北半球今冬可能为寒冬
文章来源:未知 文章作者:enread 发布时间:2011-10-16 07:34 字体: [ ]  进入论坛
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A cyclical drop in the sun's radiation can trigger unusually cold winters in parts of North America and Europe, scientists say, a finding that could improve long-range forecasts and help countries prepare for blizzards1.

科学家表示,太阳辐射的周期性减弱可能导致北美洲和欧洲部分地区出现异常“冷冬”。这项科学发现可以改进长期天气预报,帮助各国准备好应对风雪。

Scientists have known for a long time that the sun has an 11-year cycle during which radiation measured by sunspots on the surface reaches a peak then falls. But pinning down a clear link to weather has proved harder.

"Our research confirms the observed link between solar variability and regional winter climate," lead author Sarah Ineson of the UK Met Office told the reporters in an email. The study was published in the journal Nature Geoscience on Monday.

Her team focused on data from the recent solar minimum during 2008-10, a period of unusual calm for the sun and intense winters in the United States and parts of Europe that shut down air travel and disrupted businesses.

The researchers found that a reduction in ultraviolet (UV) radiation from the sun can affect high-altitude wind patterns in the Northern Hemisphere, triggering cold winters.

"While UV levels won't tell us what the day-to-day weather will do, they provide the exciting prospect2 of improved forecasts for winter conditions for months and even years ahead. These forecasts play an important role in long-term contingency3(偶然性) planning," Ineson, a climate scientist, said.

Ineson and colleagues from the Imperial College London and the University of Oxford4 used satellite data that more accurately5 measures UV radiation from the sun and found a much greater variability than previously6 thought.

They found that in years of low activity, unusually cold air forms high in the atmosphere over the tropics. This causes a redistribution of heat in the atmosphere, triggering easterly winds that bring freezing weather and snow storms to northern Europe and the United States and milder weather to Canada and the Mediterranean7.

When solar UV radiation is stronger, the opposite occurs.

Ineson's team used the data in a complex computer model that simulates long-term weather patterns. The model successfully reproduced what scientists have observed happening in the upper atmosphere during changes in solar radiation.

More study was needed, though. A key uncertainty8 in the experiment lay in the satellite data used, because it spans only a few years. "So questions remain concerning both accuracy and also applicability to other solar cycles," she said.



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1 blizzards 1471207223cd592610a59597189c4c03     
暴风雪( blizzard的名词复数 ); 暴风雪似的一阵,大量(或大批)
参考例句:
  • Even in the summertime we might be struck by blizzards. 甚至在夏天,我们也可能受到暴风雪的袭击。
  • Blizzards battered Britain for the third day. 大风雪袭击英国已进入第三天。
2 prospect P01zn     
n.前景,前途;景色,视野
参考例句:
  • This state of things holds out a cheerful prospect.事态呈现出可喜的前景。
  • The prospect became more evident.前景变得更加明朗了。
3 contingency vaGyi     
n.意外事件,可能性
参考例句:
  • We should be prepared for any contingency.我们应该对任何应急情况有所准备。
  • A fire in our warehouse was a contingency that we had not expected.库房的一场大火是我们始料未及的。
4 Oxford Wmmz0a     
n.牛津(英国城市)
参考例句:
  • At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
  • This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。
5 accurately oJHyf     
adv.准确地,精确地
参考例句:
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
6 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
7 Mediterranean ezuzT     
adj.地中海的;地中海沿岸的
参考例句:
  • The houses are Mediterranean in character.这些房子都属地中海风格。
  • Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要冲。
8 uncertainty NlFwK     
n.易变,靠不住,不确知,不确定的事物
参考例句:
  • Her comments will add to the uncertainty of the situation.她的批评将会使局势更加不稳定。
  • After six weeks of uncertainty,the strain was beginning to take its toll.6个星期的忐忑不安后,压力开始产生影响了。
TAG标签: winter cold sun
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