The power spectrum of water optical turbulence is shown to vary with its average temperature ⟨ T ⟩ and average salinity concentration ⟨ S ⟩ , as well as with light wavelength λ . This study explores such variations for ⟨ T ⟩ ∈ [ 0 ∘ C , 30 ∘ C ] , ⟨ S ⟩ ∈ [ 0 p p t , 40 p p t ] covering most of the possible natural water conditions within the Earth’s boundary layer and for visible electromagnetic spectrum, λ ∈ [ 400 n m , 700 n m ] . For illustration of the effects of these parameters on propagating light, we apply the developed power spectrum model for estimation of the scintillation index of a plane wave (the Rytov variance) and the threshold between weak and strong turbulence regimes.

Optical turbulence occurring in the oceanic waters may be detrimental for light beams used in the short-link communication and sensing systems, and, in particular, in underwater LIDARs. We develop a theory capable of predicting the passage of light beams through the bi-static LIDAR systems, for a wide variety of optical waves, including partially coherent and partially polarized, and for a wide family of targets. Our theoretical framework is based on the Huygens-Fresnel integral adopted to random media and optical systems described by the 4 × 4 ABCD matrices. The treatment of oceanic turbulence relies on the recently introduced power spectrum model of the fluctuating refractive-index [Opt. Express 27, 27807 (2019)] capable of accounting for different average temperatures of water. We first analyze the evolution of the second-order beam statistics such as the spectral density and the degree of coherence of the beam on its single pass propagation and then incorporate this knowledge into the analysis of the bi-static LIDAR returns.inverse problem of finding the parameters of the target embedded in the turbulent medium, from comparison of the incident and the returned waves statistics, has also been tackled for the atmospheric propagation setting [7], [8] and can also be readily adjusted for oceanic propagation problems.