Convective Meteorology (Mesoscale Dynamics)

Kinematic Observations of the 10 May 2010 Moore, OK Tornadic Debris Signature

Casey B. Griffin

School of Meteorology

05 February 2016, 3:00 PM

National Weather Center, Room 5600
120 David L. Boren Blvd.
University of Oklahoma
Norman, OK

The ability of tornadoes to loft non-meteorological scatters that present irregular shapes and sizes, near random orientations, and a wide range of dielectric constants allow polarimetrically diverse radars to discriminate between meteorological scatterers and tornadic debris. The unique polarimetric signature associated with lofted non-meteorological scatterers is called the tornadic debris signature (TDS). Previous studies have identified that the TDS is characterized by a large range of radar reflectivity factors (Z_HH), low values of copolar cross correlation coefficients (ρ_hv), and differential reflectivity (Z_DR) values near zero. Previous work has also documented that tornado damage measured using the enhanced Fujita scale (EF) rating correlates well the magnitude of reflectivity within the TDS as well as the height and volume of the TDS. While ties between TDS characteristics and tornado- and storm-scale kinematic processes have been speculated or investigated using single-Doppler analyses, little work has been done to document the three dimensional wind fields associated with an evolving TDS.

This study uses 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 to construct dual-Doppler analyses of a tornadic supercell, which produced an EF-4 tornado near Moore, OK on 10 May 2010. Dual-Doppler analyses will be used to examine two and three-dimensional flow near and within the TDS during various stages of the tornado’s lifecycle. Specifically, this seminar will focus on the spatial distribution of polarimetric radar variables and how the variables relate to vertical vorticity. Special consideration will be given to a time when multiple vortices were observed within the tornado and how the polarimetric variables relate to these vortices.

Convective Meteorology (Mesoscale Dynamics) Seminar Series website