A semi-empirical method of rain attenuation prediction

A randomo distribution model has been developed to predict temperate and tropical climate rain attenuation from the correlation of precipitation region size with rain climate region. Point rain rate equiprobability values are established without any assumptions on the distribution function of point rain rates. The effect of limited size of precipitation region on prediction is accounted for by the introduction of a partial-path rainfall correction into the model. Experimental data obtained from three raingauges placed on a 2.5 km path in XiinXiang, Henan, China covered the usable frequency range from 7-40 GHz. The model provides better accuracy than the recommended CCIR method for both terrestrial and earth-space paths at small percentages of time, particularly for tropical rain climate regions. Certain conditions are specified for the long term distribution of tropical rain climate region point rain rates.