Long term statistics of precipitation rate return periods in the context of microwave communications

Using a 49 year point rainfall rate data bank the authors summarise the analysis and statistical modelling of the interval of time between exceedances of rain thresholds R. The study distinguishes between successive exceedances occurring within the same rain event (intra exceedances I_a), and those occurring at different rain events (inter exceedances I_e). The global study of both return periods or intervals I_i is also presented. The study is applied to a 49 year point rain rate data bank. It is found that the annual inter and intra intervals are well modelled by log normal distributions, and each set clusters to a single distribution when the intervals are normalized to their annual averages I¯_a, I¯_e