On the effects of sea roughness on the predictions of pathlosses above sea

In the last few years, a major weakness of modern path loss prediction methods over sea has been thought to be the inadequate treatment of sea roughness in the models. Nevertheless, experimental investigations of the effect of sea roughness on prediction quality are lacking. In this paper, we show prediction errors obtained as a function of wind speed, from which sea roughness can be inferred, using models that neglect surface roughness. Data obtained from trans-horizon propagation links at 3 and 10.5 GHz, setup near the littoral in the Atlantic Ocean and in the Mediterranean, are considered in the analysis. Prediction errors were found to reach a maximum at moderate wind speeds (~10 m/s), and then to decrease with increasing wind speeds. The analysis supports the idea that prediction error increases with growing wave height (sea state) and decreases as the waves break and the conditions homogenize