Investigation of Field-Collected Data Using Diffuse and Specular, Forward and Reverse Radiative Transfer Models.

摘要

This research focuses on investigating the effect of specular and diffuse properties of a set of eight materials on diffuse-only and diffuse-specular radiative transfer models in the wavelength range of 7-14 microns. The materials were selected and measured by the Sensors Directorate, Air Force Research Laboratory (AFRL/RY) as a set of panels in two orientations, flat and at 45 with respect to the ground, where the materials range in reflective and specular properties. The collected field data includes sky down-welling spectral radiance, ground spectral radiance, panel temperatures, and panel spectral reflected radiance at both orientations. The radiative transfer models used in this research use field- and laboratory-collected data to calculate the spectral reflected radiance from each panel. The laboratory-collected data is comprised of spectral hemispherical, specular, and diffuse directional reflectance (HDR, SDR, and DDR) at incident angles of 20 , 30 , 40 , 45 , 50 , 60 , and 70 , as collected by an SOC-100 HDR Reflectometer from Surface Optics Corporation. The modeled spectral reflected radiances are compared to field-collected spectral reflected radiances in order to gauge each radiative transfer model for its accuracy in modeling each panel. Additionally, a diffuse-only reverse radiative transfer model is developed and used in order to model the spectral HDR of the materials. The modeled spectral HDR values are compared to laboratory-collected spectral HDR data, and the reverse model is gauged for its accuracy in modeling each panel.