Sodar echoes and line of sight microwave propagation

The thermal structures of the boundary layer are investigated with respect to the simultaneous existence of the microwave propagation features for a line of sight path with a receiving end at Delhi (India). The microwave communication characteristics are found to have a correspondence with the sodar structures of the stable and unstable boundary layer, the stable boundary layer being responsible for most of the observed microwave fading characteristics. A correlation of the nature of the sodar structures is established with the magnitude of the initial refractivity gradient present. A ray-tracing program is developed for determining the trajectories for the line of sight link under investigation, and model calculations of the received field strength for some selected values of the initial refractivity gradient are presented.