Dew and dust layers on the surface of an object may significantly affect its thermal state and IR signature. Dew formation begins when the object surface temperature falls below atmospheric dew point temperature. Due to the latent heat released by the water accumulated on the surface the temperature drop stagnates and the object appears warmer then it would be without dew formation. An attempt was made to modify RadThermIR software to account for dew effects. A simple plate model and the more elaborate CUBI thermal modeling benchmarking object were used to study the extent to which dew may change thermal object signatures. A dust layer on an object surface may affect its optical properties and may act as additional thermal insulation when it is thick enough. Both effects influence the temperature and IR signature of the object. Parametric calculations by RadThermIR were performed for various dust thicknesses and optical properties. This data was used in an object/background contrast analysis. The obtained dust/dew layer results will be used in the planning of the next CUBI experiment in natural desert environments. In addition, CUBI data from another geographic location was used for studying different wind models resulting in some interesting conclusions concerning the applicability of the wind model used in RadThermIR.

Date Published: 15 April 2008
PDF: 10 pages
Proc. SPIE 6941, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XIX, 69410U (15 April 2008); doi: 10.1117/12.781548

Published in SPIE Proceedings Vol. 6941:
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XIX
Gerald C. Holst, Editor(s)