Implementation of Tornadic Debris Signature Guidance Using Polarimetric WSR-88D Data

The additional products provided by a polarimetric weather radar allow one to identify better the presence of debris lofted by a tornado. A polarimetric Tornado Debris Signature (TDS) has been identified in previous observations of tornadic storms and, more recently, in numerical simulations. In this study, an automated TDS detection algorithm under development at the National Severe Storms Laboratory is described. The membership functions necessary for a fuzzy-logic-based algorithm are determined from previously-published studies of TDS data and a geographically diverse and vast verification dataset consisting of TDS events identified in WSR88D data between 2010 and 2013. Several TDS "swaths" are compared with ground-based damage survey results, and the difficulties involved with automated TDS detection (e.g., the lack of a TDS caused by a dearth of debris lofted to the height of the radar beam by weak or distant tornadoes) are discussed.8 on 7-11-2014-->