![]() The ghost can appear to move (sometimes suddenly) because of the movement of the cloud layer and variations in density within the cloud. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges their shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds, or when there are no reference points by which to judge its size. The light projects their shadow through the mist, often in a triangular shape due to perspective. The "spectre" appears when the sun shines from behind the observer, who is looking down from a ridge or peak into mist or fog. BBC Newsround Brocken Spectre: What is it and what causes it 31 October 2019 WATCH: BBC Weatherman explains this strange phenomenon Just in time for Halloween, heres a spooky story that. The Brocken spectre was observed and described by Johann Silberschlag in 1780, and has since been recorded often in literature about the region.Ī semi-artificial Brocken spectre created by standing in front of the headlight of a car, on a foggy night. The phenomenon can appear on any misty mountainside, cloud bank, or from an airplane, but the frequent fogs and low-altitude accessibility of the Brocken, a peak in the Harz Mountains in Germany, have created a local legend from which the phenomenon draws its name. ![]() The figure's head is often surrounded by the halo-like rings of coloured light forming a glory, which appears opposite the Sun's direction when uniformly-sized water droplets in clouds refract and backscatter sunlight. Both months have been outranked by October 2000, totalling 188mm and dry August 1995 with a mere 9.1mm.A Brocken spectre (German: Brockengespenst), also called Brocken bow, mountain spectre, or spectre of the Brocken is the magnified (and apparently enormous) shadow of an observer cast upon clouds opposite the Sun's direction. Between 19 the driest month was April 1984 with a total of 10.8mm and wettest October 1987 with a total of 180.2mm. Autumnal rainfall increased from 257.9mm to 270.3mm - which is about 5.2%, and winter rainfall by about 4.3%.Īlso extreme months turned even a little more extreme. However, autumn (September, October, November) and winter (December, January and February) turned significantly wetter, while spring (March, April and May) and summer (July, August and September) became slightly drier. This is about 1.3% and doesn't seem much at all. Mean total annual rĪinfall increased from 915mm to 926.9mm. For example, if you compare the 1961-1990 average rainfall with the period of 1971-2000, you will find that England and Wales turned slightly wetter over the last 30 years. For example, in the year 2001 the old 1961-1990 reference has been replaced by the 1971-2000 period.Ĭomparing them provides a lot of important facts on how our most recent climate might have changed. However, with every new decade this period will be shifted ten years further ahead. Temperature actual monthly rainfall will be compared against a 30-year average known as the standard reference period. The rainfall history goes back until 1766 and is one of the longest rainfall records in the world. In addition to the Central England Temperature (CET) the Hadley Centre is monitoring the average monthly rainfall over England and Wales.
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