Optical and millimetre wave pulse propagation through fog and rain layers

Pulse propagation in random media is studied by solving the two-frequency radiative transfer equation and transforming the solution into the time domain via Fourier transforms. We briefly review several known techniques of solving the radiative transfer equation and describe a simple and effective finite element method which allows for the investigation of pulse propagation through highly anisotropic media. Specifically, pulse delay and broadening are calculated by solving the radiative transfer equation with empirically determined coefficients for fog and rain layers. In addition, first-order multiple scattering and diffusion approximations are compared to the solutions of the radiative transfer equation, and are found to be useful depending on the values of the single-scattering albedo, optical depth and asymmetry parameter