Emulating Polarimetric Radar Signals from Tornadic Debris Using a Radar-Cross-Section Library

In an effort to investigate scattering characteristics of debris particles in tornadoes, a numerical polarimetric radar emulator was developed. Regions of negative differential reflectivity have commonly been observed but are still yet to be explained physically. There are hypotheses that suggest common debris alignment and/or dominant scattering from objects with high radar-cross-section (RCS) values, but they are extremely challenging to verify due to the danger within tornadoes. It is, however, possible to numerically construct the scenes through representative simulation to verify the plausible causes. This serves as our primary motivation to develop the radar emulator. The novel aspects of this work are the realistic trajectory derivation, which is based on physical air-drag model, and the representative diversity of RCS contributions from each debris particle, developed through a realistic polarimetric RCS modeling and anechoic chamber measurements.