Assessment of model-based scintillation variance prediction on long-term basis using Italsat satellite measurements

The objective of this paper is to assess the accuracy of model-based statistical methods for predicting clear-air scintillation amplitude variance from ground-based meteorological measurements on long term basis. Six model-based estimation methods are considered and discussed, two of them including also the use of vertically integrated water vapour content as a predictor. They are derived from synthetic data, obtained by applying an electromagnetic model to a large historical radiosounding dataset in order to simulate the received scintillation power at microwave and millimeter-wave. The empirical methods of ITU-R, Karasawa, and Ortgies are also considered for comparison. The long-term predictions derived from each method are compared with measurements from the Italsat satellite beacons at 18)7, 39)6, and 49)5 GHz, acquired during 1995 at Spino d'Adda (Milan, Italy) site. The method intercomparison is carried out by checking the assumed best-"tting probability density function for the log-amplitude #uctuation variance and by applying the considered methods to the available ground-based meteorological measurements. Statistical results in terms of bias, root mean square value and skewness of the percentage error are discussed in order to understand the potential and the limits of each model-based prediction method within this case study.