s possible to sometimes hear FM radio (or watch VHF-LO band TV) broadcasts from otherwise impossible distances as far as a few hundred miles distant on foggy nights. The signal, still powerful enough to be received even at hundreds or rarely, thousands, of miles, would normally be refracted up and away from the ground-based antenna, is instead refracted down towards the earth by the temperature-inversion boundary layer. This phenomenon i s called tropospheric ducting. It is also referred to as skip by small radio operators and Ham operators. Along coast lines during Autumn and Spring many FM radio stations are plagued by severe signal degradation causing them to sound like "scrambled eggs ".
Inversions can magnify the so called "green flash": a phenomenon occurring at sunrise/sunset, usually visible for a few seconds, in which the sun's green light is isolated due to dispersion - the shorter wavelength is refracted most, so it is the first/last light from the upper rim of the solar disc to be seen.
In addition, when an inversion layer is present (for example early in the morning when ground-level air temperatures are cool, and high-level air temperatures are warmer), if a sound or explosion occurs at ground level, the sound wave can get totally reflected from the warmer upper layer (in which the sound travel faster, i.e. the air has lower acoustic refractive index, so the sound can undergo total internal reflection) and return back to ground level; the sound is therefore heard much further than normal. The shockwave from an explosion can be reflected by an inversion layer in much the same way as it bounces off the ground in an air-burst and can cause additional damage as a result. This phenomenon killed three people in the RDS-37 nuclear test.
In an inversion, vertical motion in the atmosphere is suppressed because the atmosphere is stable. Hence vertical heat transport by eddies is suppressed; this reduced (downwards) heat transport leads to further cooling of the lower surface. This can lead to an effective decoupling of the atmosphere from the surface in extreme conditions, such as may be found in Antarctica during the polar night, where inversions greater than 25 В° C commonly occur. When it happens the sky is a reddish color.
Internet sours
1. # "#"> # "#"> # "#"> # "#"> # "#"> Http://en.wikipedia.org/wiki/Inversion_ (meteorology)
