The phenomenon of scintillations in relation to rain attenuation of Ku-band satellite signals has been studied at a tropical location. The standard deviation (σ) of scintillations increases with attenuation up to a value in the range of 6-7 dB, beyond which σ decreases with attenuation. A technique is proposed to obtain some effective values of structure constant (Cn2) of refractive-index variation from the experimental observations of σ and rain rate (R). The value of Cn2 also increases with attenuation up to values in the 6-7-dB range and decreases beyond that value. The eddies in turbulent raining medium grow with rain rate, and consequently with attenuation, causing an increase in the outer scale (LO) of turbulence and thus increasing σ until LO reaches the size of the first Fresnel zone. In a further development, the contribution of LO toward Cn2 decreases, resulting in the decrease of fast fluctuations with rain attenuation.
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机译:在热带地区已经研究了与Ku波段卫星信号的降雨衰减有关的闪烁现象。闪烁的标准偏差(σ)随衰减而增加,直到6-7 dB范围内的值,超过此值,σ随衰减而减小。提出了一种从σ和降雨率(R)的实验观测值获得折射率变化的结构常数(C n sub> 2 sup>)的有效值的技术。 C n sub> 2 sup>的值也随衰减增加而增加,直到6-7 dB范围内的值,然后减小到该值以下。湍流降雨介质中的涡流随降雨率的增长而增长,并因此而衰减,从而导致湍流的外部尺度(L O sub>)增大,从而使σ增大,直到L O sub>达到第一个菲涅耳区的大小。在进一步的发展中,LO对C n sub> 2 sup>的贡献减小,从而导致快速起伏随降雨衰减而减小。
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