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Proceedings Paper

Statistical analysis of measurements of atmospheric turbulence in different climates
Author(s): Karin Weiss-Wrana; Leslie Salem Balfour
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Paper Abstract

Atmospheric turbulence may have a strong impact on the imaging quality of long range warning sensors and other electro-optical systems. Major effects are beam broadening, intensity fluctuations (or scintillation) and angle-of- arrival fluctuations. The structure constant of refractive index fluctuations, Cn2, is the parameter most commonly used to describe the strength of atmospheric turbulence. FGAN-FOM measured Cn2 values in two different climates, moderate climate in mid-Europe, Germany and arid climate in Israel. The measurements in arid climate were carried out in cooperation with the EORD (Electro-Optics Research & Development Foundation Ltd.), TECHNION, Haifa, Israel. The measurements were performed with identical laser scintillometers along a horizontal optical path of about 100 m, above grassland in mid-Europe, and above stony ground without vegetation in Israel. The data were collected continuously for a time period of at least one year at a time resolution of 5 minutes. For both climates examples of the diurnal cycle of Cn2 are given. Since Cn2 usually changes as a function of time-of-day and of season its influence on electro-optical systems can only be expressed in a statistical way. Therefore the cumulative frequencies of occurrence of Cn2 were calculated for a time period of one month for both climates. These results were used to calculate the corresponding turbulence modulation transfer function (MTF) and point spread function (PSF) for a typical IR sensor with a Cadmium Mercury Telluride detector (CMT) and a UV sensor.

Paper Details

Date Published: 29 January 2002
PDF: 9 pages
Proc. SPIE 4538, Optics in Atmospheric Propagation and Adaptive Systems IV, (29 January 2002); doi: 10.1117/12.454395
Show Author Affiliations
Karin Weiss-Wrana, FGAN-FOM (Germany)
Leslie Salem Balfour, Technion-Israel Institute of Technology (Israel)


Published in SPIE Proceedings Vol. 4538:
Optics in Atmospheric Propagation and Adaptive Systems IV
Anton Kohnle; John D. Gonglewski; Thomas J. Schmugge, Editor(s)

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