Optical Turbulence Forecasting

Optical Turbulence Forecasting
Author: Edmond M. Dewan
Publisher:
Total Pages: 76
Release: 1980
Genre: Atmospheric turbulence
ISBN:
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This report is a tutorial on the effects of atmospheric turbulence upon systems which rely upon the propagation of LASER beams. In addition to providing a simplified presentation of turbulence theory and optical effects, it describes the state of the art of the new technique of radiosonde estimation of index of refraction fluctuations. Suggestions are given for future research which will help to answer current Air Force needs. The feasibility of some laser systems will depend upon the value of r0, the coherence length (which is related to “C2n” which in turn is related to the degree of turbulence). At present, the statistics of “r0” are inadequate.

Effects of Atmospheric Turbulence on Optical Instrumentation

Effects of Atmospheric Turbulence on Optical Instrumentation
Author: Randolph A. Becker
Publisher:
Total Pages: 17
Release: 1961
Genre:
ISBN:
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The results of research on optical turbulence at White Sands Missile Range are presented. It has been shown that elevating camera stations 33 feet above ground level can yield nearly a threefold increase in optical resolution during periods of atmospheric turbulence. Early research postulated the existence of thermal-induced air-lenses as the cause of optical turbulence effects. Recent research has shown that air-lenses can account for most of the observed effects. The 'prism' concept of turbulence appears to be unnecessary for explaining trubulence -induced image motion. The dependence of the optical effects of turbulence upon exposure time and aperture size is discussed qualitatively. The source of optical turbulence in the atmosphere and a method of measuring the trubulence-generating potential of various terrain surfaces are described on the basis of micrometerology. This research has been limited to an investigation of optical turbulence during the period from sunrise to sunset. However, many of the results apply to the nighttime turbulence encountered by astronomers. (Author).

Imaging Through Turbulence

Imaging Through Turbulence
Author: Michael C. Roggemann
Publisher: CRC Press
Total Pages: 389
Release: 2018-02-06
Genre: Technology & Engineering
ISBN: 1351439308
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Learn how to overcome resolution limitations caused by atmospheric turbulence in Imaging Through Turbulence. This hands-on book thoroughly discusses the nature of turbulence effects on optical imaging systems, techniques used to overcome these effects, performance analysis methods, and representative examples of performance. Neatly pulling together widely scattered material, it covers Fourier and statistical optics, turbulence effects on imaging systems, simulation of turbulence effects and correction techniques, speckle imaging, adaptive optics, and hybrid imaging. Imaging Through Turbulence is written in tutorial style, logically guiding you through these essential topics. It helps you bring down to earth the complexities of coping with turbulence.

Effects of Atmospheric Turbulence on Optical Propagation

Effects of Atmospheric Turbulence on Optical Propagation
Author: R. S. Lawrence
Publisher:
Total Pages: 8
Release: 1984
Genre:
ISBN:
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The optical refractive index of the atmosphere depends on temperature, pressure, and humidity. Naturally occurring variations of these quantities, with scales of a few centimeters and associated with atmospheric turbulence, cause optical scintillation, image distortion, and laser beam broadening. I review the meteorological conditions that influence the occurrence of this optical turbulence, discuss the optical significance of turbulence at various heights in the atmosphere, and point out the differences between these optical effects and the corresponding phenomena at radio wavelengths. While beam broadening increases indefinitely with the strength of optical turbulence, scintillation saturates and eventually decreases with increasing turbulence.

An Investigation of Atmospheric Turbulence by Stellar Observations

An Investigation of Atmospheric Turbulence by Stellar Observations
Author: Jack Lytle Bufton
Publisher:
Total Pages: 188
Release: 1971
Genre: Astrophysics
ISBN:
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This study of the optical effects of atmospheric turbulence concentrates on the stellar observation problem. When an infinite plane wave from an incoherent stellar source is sampled by an earth-based telescope, the resultant stellar image exhibits random fluctuations in intensity, position, and size due to turbulence-induced scattering in the intervening atmosphere. One familiar aspect of this problem is the scintillation of starlight apparent to the naked eye. The central aim is to express optical statistics in terms of refractive-index structure constant which pertains to strength of turbulence along the optical path. Data is presented on stellar and meteorological observations made between fall 1968 and spring 1969 with a 0.152-meter diameter refracting telescope. Data was recorded simultaneously on the three parameters of image intensity, motion, and size. The data is interpreted in terms of the theory and used to estimate strength of turbulence. The central result is a series of profiles for refractive-index structure constant along the vertical path. These are constructed using stellar data to calculate parameters of a model.