Anomalous propagation and radar coverage through inhomogeneous atmospheres

A method is outlined which enables radar coverage predictions to be made under anomalous propagation conditions. Spatial and temporal changes in the height and strength of refractive layers in the troposphere are known to compromise radar coverage. Refractive layers may create coverage voids by diverting rays and may introduce anomalous clutter and range height errors in radar systems. In this paper, elements of meteorology, atmospheric boundary layer physics, and electromagnetic wave propagation are combined to investigate the effect of inhomogeneous refractive layers on radar coverage. A computer program called EMPE (Electromagnetic Parabolic Equation) has been developed to aid in these investigations. A special feature of EMPE is its ability to deal with inhomogeneous atmospheric changes in both the horizontal and vertical directions. Predictions for anomalous wave behavior have been made for frequencies from 100 MHz to 10 GHz. The results are relevant to a variety of microwave electromagnetic systems such as those used for communications, radar, and aircraft instrument landing.