Ground level refractivity and scintillation in space-earth links.

Slant-path scintillations are investigated by means of measurements at microwaves made in Rome and Beijing using the SIRIO satellite. Comparison with ground level temperature, humidity, and radio refractivity is performed, and close similarity is found with daily and seasonal behavior of the scintillations. An explanation of this similarity is proposed that leads to simple empirical relationships between the scintillation intensity and the ground level quantities. The intensity of scintillations has been also estimated using meteorological radiosonde measurements, and satisfactory agreement is found with simultaneous direct scintillation measurements.