Hot Road Inferior Mirage_(2018-05-23_5049a+5049b)

            Inferior 'Hot-road' Mirage:   

The hot-road mirage is one of the most commonly seen mirages, giving the illusion of an area of water on a road surface. A mirage is an optical phenomenon produced when light is refracted, or bent, by passing through layers of air of different temperature / density resulting in at least one inverted image.

This picture shows a 'hot-road' mirage on a road in Twyford, in  Berkshire, England in May 2018. The main, background photo shows the road photographed with the camera's zoom lens set to its highest telephoto setting (250 mm). This clearly illustrates that a mirage is a distant phenomenon. The inset image, overlaid on the main photo, is simply a highly-cropped part from the centre of the main photo. This shows the detail of the mirage more easily. 

The hot-road mirage occurs when there is a strong vertical temperature gradient near the ground surface, typically due to heating of the road surface by the Sun. Cooler air lies above warmer air. This type of mirage is known as an inferior mirage because the image of distant objects is displaced downwards. Rays of light from the sky and other objects (such as the vehicles on the road) are refracted as they pass through the air and are bent upwards towards the observer; thus, to the observer, refracted light from the sky appears as though it is water on the ground.

Here, slight undulations in the road surface and temperature gradients have resulted in several miraged images of the sky (giving the illusion of strips of water across the road). Miraged images of other objects (such as the roadside vegetation, the kerb and the cars) give the illusion of reflections in the apparent water. Perhaps the most interesting feature of this particular 'hot-road' mirage photo is the clearly inverted image of the front of the white car beneath the 'normal' upright image. [For the best detail, see the inset photo]. 

Note that in addition to the mirage, the slight distortions in the shape of the objects in the far distance (e.g. the 'normal' image of the car) are due to shimmer (perhaps more commonly known as heat haze). Shimmer is caused by short period fluctuations in the refractive index of the air as a result of the turbulent motion of small parcels of air. It typically occurs in summer when the Sun is shining brightly and the surface is hot, resulting in rising air currents.

Taken in: UK / England / Twyford / Twyford (show map)

Taken on: May 23, 2018

Tags:

mirage

inferior mirage

road

hot-road

street $Everybody's photos tagged with refraction$ refraction

highway $Everybody's photos tagged with refracted$ refracted $Everybody's photos tagged with atmospheric refraction$ atmospheric refraction

zoom lens

telephoto

telescopic

miraged

car

hot-highway

Twyford

Berkshire

England

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Sets appears in: • Mirages

Groups appears in: • Road • Science Nerd Depot more » • Refraction • Science in pictures • fata morgana • For The Love Of Science! • optical phenomena « less

Camera: Canon EOS 1100D, f/7.1, 1/400 sec, 250mm, ISO 100 (more info) (hide info)

Camera:	Canon EOS 1100D
Lens:	EF-S55-250mm f/4-5.6 IS II
Aperture:	f/7.1
Exposure Time:	0.003 sec (1/400)
Focal Length:	250mm
ISO:	100
Exposure Bias:	0 EV
Flash:	Off, Did not fire
Exposure Program:	Not Defined
Exposure Mode:	Auto
Metering Mode:	Multi-segment
White Balance:	Auto
Color Space:	sRGB
Software:	Adobe Photoshop Elements 18.0 (Windows)
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