ESTIMATING RISK FOR EARTH-SATELLITE ATTENUATION PREDICTION

Annual cumulative distributions of attenuation measurements and of rai n-rate measurements were obtained from several locations in Europe and the United States. They were analyzed to estimate the year-to-year va riability to be associated with a prediction of the expected cumulativ e distribution. Two models were constructed to estimate variability, a n ad hoc model that summarized a number of observations when compared to model predictions and a probabilistic model that applied the ideas of order statistics to the prediction problem when the number of indep endent attenuation or rain-rate events in a sample year could be estim ated. Based on these models, the statistical uncertainty in a model pr ediction may be estimated. The estimation procedure also provides an a nswer to the question of the number of years of observation needed to provide an estimate of the empirical distribution with a specified sta tistical uncertainty.