Analog Computing Techniques Applied to Atmospheric Diffusion: Continuous Point Source

Abstract

The analog computer has been used to obtain solutions to the diffusion equation for the case of a continuous point source aloft. The basic model used is that of a source located between an inversion and the ground where the wind speed and eddy diffusivity are constant over the diffusing region. Solutions were also obtained with several special features added to the basic model: representation of the eddy diffusivity as a function of distance downstream; presence of wind direction shear in the diffusing layers; and the presence of large-scale eddies which cause the meandering of the plume. The solutions are presented as deviations from the reference solution, that solution derived from the basic model, to show graphically the effects of each parameter change.