微波斜径传播对流层大气湍流结构常数模型

Structure Constant Model of Troposphere Atmosphere Turbulence on Microwave Slant-Paths

在微波遥感和卫星通信领域内 ,对流层湍流大气引起的信号闪烁现象的研究是至关重要的一个问题。引起接收信号闪烁的大气折射率起伏一般由大气结构常数Cn2 来度量。根据ITU R光波波段的Cn2 模型及ITU R幅度闪烁标准偏差σχ 的经验模型讨论了在微波波段影响Cn2 的主要因素 ;建立了微波波段的Cn2 模型。其优点是考虑了大气温度和湿度随高度的变化。根据湍流的幅度闪烁理论 ,在频率分别为 12GHz,2 0GHz和 30GHz时 ,用该Cn2 模型计算了σχ,并与ITU R和Ortgies模型的预测结果进行了比较 ,结果表明一致性较好 ,说明该Cn2 模型是实用的。

In the fields of microwave remote sensing and satellite communication, it is an important problem for the investigation of the received signal scintillation due to troposphere turbulence. The received signal scintillation induced by refractive index fluctuation is generally measured with atmosphere structure constant C n 2. In this paper, the main factors that affect on the C n 2 are discussed in microwave band. A model of C n 2 is presented at microwave band based on ITU-R C n 2 model for optical wave and ITU-R amplitude scintillation σ χ model. It has been considered that the temperature and relative humidity varied with height. The comparisons of the values calculated by the C n 2 model with ITU-R and Ortgies model prediction results are given. It is shown that the calculation values agree almost with the prediction results. It is also shown that the C n 2 model is practical.