Radar Cross Section Analysis of Tornadic Debris

Abstract

Weather radar is a powerful tool for detecting hazardous weather that may impact citizens. Among these dangerous weather phenomena, tornadoes have a high potential for destruction of property and loss of life due to its rapid formation. It has been observed that a tornado may produce a Tornadic Debris Signature (TDS) when producing heavy damage. To get a better understanding of the TDS, a tornado simulator was created by the Radar Innovations Laboratory where polarimetric variables are simulated by simulating a tornado with hydrometeors and debris and simulating a radar beam scanning said tornado. Scattering by hydrometeors is well known but not for debris as it is random in orientation and shape. To obtain accurate polarimetric products, accurate scattering from the debris is needed.

In order to provide the simulator with accurate scattering from debris, the Radar Cross Section (RCS) from simple objects such as wooden boards and a leaf are simulated using electromagnetic solvers. To validate the simulations, measurements of the simulated debris are taken in an anechoic chamber and compared.

The radar simulator does not take multiple scattering into effect which may impact the results of the polarimetric products. To explore the possibility of needing multiple scattering in the tornado simulator, the multiple scattering by small cylinders and plates is analyzed by using closed analytical solutions by using reaction and reciprocity theorem on the cylinders and Physical Optics (PO) for the plates.