Cloud Composition from the Analysis of Sun Glints Off Horizontally Oriented Ice Crystals

Satellite images often feature sun glints caused by the specular reflection of sunlight from horizontally oriented ice crystals occurring in clouds. Such glints can complicate the interpretation of observations but can also provide insights into the composition of ice and mixed-phase clouds. Satellite observations of sun glint offer excellent opportunities to narrow the gaps in our knowledge about the prevalence and characteristics of horizontally oriented ice crystals, which cause significant uncertainties in satellite retrievals of cloud properties and in calculations of cloud radiative forcing and cloud lifetime.

This presentation will briefly describe the operational sun glint product of the Earth Polychromatic Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) spacecraft. Subsequently, it will also discuss the impact of glints on cloud detection and on retrievals of cloud properties reported in the EPIC operational cloud product, namely cloud optical thickness and cloud altitude. Finally, the presentation will discuss glint statistics based on satellite observations that provide information about the prevalence of horizontally oriented crystals in tropical ice clouds.