Interesting article in several papers and elsewhere (various climate blogs) attributing our recent cold spell to "Global Warming/Climate Change/Climate Disruption.
www.guardian.co.uk/commentisfree/2010/dec/20/uk-snow-global-warming
www.dailymail.co.uk/sciencetech/article-1341388/Global-warming-Britain-longer-colder-winters-melting-sea-ice-plays-havoc-weather-patterns.html
to name but 2 sources.
However, a crucial part of the artcle states that
"The open sea, being darker, absorbed more heat from the sun in the warmer, light months. As it remained clear for longer than usual it also bled more heat into the Arctic atmosphere. This caused higher air pressures, reducing the gradient between the Iceland low and the Azores high." (Guardian)
"As the Arctic ice cap has melted the heat from the relatively-warm seawater escapes into the colder atmosphere above, creating an area of high pressure." (Mail)
I've waded through the 1680 comments on the Guardian site (got up early!) and nobody has asked or answered what seems to be a crucial question:-
How does heat rising into the atmosphere cause HIGH pressure? Surely it would cause LOW pressure?
It's the process that causes tropical storms, thunderstorms etc - low pressure phenomena - isn't it?
So can you erudite people, fuelled by an excess of Christmas spirit, explain the logic to me of how putting heat into the atmosphere causes high pressure?
Phil
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Oh, and Independent says
"Their models found that, as the ice cap over the ocean disappeared, this allowed the heat of the relatively warm seawater to escape into the much colder atmosphere above, creating an area of high pressure surrounded by clockwise-moving winds that sweep down from the polar region over Europe and the British Isles"
Doesn't air circulate round High pressure clockwise and Low pressure anti-clockwise?
I'm confused!
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I might have missed your point Phil, but warmer means expansion/higher pressure doesn't it?
The rising bit is just convection? The heating increases the pressure?
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" The heating increases the pressure? "
Don't think so - because not in a container. I understood that rising air produces low pressure on earth's surface, sinking cold air produces high pressure
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www.weatherquestions.com/What_causes_high_pressure.htm
High pressure areas are usually caused by air masses being cooled, either from below (for instance, the subtropical high pressure zones that form over relatively cool ocean waters to the west of Califormia, Africa, and South America), or from above as infrared cooling of winter air masses over land exceeds the warming of those airmasses by sunlight.
As the airmass cools, it shrinks, allowing air from the surroundings to fill in above it, thus increasing the total mass of atmosphere above the surface, which then results in higher surface barometric pressures.
Suggest you correct them!
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I expect it is asking a bit much for a journalist to understand and explain science, bless them. "It's cold, we're all going to die" is about their limit. Anyway, I was disappointed by the Daily Wail as I was expecting them to attribute it to single parent mothers, and the culture of dependency.
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"Anyway, I was disappointed by the Daily Wail as I was expecting them to attribute it to single parent mothers, and the culture of dependency."
Even more surprising, they didn't say what effect it would have on house prices!
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Q on "Global Warming" article - PhilW
