Review of Operational Applications of Polarimetric Tornado Debris Signatures

In the late 1990s and early 2000s, polarimetric radar signatures of lofted tornado debris were noted for the first time during central Oklahoma tornado outbreaks. These signatures, called polarimetric tornado debris signatures (TDSs), have been increasingly studied over the past decade with the operational implementation of dual-polarization on the nationwide radar network. In this review, we conduct a synthesis of TDS research since the early 2000s to document operational applications and discuss findings from high-resolution research radar studies that more deeply explore TDS structure at fine spatial and temporal scales. Significant efforts have been devoted to studying how TDSs can be used to remotely detect tornadoes and characterize tornado damage severity. So, the strengths and weaknesses of these TDS applications will be discussed. For example, several studies have investigated the relationship between TDS height and near real-time damage severity, and their findings form the basis of operational recommendations for warning statements based on TDS height. Mobile radar research and numerical simulations have also shown that TDSs can be related to characteristics of three-dimensional winds of tornadoes and their parent storms. This research review will use examples from 2019 tornadoes in the central Plains and Southeast United States to illustrate these different TDS applications. The study will conclude with summarized recommendations for future research, including suggestions for studies that explore the benefits of using a future operational phased array radar network to improve tornado detection and characterize three-dimensional changes in debris (e.g., TDS height or volume).