Paper
11 November 2004 Measurements of IR and visual propagation in the marine boundary layer
Lars Trygve Heen, Eirik Blix Madsen, Oddvar Selnes
Author Affiliations +
Abstract
Two field trials have been performed on the west coast of Norway to study propagation effects (in particular refraction and turbulence effects) close to the sea surface. A complete meteorological station and a temperature profile buoy were used to characterize the propagation environment, while sensor height was logged continuously. Land and ship mounted sources were studied using infrared (midwave IR and longwave IR FPAs) and visual cameras at about 4 m above mean sea level (MSL). The land-based sources were mounted about 2-13 m above MSL, while the ship mounted sources were 10 m above sea level. Both sub- and superrefractive conditions were studied during the trials. The sensors were mounted on a programmable motion controller, which allowed extraction of absolute apparent pitch angles of the imaged sources. Apparent horizon distances have been determined for the ship sources, while mirror plane positions and apparent elevation (pitch) angles have been determined for the land sources. In addition, normalized variance of intensity (scintillation index) has been calculated for a number of cases. The scintillation index can easily be converted to refractive index structure parameters (Cn2), one of the key parameters characterizing optical turbulence. Measurement results are compared to results from the IR Boundary Layer Effects Model (IRBLEM *). *) IRBLEM is proprietory to the Department for National Defence of Canada as represented by DRDC-Valcartier
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Lars Trygve Heen, Eirik Blix Madsen, and Oddvar Selnes "Measurements of IR and visual propagation in the marine boundary layer", Proc. SPIE 5572, Optics in Atmospheric Propagation and Adaptive Systems VII, (11 November 2004); https://doi.org/10.1117/12.565220
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KEYWORDS
Scintillation

Infrared cameras

Cameras

Sensors

Mid-IR

Visualization

Ocean optics

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