北冰洋越来越像大西洋
文章来源:未知 文章作者:enread 发布时间:2017-04-10 08:17 字体: [ ]  进入论坛
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The Arctic is undergoing an astonishingly rapid transition as climate change overwhelms the region.
 
New research sheds light on the latest example of the changes afoot, showing that parts of the Arctic Ocean are becoming more like the Atlantic. Warm waters are streaming into the ocean north of Scandinavia and Russia, altering ocean productivity and chemistry. That's making sea ice recede1 and kickstarting a feedback loop that could make summer ice a thing of the past.
 
"2015 was a really anomalous2 year when we had problems finding a suitable ice flow to launch our drifting buoys3,"Igor Polyakov, an oceanographer at the University of Alaska who led the new study, said. "(There was) nothing like that in the past, and it became a motivation to our analysis: why was ice in 2015 so rotten? What drives this huge change?"
 
The findings, published in Science on Thursday, show that while warming air has a role to play, processes are playing out in the ocean itself that are fundamentally altering the region.
 
Those changes will have impacts on the people, plants and animals that call the Arctic home. They could also create more geopolitical tension as resources previously4 locked under ice become available and shipping5 lanes open up.
 
In the east Arctic Ocean, the shift is manifesting itself in changing the layers of the ocean. There's a cap of cold, less salty water that covers the eastern portion of the Arctic Ocean. Underneath6 it sits a pool of warm, salty Atlantic water that until recently hasn't been able to find a way to surface. That stratification of layers has kept ice relatively7 safe from its warm grip.
 
The ocean has become gradually less stratified since the 1970s. Using data from buoys and satellites, Polyakov and his colleagues have found a more marked shift over the past decade and a half. Since 2002, the difference in water temperatures between the layers has dropped by about 2°F.
 
In winter from 2013-2015, the cap separating the deep water and surface water disappeared completely in some locations, allowing the warm Atlantic waters to reach the surface and cut further into sea ice pack. At the same time, warm air has further reduced sea ice, which is allowing still more mixing of the ocean layers.
 
The result is a feedback loop that is essentially8 turning roughly a third of the eastern Arctic Ocean into something resembling the ice-free Atlantic Ocean.
 
"Rapid changes in the eastern Arctic Ocean, which allow more heat from the ocean interior to reach the bottom of sea ice, are making it more sensitive to climate changes," Polyakov said. "This is a big step toward the Arctic with seasonal9 sea-ice cover."


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1 recede sAKzB     
vi.退(去),渐渐远去;向后倾斜,缩进
参考例句:
  • The colleges would recede in importance.大学的重要性会降低。
  • He saw that the dirty water had begun to recede.他发现那污浊的水开始往下退了。
2 anomalous MwbzI     
adj.反常的;不规则的
参考例句:
  • For years this anomalous behaviour has baffled scientists.几年来这种反常行为让科学家们很困惑。
  • The mechanism of this anomalous vascular response is unknown.此种不规则的血管反应的机制尚不清楚。
3 buoys fc4788789ca537c33a2d5ad4b7a567db     
n.浮标( buoy的名词复数 );航标;救生圈;救生衣v.使浮起( buoy的第三人称单数 );支持;为…设浮标;振奋…的精神
参考例句:
  • The channel is marked by buoys. 航道有浮标表示。 来自《现代汉英综合大词典》
  • Often they mark the path with buoys. 他们常常用浮标作为航道的标志。 来自辞典例句
4 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。
5 shipping WESyg     
n.船运(发货,运输,乘船)
参考例句:
  • We struck a bargain with an American shipping firm.我们和一家美国船运公司谈成了一笔生意。
  • There's a shipping charge of £5 added to the price.价格之外另加五英镑运输费。
6 underneath VKRz2     
adj.在...下面,在...底下;adv.在下面
参考例句:
  • Working underneath the car is always a messy job.在汽车底下工作是件脏活。
  • She wore a coat with a dress underneath.她穿着一件大衣,里面套着一条连衣裙。
7 relatively bkqzS3     
adv.比较...地,相对地
参考例句:
  • The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
  • The operation was relatively painless.手术相对来说不痛。
8 essentially nntxw     
adv.本质上,实质上,基本上
参考例句:
  • Really great men are essentially modest.真正的伟人大都很谦虚。
  • She is an essentially selfish person.她本质上是个自私自利的人。
9 seasonal LZ1xE     
adj.季节的,季节性的
参考例句:
  • The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
  • The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。
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