Development of an application scheme for the SELENE/SP lunar reflectance model for radiometric calibration of hyperspectral and multispectral sensors

We have developed an application scheme for conducting lunar calibration, one of the radiometric calibration methods for optical instruments onboard Earth-orbiting satellites and planetary explorers, with a newly developed hyperspectral lunar reflectance model based on SELENE/SP data. Because the model considers photometric properties (lunar surface reflectance and its dependences on incident, emission, and phase angles) with high spectral and spatial resolution (6-8 nm wavelength intervals and 0.5° grid meshes in lunar latitude and longitude), it enables us to simulate disk-resolved Moon radiance observed by not only multispectral but also hyperspectral sensors in space. Simulations of Moon observations conducted by ASTER with its three visible and near infrared bands, produced brightness profiles of simulated Moon images that show high correlation (more than 0.99) with the observed images in all bands, and the relative brightness of each pixel can be evaluated with 5% uncertainty. Consistency of dependence on phase angle and the libration effect between the SP model and another lunar reflectance model, ROLO, was also confirmed. The SP model will therefore be useful for evaluating the relative degradation of sensors in space.