Fig. 3.3. Climatological and Heating Effects of the Microwave Power Transmission System in the Lower Atmosphere Variations in the refractive index of the atmosphere and the presence of hydrometeors (droplets, raindrops, hail, ice crystals, etc.) in the atmosphere cause refraction, scattering, and absorption of electromagnetic waves. At 2.45 GHz the refractive index of air at fixed pressure depends mostly on water vapor and temperature. In the presence of convective or turbulent air motions, a spectrum of atmospheric refractivity variations develops which can lead to beam wandering and spreading. The scattering and absorption by hydrometeors depends on their size, shape, number, concentration, and composition. If these properties are specified, atmospheric attenuation and beam spreading can be calculated. Contributions to beam wandering and spreading from the planetary boundary layer, cloud systems, jet stream turbulence, and stratified atmospheric layers must all be considered. These atmospheric effects on electromagnetic propagation contribute to the power beam and pilot beam stability problems. Slowly varying and
RkJQdWJsaXNoZXIy MTU5NjU0Mg==