南极海冰覆盖范围创新记录
文章来源:未知 文章作者:enread 发布时间:2014-10-09 06:39 字体: [ ]  进入论坛
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Sea ice surrounding Antarctica reached a new record high extent this year, covering more of the southern oceans than it has since scientists began a long-term satellite record to map sea ice extent in the late 1970s. The upward trend in the Antarctic, however, is only about a third of the magnitude of the rapid loss of sea ice in the Arctic Ocean. The new Antarctic sea ice record reflects the diversity and complexity1 of Earth's environments, said NASA researchers. Claire Parkinson, a senior scientist at NASA's Goddard Space Flight Center, has referred to changes in sea ice coverage2 as a microcosm of global climate change. Just as the temperatures in some regions of the planet are colder than average, even in our warming world, Antarctic sea ice has been increasing and bucking3 the overall trend of ice loss.
 
"The planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected, but just like with global warming, not every location with sea ice will have a downward trend in ice extent," Parkinson said.
 
Since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometers) of ice a year; the Antarctic has gained an average of 7,300 square miles (18,900 sq km). On Sept. 19 this year, for the first time ever since 1979, Antarctic sea ice extent exceeded 7.72 million square miles (20 million square kilometers), according to the National Snow and Ice Data Center. The ice extent stayed above this benchmark extent for several days. The average maximum extent between 1981 and 2010 was 7.23 million square miles (18.72 million square kilometers).
 
The single-day maximum extent this year was reached on Sept. 20, according to NSIDC data, when the sea ice covered 7.78 million square miles (20.14 million square kilometers). This year's five-day average maximum was reached on Sept. 22, when sea ice covered 7.76 million square miles (20.11 million square kilometers), according to NSIDC.
 
A warming climate changes weather patterns, said Walt Meier, a research scientist at Goddard. Sometimes those weather patterns will bring cooler air to some areas. And in the Antarctic, where sea ice circles the continent and covers such a large area, it doesn't take that much additional ice extent to set a new record.
 
"Part of it is just the geography and geometry. With no northern barrier around the whole perimeter4 of the ice, the ice can easily expand if conditions are favorable," he said.


点击收听单词发音收听单词发音  

1 complexity KO9z3     
n.复杂(性),复杂的事物
参考例句:
  • Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
  • The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。
2 coverage nvwz7v     
n.报导,保险范围,保险额,范围,覆盖
参考例句:
  • There's little coverage of foreign news in the newspaper.报纸上几乎没有国外新闻报道。
  • This is an insurance policy with extensive coverage.这是一项承保范围广泛的保险。
3 bucking a7de171d35652569506dd5bd33b58af6     
v.(马等)猛然弓背跃起( buck的现在分词 );抵制;猛然震荡;马等尥起后蹄跳跃
参考例句:
  • a bucking bronco in the rodeo 牛仔竞技表演中一匹弓背跳跃的野马
  • That means we'll be bucking grain bags, bustin's gut. 那就是说咱们要背这一袋袋的谷子,得把五脏都累坏。 来自辞典例句
4 perimeter vSxzj     
n.周边,周长,周界
参考例句:
  • The river marks the eastern perimeter of our land.这条河标示我们的土地东面的边界。
  • Drinks in hands,they wandered around the perimeter of the ball field.他们手里拿着饮料在球场周围漫不经心地遛跶。
TAG标签: sea ice Antarctica
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