Bounding uncertainty in Monte Carlo ray-trace models

Abstract

In a previous effort the authors developed a methodology for describing uncertainty in thermal radiation Monte Carlo ray- trace (MCRT) analyses. An application to radiometric channels used in space-based observations such as those provided by NASA's Clouds and the Earth's Radiant Energy System (CERES) was reported.. In the previous study preliminary attempts were presented to confirm the theory. In the current effort extension and modifications of the previous theory are formulated and new examples are presented to confirm the extended theory. A generic MCRT- based computational environment that simulates radiative exchange among surfaces in enclosures is used to obtain performance estimates of a simple cavity-type thermal radiation detector. Standard statistical methods are used to interpret the results as uncertainties and their related confidence intervals. The example problem is used as a vehicle to verify the modified theory. The authors then demonstrate the theory in a more complex situation that of a high-level numerical model used to predict the dynamic opto- electro thermal behavior of the CERES radiometric channels.