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Village Web Site Forum
Denis Pickles
Norfolk
Thursday, February 28, 2008 08:14 |
Golden Sunset
I will not be the only one who has admired the wonderful photograph of the Pinnacles silhouetted against a gorgeous golden evening sky which has recently graced the Home Page Paul and I traded e-mails on the subject a few days ago. I was interested to know where he stood to take the shot and was surprised to be told that the viewpoint was almost in Eastburn in Knotts Lane.
But I wonder if Paul saw the article in the Telegraph printed a week ago, which gives an explanation for the 'Stunning Skies of this Bright, Beautiful Leap Year February'? You did? Well, perhaps others might be interested.
Philip Eden writes,
"The exeptional sunny spell may be interesting to the climatologist ........... but the accompanying spectacular sunrises and sunsets have ensured that it has had a much wider audience.
Stunning colours were observed from much of the country at both ends of the day and the sequence of sunsets between last Sunday and Tuesday were the most striking that I can remember. We were treated, not just to the usual golds and pinks, but to a whole succession of colours which lasted for an hour after the sun had dropped below the horizon.
On Monday, for instance, the setting sun was first of all accompanied by a bright, pale yellow - almost greeny yellow - glow across two thirds of the sky, then as the sun disappeared we cycled through yellowy-orange, crimson and finally a dull orangy-purple.
As the sky darkened, the colour retreated to the western horizon, but it did not fade until a full hour after the sun had gone. And here lies the explanation for the stunning display.
An hour after sunset the sun is approaching 10 degrees below the horizon and from there it can only illuminate something which is 20-25 kilometres above the ground. That is well into the stratosphere and indicates either stratospheric dust, or a very thin layer of ice-crystal cloud.
When a large high pressure system settles over the British Isles as occurred last week, it is often accompanied by a sharp drop in temperature in the lower stratosphere . Last Monday, for instance, it was -90C up there instead of a more usual -55C and at such a low temperature the residual moisture in the air frequently appears as an extremely tenuous veil of ice-crystal cloud. Such clouds are so thin they are invisible most of the time and can only be seen when lit from below by the setting sun."
So there you have it!
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paulw
webmaster
Thursday, February 28, 2008 09:33 |
Hi Denis, I hadn't seen the article - very interesting, thanks. I've added a photo of the sunset to the gallery.
Paul |
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