Deep Space Observations of Terrestrial Glitter.

Deep space climate observatory (DSCOVR) spacecraft drifts about the Lagrangian point ≈1.4–1.6 × 106 km from Earth, where its Earth polychromatic imaging camera (EPIC) observes the sun‐lit face of the Earth every 1 to 2 hours. At any instance, there is a preferred (specular) spot on the globe, where a glint may be observed by EPIC. While monitoring reflectance at these spots (terrestrial glitter), we observe occasional intense glints originating from neither ocean surface nor cloud ice and we argue that mountain lakes high in the Andes are among the causes. We also examine time‐averaged reflectance at the spots and find it exceeding that of neighbors, with the excess monotonically increasing with separation distance. This specular excess is found in all channels and is more pronounced in the latest and best‐calibrated version of EPIC data, thus opening the possibility of testing geometric calibration by monitoring distant glitter. Plain Language Summary: We find that bright reflections of sunlight (glints) observed by a satellite camera, a million miles away can help with accurately determining location of each image pixel. In addition to previously observed glints from the ocean surface and clouds, we detect overwhelmingly bright glints off high mountains in the Andes, likely caused by calm small lakes. Key Points: While most glints observed by EPIC come from ocean surfaces or ice clouds, some are found here to originate from small lakes, high in the AndesMonitoring of global specular spots (terrestrial glitter) shows higher time‐averaged reflectance at specular spots than elsewhereThis specular excess reflectance becomes more pronounced as geolocation improves. Conversely, specular excess can be used to monitor geolocation [ABSTRACT FROM AUTHOR]