水平气流中微波折射率结构常数建模

Modeling atmospheric refractive index structure constant of microwave in horizontal airflow

电磁波在大气中传输时会受到大气湍流的影响,湍流的强弱可以用折射率结构常数C2n来表示.在2.4 GHz的微波环境下,重点研究了微波段空气中水汽压对大气折射率结构常数的影响.温湿度结构常数的计算选择湍流动能(turbulence kinetic energy,TKE)闭合方案,由耗散率方法求得,修正了干燥空气的归一化公式,在水平气流环境中构建了微波折射率结构常数的模型.结合隧道环境中实测的气象参数,采用该模型分析实验时的微波折射率结构常数,得到在2.4 GHz的微波环境下,湿度对折射率结构常数的贡献大于温度.

Electromagnetic waves propagating in the atmosphere are influenced by atmospheric turbulence. The structure constant of atmospheric refractive index are generally used to describe turbulence intensity. This paper studies effects of the water vapor pressure in air on atmospheric refractive index in the 2.4 GHz microwave band. A turbulence kinetic energy （TKE） closure scheme is chosen and the structure constant of temperate and humidity is calculated with a turbulent dissipation rate. Then the normalization formulas for dry air are revised at the microwave frequency of 2.4 GHz, and a model of the structure constant of atmospheric refractive index is built in the microwave band in a horizontal airflow. In addition, the model is applied to calculate the atmospheric refractive index structure constant of microwave based on the meteorological parameter actually measured in a tunnel environment. The result indicates that humidity has a more obvious effect on refractive index structure constant in the 2.4 GHz microwave band than temperature.