Propagation modeling for some horizontally varying tropospheric ducts
Abstract
For propagation assessment in a maritime environment, the assumption of horizontal homogeneity (i.e., invariance of the refractivity structure along the path of propagation) is generally adequate (Hitney et al., 1985). Nevertheless, theoretical methods are available to handle special cases when the assumption fails. For example, horizontal inhomogeneity can in principle be treated by mode conversion methods or by parabolic equation solvers. The theory for a slab mode conversion model is discussed within the context of modified refractive index formalism and applied to several hypothetical laterally inhomogeneous problems including elevated layers as well as shallow evaporative layers. Results of the mode conversion calculations are compared with parabolic equation results generated concurrently by Ko and Burkom (1987). Most of the comparisons, along with the ease of implementation and speed of the parabolic equation calculations relative to the mode conversion analysis, strongly supports the superiority of the parabolic equation method for systems studies involving laterally inhomogeneous tropospheric layering.
 Publication:

In AGARD
 Pub Date:
 September 1989
 Bibcode:
 1989odae.agarR....P
 Keywords:

 Ducts;
 Mathematical Models;
 Parabolic Differential Equations;
 Refractivity;
 Troposphere;
 Wave Propagation;
 Formalism;
 Homogeneity;
 Inhomogeneity;
 Invariance;
 Communications and Radar