Miraged
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.
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