A model for quasi-periodic signals with application to rain estimation from microwave link gain

It has been observed that rainfall may be estimated from the attenuation of microwave links. In this paper, we propose a new approach to this problem (for a single microwave link), which is based on a dynamical model of the attenuation without rain. This dry-air model combines local smoothing with quasi-periodicity over 24 hours. Rainfall causes large deviations of the attenuation from this dry-air model, and the rainfall can be estimated from these deviations.