Radar Simulator to Aid Characterization of Scattering Debris Particles in Tornadoes

A team of researchers from University of Oklahoma's Advanced Radar Research Center have jointly developed the world’s first numerical polarimetric radar simulator. The simulator will be used to study and characterize scattering mechanisms of debris particles in tornadoes.

Scattering debris from a tornado is known to cause most of the damages. A tornado’s debris characteristics are generally poorly understood even though the upgradation of the radar network to a dual polarimetric radar offers potentially valuable capabilities for improving tornado warnings and now-casting. According to the team these results are important for operational weather forecasters and emergency managers as an improved understanding of what weather radars tell about tornado debris can help provide more accurate tornado warnings, and quickly direct emergency personnel to affected areas.

Numerous controlled anechoic chamber measurements of tornadic debris were conducted at the Radar Innovations Laboratory on the OU Research Campus to determine the scattering characteristics of several debris types - leaves, shingles and boards. The simulator was developed by the team of Robert Palmer, D.J. Bodine, B.L. Cheong, C.J. Fulton, S.M. Torres, ARCC team, and the OU Schools of Electrical and Computer Engineering and Meteorology, to provide comparisons for actual polarimetric radar measurements.

There have been many unanswered questions until now, related to tornado debris scattering, such as knowing how the size, concentration and shape of different debris types affect polarimetric variables. How the radar identifies the debris is equally as important. Orientation of debris makes a difference as well as how the debris falls through the atmosphere. The recent study will now help in understanding debris scattering characteristics and subsequently aid in the discovery of the relationship between debris characteristics, such as lofting and centrifuging, with tornado dynamics.

OU team members were responsible for various aspects of this study. Coordination of damage surveys and collection of debris samples were led by D.J. Bodine. Field experiments were designed by team members in collaboration with Howard Bluestein from OU School of Meteorology. The electromagnetic simulations and anechoic chamber experiments were led by C.J. Fulton. The signal processing algorithms were developed by S.M. Torres and his team. B.L. Cheong was in the lead of the simulation development team.

The study, “SimRadar: A Polarimetric Radar Time-Series Simulator for Tornadic Debris Studies,” will be published in the May issue of the Institute of Electrical and Electronics Engineers Transactions on Geoscience and Remote Sensing. The work is supported by the National Science Foundation.