Influence of anisotropy of marine turbulence on the variance of optical wave AOA fluctuations.

Abstract

The optical wave angle of arrival (AOA) fluctuations in marine turbulence severely degrade long-range imaging quality by introducing image distortion. Theoretical investigations of optical wave AOA fluctuations are critical to improve the performances of long-range imaging systems in marine turbulence conditions. In this work, analytic expressions for the variance of optical plane and spherical wave AOA fluctuations in anisotropic marine turbulence will be derived. Compared with the previous models that focus on the isotropic and Kolmogorov properties of marine turbulence, both the anisotropy and non-Kolmogorov features of marine turbulence are considered. The anisotropic factor, general spectral power law instead of constant value of 11/3, finite turbulence inner and outer scales, and variable wavelength are included in the models developed in this work. Also, comparative analyses are performed for the models derived separately in marine and terrestrial anisotropic turbulence conditions. It turns out the anisotropy of turbulence cells degrades the effects of marine turbulence on the optical wave AOA fluctuations. Also, the marine atmosphere humidity fluctuations increase the impacts of anisotropic marine turbulence on the final derived models.