2026/07/01 by Kelcy Brunner, Kelcy N. Brunner, Eric Bruning +3
Earth and Planetary Sciences · Physics and Astronomy · Environmental Science · #Meteorological Phenomena and Simulations #Lightning and Electromagnetic Phenomena #Fire effects on ecosystems
paper · doi:10.1175/jas-d-24-0029.1
Abstract Radar variables are commonly used to identify deep convection in thunderstorms. Polarimetric radar provides additional signs of deep convection with columnar regions of increased differential reflectivity ( Z dr ) and specific differential phase ( K dp ). However, the prevalence of polarimetric signals across all trackable storm objects observed by radar is not well understood and is necessary context for understanding the prevalence of polarimetric parameters in deep convection. In this study, we objectively track all thunderstorm objects observed by WSR-88D NEXRAD radar on eight storm days in the southeastern United States. The case days are selected from the Verification of the Origins of Rotation in Tornadoes Experiment-Southeast (VORTEX-SE) and Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaigns and encompass a wide range of storm modes, including quasi-linear convective systems, a storm type for which its hazards are notoriously difficult to forecast. Storms are objectively identified and tracked using the open-source analysis tool Tracking and Object-Based Analysis of Clouds (tobac), and over 2800 tracked cells are identified over the eight case days. The tobac provides a feature mask at every time step of a tracked cell. Within each cell shape, we examine the prevalence of Z dr and K dp columns above the melting level and lightning activity. We find that columns of Z dr are widely prevalent, even in thunderstorms without lightning or any other polarimetric column features, but still meeting the tracking threshold of 30 dB Z . However, intense K dp columns are related to lightning production—columns with lightning are over 2 times stronger than those without lightning. The microphysical development in the storm leading to electrification and polarimetric column observations is also discussed. Significance Statement The purpose of this study is to better understand how prevalent microphysical radar signatures are in the presence of lightning. This is important because thunderstorms electrify via collisions between ice and hydrometeors within the cloud. Cloud electrification is initiated within the mixed-phase region of thunderstorms, where populations of these particles are found in large quantities, and can be observed with polarimetric radar. Our results are a step toward understanding relationships between lightning and what we can observe with radar for all storm types.