Dual-frequency simulations of radar observations of tornadoes

Tornadic debris signatures (TDSs) have exciting potential for scientific research and operational forecasting. TDSs provide remote tornado detection and damage estimation capability, and may provide new information about scatterer characteristics in tornadoes. To exploit these new opportunities, it is critical to obtain a better understanding of statistical properties of TDSs, and understand how multiple frequency polarimetric radar measurements may benefit these new capabilities. In this study, we examine statistical properties of TDSs using S- and C-band polarimetric radar data with comparisons to damage surveys and satellite imagery. Using serendipitously, closely matched radar scans at S and C bands during the 10 May 2010 Moore-Oklahoma City EF-4 tornado, statistical analyses of polarimetric variables are performed to evaluate similarities and differences between these wavelengths in TDSs. Interesting polarimetric radar signatures within TDSs, such as negative differential reflectivity (ZDR) and high co-polar cross-correlation coefficient in the vortex center, will be discussed. Finally, using output from a Large-Eddy Simulation (LES) model, debris trajectories are calculated to model statistical properties of TDSs and examine polarimetric radar signatures, such as negative ZDR. The LES model incorporates a six degree-of-freedom (6DOF) model for debris trajectories to calculate debris orientation, enabling an assessment of hypotheses of common debris alignment in tornadoes.