Modelling of electromagnetic transmission through rain fields based on drop-scale scattering

This article presents extensions of a numerical technique to model electromagnetic propagation through rain. Embedded in the Helmholtz Virtual Institute 'Regional Precipitation Observation by Cellular Network Microwave Attenuation and Application to Water Resources Management' (PROCEMA) the method serves as theoretical basis for a novel method to measure ground-based precipitation. Indeed Messer et al. [1] propose to utilize attenuation of commercial point-to-point links for obtaining precipitation information. This theoretical framework models a rain field and its influence on electromagnetic propagation taking into account drop scale scattering as well as rain drop movement. In the virtual rain model the rain drops populate a volume and scatter the incident electromagnetic wave by each drop individually. A derivation of the attenuation of the incident field by the global rain field extends the original algorithm. Additionally, a table of the scattering coefficients further accelerates numerical computations within the model.