Weather expert predicts start of autumn weather in Aylesbury Vale
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Rainbows are a branch of meteorology referred to as atmospheric optics, and they are created as light scatters through raindrops, with the visible light spectrum separated for the curve of colours. Ice crystals, dust, and even temperature gradients in the atmosphere can affect light for a myriad of optics.
A muted version of a rainbow can be seen within fog, this aptly named a fogbow. Fog and low cloud can also create a Brocken spectre, this a shadow of an observer cast onto the fog when the sun is positioned behind the subject. Brocken spectres can be surrounded by rainbow rings, these are known as Glories.
Halos are created by ice crystals high up in the atmosphere. Circular halo’s can be seen when the sun is low in the sky, with sundogs – bright rainbow-like spots – seen to the left and right of the sun too.
Above a circular halo another curve of iridescence can be seen, this is known as a tangent arc.
Sunset mirages and the infamous ‘floating ships’ are another type of optic, these however are created when the layers of the atmosphere have a strong temperature gradient. The different densities of the air refract light at different angles, this distorting the image for us to see.
Rainbows may not be on the agenda over the coming days but mainly dry weather is expected with an increasingly autumnal feel, with temperatures taking a little dip below the average for the time of year.