Thermal Images of Sky and Sea-Surface Background Infrared Radiation
Abstract
Thermal Images of the sky and the sea surface background radiance were analyzed using the AGA Thermovision 780 system. Calculated sky radiance was compared with that predicted by the computer code LOWTRAN 6. The Schwartz-Hon computer model for the emissivity of the sea surface was validated using the results from AGA measurements and LOWTRAN 6. The factors which affect the radiance measurements were determined, and the degree of influence they exert was estimated. The radiance emitted from an overcast sky was found to be higher than that emitted from a clear sky. The wind speed reduces significantly the infrared sky radiance. Emissivity of the sea surface depends upon the wave roughness, remaining almost constant with the viewing angle. The whole result showed that LOWTRAN 6 provides a good prediction of the atmospheric radiance with deviation from measurement generally within 10% with cases to 15%, for the elevation angle range from 0 to 19 degrees and that the Schwartz-Hon model agrees well with observation showing deviation varying up to 14% in the elevation angle range from 5 to 10 degrees. Keywords: Thermal radiation, Emissivity, Blackbody radiators, Background radiance, Computer code LOWTRAN 6, Thermovision 780 system, Schwartz-hon model, Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA205819
Entities
People
- Panagiotis Psihogios
Organizations
- Naval Postgraduate School