1-min rain rate statistics predictions from 1-hour rain rate statistics measurements

At high frequencies rain fade is the most important limitation to the propagation of radio waves and big efforts have been devoted by researchers to the prediction of attenuation statistics. All the available prediction models of attenuation cumulative distribution functions (CDFs) use as basic input the long-term point rain rate CDF with short (1-min) integration time P(R)1 as the descriptor of the local meteorological situation. Unfortunately these statistics are not available worldwide; rather data with longer integration time (i.e. 1-hour averaged rain rate cumulative distributions P(R)60) are widely retrievable, being the standard output of meteorological rain gauge networks. It is therefore worthwhile any general procedure able to recover P(R)1 from the ones with longer time integration. Here a new method applicable worldwide, based on the EXCELL rain cell model, is presented; it generates the scaling factors between P(R)60 and P(R)1 as a function of the probability level.