Study on spectral transmission characteristics of the reflected and self-emitted radiations through the atmosphere

This paper is a part of developing a software that predicts spectral radiance from ground objects by considering spectral surface properties. The material surface properties are essential for determining the reflected radiance by solar energy and the self-emitted radiance from the object surface. We considered the composite heat transfer modes including conduction, convection and spectral solar irradiation for objects within a scene to calculate the surface temperature distribution. The software developed in this study could be used to model the thermal energy balance to obtain the temperature distribution over the object by considering the direct and diffuse solar irradiances and by assuming the conduction within the object as one-dimensional heat transfer into the depth. MODTRAN is used to model the spectral solar irradiation including the direct and diffuse solar energy components. Resulting spectral radiance in the MWIR (3~5 mum) region and LWIR (8~12 mum) regions arrived at the sensor are shown to be strongly dependent on the spectral surface properties of the objects.