Optical Phenomena
In the Arctic, people frequently see unique and beautiful optical phenomena. The atmospheric conditions that can lead to the development of these phenomena are the suspension of ice crystals in the atmosphere, the presence of strong surface inversions that refract light rays, the reflection of light by cloud bottoms, and interactions between the solar wind and gases in the upper atmosphere. Optical phenomena observed in the Arctic include the Aurora Borealis, Halos (sun dogs and fog bows), Coronas and Anticoronas, Water Sky and Ice Blink, Superior Mirages (looming, towering, fata morgana), and Optical Haze.
Acoustic Phenomena
People frequently report supernormal audibility in Arctic regions. As with optical phenomena, this phenomenon occurs when the vertical density structure of the air causes refraction, but instead of light being refracted, sound waves are refracted. The air near the surface tends to be colder and more dense than air higher up, causing sound waves to tend to bend down toward the surface rather than up away from the earth as they do in more temperate latitudes where air temperature on average decreases with height.
The range at which sound can be heard depends on the temperature (and hence density) structure of the air, the speed and direction of the wind, and the rate at which sound energy is absorbed by the earth's surface. For instance, soft snow absorbs sound energy very efficiently, effectively muting the transmission of sound. In contrast, a hard-crusted snow surface absorbs little energy and a smooth ice surface is an almost ideal reflector of sound. Given the right conditions, conversations can sometimes be heard up to three kilometers away.
