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  Mock mirage (M-Mir) green flash
 
     


Mock mirage sunset & green flash seen from the ESO La Silla Observatory, Chile altitude 2400m by astronomer Jesús Maíz Apellániz (site). M-Mir flashes are always below the astronomical horizon - the altitude helped increase the dip of the actual horizon and the space available for the mirage.
Image ©Jesús Maíz Apellániz

     
As the sun sinks it transforms into fantastical shapes. Sometimes an onion dome, sometimes a rectangle, sometimes stacked pancakes.

A piece breaks off the top and for a second or so shines green. This is another form of green flash, a mock mirage, M-Mir, flash.

The M-Mir flash is produced by an atmospheric temperature inversion.

Ordinarily the air temperature decreases monotonically with increasing height. An inversion is the presence of a kink in the temperature profile whereby layers exist that are warmer than usual.

An increase in temperature of only one or two degrees Celsius can produce distorted sunsets and green flashes.

You must be above the inversion layer to see a pure M-Mir flash. Inversion layers can, however, be quite close to ground or ocean.

Sometimes atmospheric waves cause the inversion layer to undulate and then a variant of the M-Mir flash is visible from below it.