Inferior mirage of a ship
The surfer in the foreground is either unaware of the interesting mirage in the distance or doesn’t realize it’s a mirage and is waiting for this “huge” ship’s wake-wave. This photo was taken in the Pacific Ocean near San Francisco on January 13, 2013 – a very cold winter’s day for coastal California. Cold, calm and clear weather conditions along a shore are great for detecting inferior mirages.
With an inferior mirage, the image is below the real object. According to atmospheric optics expert, Les Cowley, in this case a layer of abnormally warm air was situated beneath a cooler air layer. Light passing at low angles across the different air layers was refracted so that rays coming from the top of the boat appeared to be coming upward from thehorizon. Our brain interprets this as a reflection from the water. Note that the horizon is missing, and the base of the boat can’t be seen either below or above the line joining the “real” view and the mirage. This is referred to as thevanishing-line effect.
Most often, inferior mirages are observed in the deserts and often trick experienced and inexperienced travelers alike, and not only travelers. For example, during World War I (on 11 April 1917), the fighting between the British and the Turks in Mesopotamia had to be temporarily suspended owing to a mirage. Sometimes people who get lost in deserts are relieved by seeing an oasis only to realize later on that it was just a mirage. David Livingstone wrote:
“A mirage can never be reached and it leads travelers astray, luring them farther and farther into the heart of the waste, ever retreating before them as they pursued it, and not finally disappearing till its deluded victims had irrecoverably lost themselves in the pathless sands.”