These ripples are high in the upper atmosphere. They’re thought to be caused by gravity waves. Photo copyright 2016 Xiao Shuai. Photo processing by Jeff Dai. Used with permission.

Jeff Dai, who has contributed many beautiful photos to EarthSky, wrote in late November:
A ‘mesospheric bore’ was captured from Mount Balang, Sichuan, China on November 24. The photographer reported seeing it with the unaided eye. The direction of these photos were toward the south, and the foreground mountain was illuminated by the rising moon.
Location: 30°53’54’’N and 102°54’03E.
Date and time: November 24, 2-4 a.m. (GMT +8)