A discovery that it is much colder over the South Pole that believed has exposed a major flaw in the computer models used to predict global warming, a new scientific paper claims.
United States scientists based at Amunden-Scott South Pole Station say they have measured the temperature of the atmosphere 30km to 100km over the pole and found it is 20degC to 30degC colder than computer models showed.
Various models are used to predict global climate and some assumptions have had to be made, including air temperatures over Antarctica.
Chester Gardner, a professor of electrical and computer engineering at the University of Illinois, Weilin Pan, a doctoral student at Illinois, and Ray Roble, of the US National Centre for Atmospheric Research, writing in the American Geophysical Union Letters, say the models are wrong.
'Because of the obvious challenges, until now, the only temperature data we have had from either North or South Poles has been from surface measurements and weather balloons that don't go any higher than about 20-30km's,' Gardiner said.
The researchers used a laser radar system from the South Pole to make the first measurements of the temperature higher up and found it was much colder than assumed.
Global warming could be caused by greater concentrations of carbon dioxide (CO²), which is a strong absorber of infrared radiation.
In the lower atmosphere, CO² absorbs the heat. While CO² also emits heat other CO² absorbs it. In the thinner stratosphere and mesosphere, much of the heat emitted by CO² is radiated into space and so in the upper atmosphere the primary effect of CO² is cooling.
'Thus, as CO² levels continue to rise in the atmosphere, we expect the lower atmosphere to continue warming while the upper atmosphere…will cool.'
Antarctica receives little sunlight during winter and its atmosphere is sealed off by a vortex of winds preventing warmer air from lower latitudes travelling to the Pole.
'As a consequence the region cools to very low temperatures in winter, primarily by radiation of heat into space.'
In May, June and July the stratosphere was considerably colder than model predictions. The greatest difference occurred in July, when the measured stratosphere temperature was about minus 17 degC to about 4 degC by the models.
'Current global circulation models apparently over-predict the amount of down-welling, because they show warmer temperatures that we observe,' Gardner said.
Their measurements will be a baseline for future temperature studies.
'We believe a major flaw in current models is the way they account for compressional heating associated with down-welling over the polar cap in winter,' Gardner said.
'Of course you and I are really not interested in what happens above the South Pole. We do care about what happens where we live. Models can help predict those changes due to rising CO² levels but only if they give accurate results.
'Our South Pole measurements will help the modelers and theoreticians better understand the atmosphere and incorporate that understanding in their models, making their future predictions more accurate.'
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*I love Matty Enns*
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