Averaging Aspects in Short Term Forecasts of Tropospheric Attenuation

At cruising altitude airborne satellite connectivity is unproblematic since no clouds or precipitation occur above the aircraft. The critical portions of the flight are directly after take-off and before landing, where especially rain can severely influence microwave signals. In short term forecasts of precipitation high rain peaks may not be resolved due to the inherent averaging of forecasts. Here we present an empirical study to illuminate the deviations of forecasted data from high resolution rain rate measurements of a distrometer situated in Graz, Austria. The forecasts are simulated by averaging over the measured data to create ideal conditions. The focus lies on the averaging effects only; the forecast algorithm itself is not examined. The integration time is adapted to reflect available forecast data in Austria. In addition, potential limits for the deviations between high resolution time series of rain rates and average values of whole periods are discussed.