Saturation of Irradiance Fluctuations Due to Turbulent Atmosphere

Abstract

Expressions for the variance and other probability moments of strongly fluctuating irradiance of light after propagation through turbulent atmosphere are developed from a high-frequency approximation of the solution of the scalar wave equation. These expressions imply a Rayleigh distribution of the irradiance in the limit of strong turbulence and/or long propagation paths. The theory provides a good fit to Gracheva and Gurvich’s data (corrected for a processing error) and to the more dispersed recent data of Gracheva. It is argued that existing evidence for a log-normal distribution cannot reject a Rayleigh distribution whereas the assumption of log-normal distribution has implications conflicting with theory and/or experiment.