A radiosity model used for predicting effective hyperspectral emissivity spectra and radiant temperatures for rough surfaces has been developed. Here we compare the computer model results to analytic model results in order to verify that the computer model is working properly, and validate the model results by comparison to spectra measured in the field by an hyperspectral imaging spectrometer. We measured a cm-scale DEM of the test scene using a tripod-based LiDAR. The discrepancies between analytical and modeled values are less than 0.01%. Modeled emissivity spectra deviate from the measured by no more than 0.015 emissivity units.