Terrestrial Glints Seen from the Lagrangian Point: Clouds vs. Oceans

EPIC, a polychromatic imaging camera onboard DSCOVR (Deep Space Climate Observatory) spacecraft has delivered nearly hourly observations of the entire sunlit face of the Earth for a couple of years now. Recent work (Marshak et al, 2017, GRL) has shown that the unexpected bright flashes (glints) of light over ocean and land are specular reflections of sunlight. Further work (Varnai, et. al., in preparation) now suggests, perhaps counter-intuitively, that cloud glints tend to be brighter than the ocean ones. Furthermore, the cloud glint occurrence rate is surprisingly high. We shall examine the relevant microphysics of ocean waves and ice particles within the context of these preliminary results on glints. The immense range of spatial scales, from micron-sized ice crystals to a million mile distance to the detector, makes this problem particularly compelling for extrapolation to even further reaches. To that end, we shall consider the plausibility of detecting starlight glints off faint companions in search for habitable exoplanets.