Tornadoes, Thomson, and turbulence: an analogous perspective on tornadogenesis and coherent structure in the atmosphere

While there have been intermittent contributions to the literature invoking analogies between the equations of electromagnetism (EM) and hydrodynamics (HD) over the past century, the presentation and application of such analogies have been limited in both scope and consistency. In this presentation, we invoke “analogous thinking” in the context of tornadogenesis in particular, and atmospheric coherent structure in general. We first present a case for a different perspective, based on the Lamb vector and its divergence, in diagnosing coherent structure. We then present a brief review of some of the more recent work in establishment of EM-HD analogies. Using these various perspectives, we compile a consistent, practical list of isomorphic variables for diagnostic use, aimed specifically toward atmospheric applications. After developing logical extensions to the list of variables, we apply these in the context of tornadogenic numerical simulations. By analyzing spatio-temporal correlations of a new variable, called vortex ‘susceptibility', with vortical evolution in the simulations, our extensions to the framework provide a basis for a physical explanation of vorticity preservation, or ‘recycling', in a tornadic environment.