RePLaT-Chaos

RePLaT-Chaos is an application for simulating the global-scale atmospheric spreading of pollutant clouds. The pollutant clouds consist of aerosol particles or gas particles. RePLaT-Chaos is also a suitable tool for studying the so-called chaotic features of the advection. The application is a simpler version of the previously developed RePLaT (Real Particle Lagrangian Trajectory) model.

In three-dimensional flows, as it is the case in the atmosphere, the advection of pollutants is chaotic. The advection dynamics of pollutants shows typical characteristics of the chaos, such as sensitivity to the initial conditions (the trajectories of initially nearby particles diverge within short time), irregular motion, and complex but regular (fractal) structures. It can be easily observed in the RePLaT-Chaos simulations that pollutant clouds do not disperse in the atmosphere like dye blobs on clothes, rather an initially compact pollutant cloud becomes soon strongly stretched, its length grows rapidly, while becoming filamentary, tortuous and folded. The application can also calculate two quantities which describe the chaoticity of the advection. The stretching rate (topological entropy) characterizes the rate of the exponential stretching of pollutant clouds, while the escape rate quantifies the deposition rate of particles falling out from the atmosphere to the surface.

In the full version each simulation parameter can be changed. The student version includes more animation and explanation for the observable phenomena.