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Inferior mirage

From Openwaterpedia

noun - Inferior mirage is an inverted image that appears below the real object, caused by thermal inversion. In bodies of water, it becomes visible when the air is warmer than the water. In the desert, it appears as a lake of water (desert mirage). On tarmac roads, it may seem that water or even oil has been spilled (highway mirage). A layer of hot air next to a cooler layer causes light to bend, resulting in the appearance of a second image of the object below.