Heat haze [edit] Heat haze, also called heat shimmer, describes the inferior mirage observed when viewing items through a mass of heated air. Typical instances when heat haze takes place include images of things seen throughout asphalt concrete (likewise referred to as tarmac) roads and over masonry roofs on hot days, above and behind fire (as in burning candle lights, patio area heaters, and campfires), and through exhaust gases from jet engines.
Convection causes the temperature of the air to vary, and the variation between the hot air at the surface area of the roadway and the denser cool air above it produces a gradient in the refractive index of the air. This produces a blurred sparkling result, which hinders the ability to solve the image and increases when the image is amplified through a telescope or telephoto lens.
Light from the sky at a shallow angle to the road is refracted by the index gradient, making it look like if the sky is reflected by the road's surface. The mind analyzes this as a pool of water on the road, given that water likewise shows the sky. The illusion fades as the observer approaches the miraged things.
This sort of inferior mirage is frequently called a "desert mirage" or "highway mirage". Both sand and tarmac can become very hot when exposed to the sun, easily being more than 10 C (18 F) greater than the air a meter above, enough to make conditions appropriate to trigger the mirage.
Superior mirage [modify] A synthetic mirage, utilizing sugar services to simulate the inversion layers. A cat is seen browsing a glass, which has three layers of option, with decreasing refractive index from bottom to top. The feline appears in multiple images. This simulates an atmosphere with two inversion layers. An exceptional mirage is one in which the mirage image seems located above the genuine object.
This uncommon plan is called a temperature inversion, considering that warm air above cold air is the opposite of the typical temperature level gradient of the atmosphere during the daytime. Passing through the temperature inversion, the light rays are bent down, and so the image appears above the true item, thus the name exceptional.