compared to single-Doppler axisymmetric wind fields to illustrate the merits of each method.