Polar stratospheric clouds at sunset. These are the nacreous or mother-of-pearl type of polar stratospheric cloud (PSC). PSCs are high-altitude icy cl

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Polar stratospheric clouds at sunset. These are the nacreous or mother-of-pearl type of polar stratospheric cloud (PSC). PSCs are high-altitude icy clouds that are found in the polar stratosphere at heights of about 24 kilometres. They only form during winter when the temperature drops below around -80 degrees Celsius. PSCs play a key role in the destruction of ozone by chlorine. They convert harmless forms of chlorine into highly-reactive forms. Chlorine is carried into the stratosphere in CFCs (chlorofluoro- carbons), gases used as refrigerants and during foam plastic manufacture. Photographed over Swedish Lapland.

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Size: 4504px × 3116px
Photo credit: © DAVID HAY JONES/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

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