Superior mirages are mirages of objects which occur above the object (as opposed to below the object, with an inferior mirage). Superior mirages may occur when there is a strong temperature inversion, such as warm air over a cold surface. They are very rare in many parts of the world, but seen frequently in polar regions. The temperature inversion refracts (bends) light rays downwards, and you see a mirage of an object above the object itself, usually mirrored upside-down.
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