The affection on radio propagation of attenuation index in troposphere over Wuhan

Transmitting characteristics of radio wave are determined by the medium in space. All of the Earth-space transmitting is influenced by the unionized atmosphere (especially troposphere) for its large density, high humidity, violently changed temperature and humidity, which can be seen from attenuation index. By analyzing the radiosonde data from Wuhan (30.5°N, 114.4°E) weather bureau, we find out the temporal variation of the tropospheric attenuation index. The attenuation index decreases fast with altitude increasing, and the attenuation index of oxygen reaches its maximum value and minimum value in summer and winter, separately, showing a inverse trend of that of water. The attenuation index of oxygen is bigger in the morning than in the evening, which is different with that of water, either. A typical case for intensive attenuation disturbance and the yearly variation of attenuation for weak attenuation frequency at special altitude are discussed to show the impaction of attenuation on radio propagation.