Extrapolation of point rain-rate distributions.

The arbitrary definition of when it is raining implies the uncertainty of total raining time, i.e., the ambiguous raining probability P(o) in the log- normal representation of point rain-rate distribution. A numerical experiment has demonstrated that results of extrapolating the point rain-rate distribution to lower and higher rain rates using a log-normal approximation are insensitive to P(o). In light of the scarcity of light rain statistics and the instability of very heavy rain statistics, the proposed extrapolation technique will be practically useful in microwave communication system engineering.