Examination of Tornadic Signatures Observed at Very Close Range using Simultaneous Dual-Polarization Radar at C band

On March 1, 2007 a tornadic supercell moved through the town of Enterprise, Alabama located in the Southeastern portion of the United States killing several people and causing damaged rated at EF3 (Enhanced Fujita scale). The tornado passed within 3 km of the Enterprise Electronics Corporation (EEC) radar manufacturing location. During this event, several hours of data were collected using the in-house EEC Simultaneous Dual-Polarization (SidPol) C-band radar. It is believed that this is the first dataset collected using polarimetric radar at C band for such devastating tornado event.

The purpose of the paper is to: 1) Document the general evolution of the storm into its tornadic phase with respect to the polarization variables. 2) Document hydrometeor classification of the storm based on radar observations compared to storm reports 3) Establish preliminary polarization signatures related to pre-tornadic development.

Preliminary analysis reveals small-scale polarimetric signatures associated with the tornadic debris at the tip of the hook echo and larger-scale polarization signatures attributed to strong azimuthal wind shear and rotation.

In addition to providing the basis of a dual polarization based tornado detection algorithm that can be applied at C band, the goal of this research could be extended further to S band and applied to the US WSR-88D polarization project and other S-band radar deployments.