Two-dimension visualization of rain cell structures


  • Julius Goldhirsh


A methodology is described for the simulation of two-dimensional rain rate fields based on a formulation derived from radar measurements of other investigators and modeled point rain rate distributions. This simulation enables a determination of typical radar clutter maps of rain backscatter and estimates of terrestrial path attenuation as a function of distance and azimuth. Rain rate fields are derived for three diverse climatological regions, and a step-by-step methodology is presented for determining them. Parameters are tabulated, enabling the determination of rain rate fields for any of the 15 International Telecommunication Union-Radio Communication rain rate zones. Examples giving typical path attenuation at 10 GHz versus distance profiles and 3-GHz radar backscatter profiles are calculated. A modified formulation that predicts cumulative slant path fade distributions for Earth-satellite scenarios using many of the elements of the simulation technique is reviewed. As a partial validation of the described rain rate field simulation technique, the cumulative fade distribution was calculated at 28.56 GHz and compared to the derived distribution from a previous 3-year measurement program involving the COMSTAR satellite. The calculated and measured levels were observed to give close agreement over the attenuation range from 3 to 25 dB, resulting in a root-mean-square deviation smaller than l dB and a standard error of approximately 10%.