Optical Turbulence Effects on Ground to Satellite Microwave Refractivity

摘要

Due to the increased use of laser and microwave ground-to - satellite communications the need for reliable optical turbulence information is growing. Optical turbulence information is important because it describes an atmospheric effect that can degrade the performance of electromagnetic systems and sensors e.g. free-space optical and microwave communications and infrared imaging. A quantitative measure of the intensity of optical turbulence is the refractive index structure parameter, Cn2. A critical analysis of selected past research on optical turbulence in diverse microclimate environments indicates that the magnitude of Cn2 generally increases with wavelength. This is because the overall contribution to Cn2 due to moisture (i.e. humidity gradient) effects significantly increasing wavelength. As an example, the values for near- millimeter wave Cn2 can be larger by an order of magnitude or more than ones in the infrared, which are mainly dependent on temperature structure. Hence, this paper provides a brief review of temperature and humidity effects on microwave Cn2, to include key computational algorithms and comprehensive reference citations. We anticipate that this work will be useful and informative to those interested in the design and performance of earth and space communication systems.