THE ANGULAR INFRARED EMISSIVITY OF THE SURFACE OF THE MOON

The Moon represents an valuable laboratory for studying the thermal emission properties of planetary surfaces. In general, this emission is not isotropic. Even for a perfectly flat homogeneous surface, the Fresnel laws dictate that intensity of emitted radiation should fall of with increasing emission angle if the emissivity of the surface is less than unity. For surfaces that display roughness at length-scales longer than the emitted wavelength, the effects of slopes and shadowing can result in significant isotropies in the angular distribution of radiated emission. The Lunar Reconnaissance Diviner Lunar Radiometer Experiment has acquired a unique mapping dataset of the Moon that includes extensive nadir observations as well as off-nadir views. As a Diviner team member, Joshua Bandfield was instrumental in the design and analysis of these observations. In this talk, I will review what we have learned about the angular infrared emissivity of the Moon from these observations, as well as from associated laboratory experiments and models.