Sunset & Green Flashes -
Imaged from San Francisco my Mila Zinkova (site).
Sunset mirages result when low sun rays are refracted between air layers of different temperature and density. In this sunset, the cold Californian offshore ocean current and warm air from onshore have produced multiple stacked temperature inversions. A single inversion layer can produce a mirage having three images of the sun. The upper one is erect and descending, one of the lower ones is also erect but the other is inverted and ascending! Multiple layers give us the complex and fantastical shapes here.
Mirages do more - they can produce green flashes. Close to the horizon the sun's upper limb is always coloured green because green rays are refracted by the atmosphere more strongly than red making the 'green sun' appear slightly higher. This green rim is too narrow to be visible but mirages can greatly magnify the solar image in the vertical direction. The result - a green flash.
Image ©Mila Zinkova, shown with permission.