Abstract

A new analytical model of the spatial power spectrum of temperature fluctuations in the atmospheric boundary layer, showing the characteristic bump just prior to the dissipation ranges, has recently been developed as a modification of the standard Tatarski model.¹ This new model is based on random fluctuations in the average dissipation rates ε_r and χ_r and the correlation coefficient ρ between ϵ_r and χ_r, using a bivariate gamma distribution for the joint density function. In optical wave propagation problems the refractive index fluctuations are caused almost exclusively by temperature fluctuations. Hence, the spectra of temperature and refractivity are generally taken to have the same functional form. This new analytical model for the refractive index spectrum is used to derive analytical expressions for the variance of log intensity of both plane waves and spherical waves propagating through homogeneous turbulence as a function of the Fresnel zone size, the covariance function of log amplitude for a plane wave, the structure function of the phase associated with a plane wave, and the phase coherence length for plane waves.

© 1989 Optical Society of America