tropospheric propagation

Electromagnetic-field propagation within the troposphere to achieve long-range communication over hundreds of miles. In the lower part of the earth's atmosphere, electromagnetic energy may be reflected/refracted within and between air masses of different density. The air also produces some scattering of electromagnetic energy. All these effects are known generally as tropospheric propagation. The effects are most pronounced in the vicinity of a weather front. Long-range TV signal reception is the result of tropospheric propagation. Such propagation is usually of short duration and not suitable for reliable signal transmission.