A method for deriving a time-series of the attenuation on fixed satellite or terrestrial links is described. The method uses meteorological forecast data and radar data and hence permits time coincident derivations for multiple sites that include the spatial correlation properties inherent in weather systems. The success of the technique depends upon insertion of the short interval temporal properties (varying typically over 1 second to 15 minutes) that are statistically independent between stations. The methodology is described, examples of time-series derived at multiple-sites for satellite-Earth links are given, and comparisons with measured time-series are included. More data are required to enable long-term comparisons of cumulative statistics to be made that should lead to an improved quantitative calibration of the system, but an example of a simulated power spectrum is included that illustrates a strong similarity to measured data. The technique has immediate application to simulation of the performance of multimedia satellite (or high-altitude platform) to Earth links and has longer-term significance in terms of realtime operational use.