Studying Supercell Storms with a Lagrangian Particle Dispersion Model

Because of the threat they represent to society through damaging winds, hail and, sometimes, tornadoes, supercells are atmospheric phenomena that deserve great attention. Although in the past few decades much has been done to study their dynamics, there remain many aspects of supercell storms, particularly their interaction with the surrounding environment, that are yet to be fully understood. Here, we present a novel approach based on a Lagrangian particle dispersion model and show how it can be used to identify and track different components of a supercell—such as the updraft, the rear-flank downdraft, the forward-flank downdraft, and their associated cold pools—as they evolve in time. As an application of this technique, we focus on the rear-flank downdraft, which has been suggested to be closely linked to tornadogenesis, and discuss how the Lagrangian tracking can be used to study fundamental properties of the downdraft such as its initial height and its driving mechanism. Finally, we discuss how the intrusion of dry layers in the mid-troposphere impacts the dynamics of the rear-flank downdraft.