大气折射率起伏对雷达波的散射

研究大气折射率起伏对雷达波的散射时,得到的主要結果有以下两点: 1.在适当的大气条件下,折射率起伏构成的后向散射波能够超出一般雷达的灵敏度之上,它的量級正好和雷达观測到的气象“仙波”相同.根据这一結果和其他事实,作者认为起伏的后向散射可能是形成气象“仙波”的重要机制。 2.推导了表示雷达波在折射率有起伏的介貭中传播时,强度随距离变化的方程式,結果发現:一般情况下,散射效应不致引起波的强度的显著变化.但是,当大气折射率起伏的尺度长較小、輻度較大、并且雷达波瓣較窄时,散射效应会引起波瓣的加寬。

ON THE SCATTERING OF RADAR-WAVE BY FLUNCTUATIONS OF ATMOSPHERIC REFRACTIVITY

Scattering of radar-wave by flunctuations of atmospheric refractivity is studied in this paper. The main results are as follows: In case of intensive atmospheric refractivity flunctuations, the power of back-scattered. radiation due to the refractivity flunctuations may exceed the minimum detectable power of radar, and is of same order of magnitude as the meteorological "angel" wave. With other evidences, it is hence suggested that the scattering by refractivity flunctuations may be an important mechanism in the formation of meteorological "angel" wave. 2. An equation is derived to express the wave magnitude as a function of the distance propagated in the medium with refractivity flunctuations. It is found that the scattering effect does not affect the wave magnitude significantly in general, but it may cause the wave-width to spread when the scale length of refractivity as well as the wave-width of radar are quite small.