shadow

Above the arctic in the clouds there was an extraordinary display and the residents were delighted to see it .  A local observer in Norway  Ramune  Sapailaite captured the phenomenon on her mobile. When the sunset is nearing the clouds it would explode.  It is a very rare atmospheric phenomena  known as nacreous clouds.  There is no moisture in the earth’s stratosphere and so  cloud formation is not possible. When temperatures plummet to around – 85 degree Celsius that low only under extreme conditions in Arctic winter ice particles will be formed  from water vapour. It’s these particles that scatter high altitude and it’s visible when the sun is below the horizon.  Given the timing this week’s sightings are particularly unusual. It’s usually in January  they make their first appearance ,  but this year’s  early onset in December suggests atypical Arctic winter. In stratospheric chemistry they play a crucial role as these clouds are related to ozone depletion. The destruction impact of chlorine on the ozone layer is prevented by these clouds.  The nitrogen compounds are removed by these clouds. While it’s a treat for skywatchers ,  it’s a subject of concern for scientists  as they discuss about the atmospheric changes.

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