Microwave Modelling of Rain Attenuation Fields using Disdrometer Measurements and Stochastic Methods

Hydro-meteorological and radio-propagation applications can benefit from the capability to model time evolution of raindrop size distribution (RSD). In this respect this work presents a study to simulate synthetic time series of RSDs using a vectorial autoregressive approach and a semi-Markov chain. A large set of disdrometer measurements, acquired in different climatological sites, is analyzed in order to drive the RSD temporal simulator. Climatological differences of RSD data are quantitatively discussed. A spectral technique, based on an iterative adaptive fast-Fourier-transform technique, is also applied to transform the temporal series into rainfall spatial fields. Numerical examples of radar and radio- propagation parameters, such as co-polar reflectiviy and at Ka-band co-polar specific attenuation, are discussed by employing the rainfall space-time RSD simulator coupled with a raindrop scattering model valid for oblate raindrop ensembles. (5 pages)