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.
Accurate thermal modeling requires verification and validation of the model and software being used. For basic evaluation of thermal prediction models and software tools, a generic model - CUBI was build. The model was designed to have simple geometry yet, consisted of similar characteristics as of a ground vehicle. The model was equipped with thermocouples for measuring its temperature variations and was placed in a typical desert environment for field testing. The experimental setup also included a meteorological station. The data collected was used for the thermal behavior analysis of the generic model and for comparison with the thermal calculations predictions. Comparison of the results shows sufficient compliance but yet reviles some issues in the modeling that should be addressed.