Statistics of Optical and Quasi-Optical Line-of-Sight Propagation through the Stably Stratified, Optically Clear Atmosphere
Abstract
The purpose of this project was to develop, refine, and validate physics-based models of the spatiotemporal statistics of clear-air refractive-index fluctuations and to apply them to canonical, line-of-sight propagation scenarios and imaging-system performance metrics. In our approach, we combined theoretical analysis, field data analysis (both in-situ and remote), and computer simulations (both fluid mechanics and electromagnetics). Our activities focused on the following research topics: non-Kolmogorov turbulence and inner-scale effects; anisotropy and outer-scale effects; non-Gaussianity of turbulent refractive-index and phase increments; and the relative merits of the geometrical-optics method, the Rytov method, and the phase-screen method for modeling optical propagation through the turbulent atmosphere. Our main findings can be summarized as follows: 1) At small scales, the Obukhov-Corrsin similarity theory is robust and reliable, which questions the usefulness and need of "non-Kolmogorov turbulence'' models, at least for turbulence near the ground; 2) the Hill-Frehlich model predicts inner-scale effects reliably; 3) the probability density of turbulent refractive index and phase increments tend to be Laplacian and not Gaussian; 4) in the strong-fluctuation regime, the geometrical-optics method (ray-tracing) is more reliable than the Rytov method.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 07, 2024
- Accession Number
- AD1230282
Entities
People
- Andreas Muschinski
Organizations
- Northwest Research Associates