Estimation of optical turbulence structure in the unstable surface boundary

Walter B. Miller; Henry Rachele

doi:10.1117/12.21865

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1 September 1990 Estimation of optical turbulence structure in the unstable surface boundary

Walter B. Miller, Henry Rachele

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Proceedings Volume 1312, Propagation Engineering: Third in a Series; (1990) https://doi.org/10.1117/12.21865
Event: 1990 Technical Symposium on Optics, Electro-Optics, and Sensors, 1990, Orlando, FL, United States

Abstract

In the atmospheric surface boundary layer, traditional optical turbulence models fail to provide environment-specific information. Moreover, new forms proposed for the turbulence spectrum depend on the turbulent inner and outer scales, as well as the refractive index structure parameter profile. Use of these turbulence spectrums to estimate propagation statistics for general linear propagation paths requires knowledge of all three profiles. These profiles exhibit a definite, interrelated vertical structure in the atmospheric surface boundary. Evidence suggests the actual turbulence spectrum should exhibit a "bump" in the region near frequencies associated with the inner scale. Therefore, propagation statistics are likely more sensitive to inner scale than previously expected. Consequently, reasonable estimates of inner scale become necessary to ensure accuracy of models predicting optical turbulence effects on propagation. The optical turbulence model contained in the Electro-Optical Systems Atmospheric Effects Library module IMTURB (imaging through optical turbulence) has been extended to calculate the profile for inner scale. Obukhov similarity is used to predict surface fluxes and gradients, and the Kolmogorov principle of universal equilibrium is employed to estimate dissipation. From dissipation profiles, consistent profiles of turbulent inner and outer scale are predicted, as well as the refractive index structure parameter profile. This comprehensive description of optical turbulence structure, when used with one of the new forms for the turbulence spectrum, will result in more realistic linear propagation statistics for the dry unstable surface boundary.

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Walter B. Miller and Henry Rachele "Estimation of optical turbulence structure in the unstable surface boundary", Proc. SPIE 1312, Propagation Engineering: Third in a Series, (1 September 1990); https://doi.org/10.1117/12.21865

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