Propagation modelling over irregular terrain using the split-step parabolic equation method

The author outlines the adaptation to irregular terrain of an existing computer model used for electromagnetic propagation around a smooth spherical earth. The parabolic equation method (PE) has become an accepted and powerful tool in the analysis of electromagnetic propagation over the sea during ducting events. A useful extension of this model would by the ability to include the coastal strip in this analysis by extending the model´s applicability to include irregular terrain. The author explains how the split-step PE model developed for single obstacles is applied to irregular terrestrial path profiles. Finally, as a demonstration of the model over continuous terrain, a typical coastal strip profile from the Bristol Channel area has been modelled and the result is presented