Effect of refractive dispersion on the trichromatic correlation of irradiances for atmospheric scintillation

Formulations of the trichromatic correlation of scintillating irradiance are corrected by introducing the cospectrum of the two different refractive indices in place of the refractive index power spectrum. Receiver aperture averaging is included in the formulation. The effect of dispersion on the bichromatic correlation coefficient is studied and quantified for four specific experimental cases. Dispersion of the water vapor refractive index between wavelengths in the visible and 10 microm window is of particular significance in this study. In most cases, the effect of dispersion on the bichromatic correlation coefficient is much less than on the ratio of monochromatic irradiance correlations, and is negligible for practical considerations. The exception is the case of such strong humidity fluctuations that they (as opposed to temperature fluctuations) cause most of the scintillation of the midinfrared radiation.