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Proceedings Paper

Experimental data on near-surface refraction effects at optical wavelengths
Author(s): Denis Dion; J. Luc Forand; Georges R. Fournier; Paul W. Pace
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Paper Abstract

The exponentially varying atmospheric density near the water surface can bend the radiation path and potentially affect optical detection and tracking by varying the maximum inter-vision range (MIVR) by causing a positioning error and producing mirages. Using a marine boundary-layer model in conjunction with ray-tracing, quantitative analysis of these effects as a function of meteorological conditions can be achieved and predictions on the nature and magnitude of the induced phenomena can be made. This simple form of analysis produces effects of significant magnitude depending on the conditions. However, the literature reports very few instances of these effects and the few data published on the subject lack the necessary information to relate the phenomena to the prevailing weather conditions. An experiment was conducted over the Ottawa River in the fall of 1991 to verify the occurrence, persistence, and magnitude of these refraction-induced phenomena and initiate the validation of our modelling approach. Both shortened and extended MIVRs as well as mirages were observed and the measurements made were in good agreement with the model predictions. Sample images taken under sub- and super-refraction conditions are presented.

Paper Details

Date Published: 22 December 1992
PDF: 7 pages
Proc. SPIE 1749, Optics of the Air-Sea Interface: Theory and Measurement, (22 December 1992); doi: 10.1117/12.138842
Show Author Affiliations
Denis Dion, Defence Research Establishment Valcartier (Canada)
J. Luc Forand, Defence Research Establishment Valcartier (Canada)
Georges R. Fournier, Defence Research Establishment Valcartier (Canada)
Paul W. Pace, Defence Research Establishment Valcartier (Canada)

Published in SPIE Proceedings Vol. 1749:
Optics of the Air-Sea Interface: Theory and Measurement
Leland Estep, Editor(s)

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