北极海底甲烷的排放量超估算值两倍-凯发k8官网

北极海底甲烷的排放量超估算值两倍
文章来源:未知 文章作者:enread 发布时间:2013-11-26 07:53 字体: [ ] 
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the seafloor off the coast of northern siberia is releasing more than twice the amount of 1(甲烷) as 2 estimated, according to new research results published in the nov. 24 edition of the journal nature geoscience. the east siberian arctic shelf is 3 at least 17 teragrams of the methane into the atmosphere each year. a teragram is equal to 1 million tons.
 
"it is now on 4 with the methane being released from the arctic 5, which is considered to be one of the major sources of methane in the northern hemisphere," said natalia shakhova, one of the paper's lead authors and a scientist at the university of alaska fairbanks. "increased methane releases in this area are a possible new climate-change-driven factor that will strengthen over time."
 
methane is a greenhouse gas more than 30 times more 6 than carbon dioxide. on land, methane is released when previously frozen organic material 7. in the seabed, methane can be stored as a pre-formed gas or asmethane hydrates. as long as the subsea permafrost(永久冻土) 8 frozen, it forms a cap, effectively trapping the methane beneath. however, as the permafrost 9, it develops holes, which allow the methane to escape. these releases can be larger and more 10 than those that result from 11.
 
the findings are the latest in an 12 international research project led by shakhova and igor semiletov, both researchers at the uaf international arctic research center. their twice-yearly arctic expeditions have revealed that the subsea permafrost in the area has 13(融解) much more extensively than previously thought, in part due to warming water near the bottom of the ocean. the warming has created conditions that allow the subsea methane to escape in much greater amounts than their earlier models estimated. frequent storms in the area hasten its release into the atmosphere, much in the same way stirring a 14 releases the carbonation more quickly.
 
"results of this study represent a big step forward toward improving our understanding of methane 15 from the east siberian arctic shelf," said shakhova. she 16 that while the esas is unusual in its expansive and shallow nature, the team's findings there speak to the need for further exploration of the subsea arctic. "i believe that all other arctic shelf areas are significantly underestimated and should be paid very careful attention to."
 
the east siberian arctic shelf is a methane-rich area that 17 more than 2 million square kilometers of seafloor in the arctic ocean. it is more than three times as large as the nearby siberian wetlands, which have been considered the primary northern hemisphere source of 18 methane. previous estimates performed for the esas suggested that the area was releasing 8 teragrams of methane into the atmosphere yearly.
 
during field expeditions, the research team used a variety of techniques -- including sonar and visual images of methane bubbles in the water, air and water sampling, seafloor drilling and temperature readings -- to determine the conditions of the water and permafrost, as well as the amount of methane being released.
 
methane is an important factor in global climate change, because it so effectively traps heat. as conditions warm, global research has indicated that more methane is released, which then stands to further warm the planet. scientists call this phenomenon a positive feedback loop.
 
"we believe that the release of methane from the arctic, and in particular this part of the arctic, could impact the entire globe," shakhova said. "we are trying to understand the actual contribution of the esas to the global methane budget and how that will change over time."


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1 t1eyx     
n.甲烷,沼气
参考例句:
  • the blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
  • methane may have extraterrestrial significance.甲烷具有星际意义。
2 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。
3 bfb798c258dda800004b5c1d9ebef748     
消除; 泄去; 排去; 通风
参考例句:
  • but, unexpectedly, he started venting his spleen on her. 哪知道,老头子说着说着绕到她身上来。 来自汉英文学 - 骆驼祥子
  • so now he's venting his anger on me. 哦,我这才知道原来还是怄我的气。
4 ok0xr     
n.标准,票面价值,平均数量;adj.票面的,平常的,标准的
参考例句:
  • sales of nylon have been below par in recent years.近年来尼龙织品的销售额一直不及以往。
  • i don't think his ability is on a par with yours.我认为他的能力不能与你的能力相媲美。
5 dmtww     
n.苔原,冻土地带
参考例句:
  • the arctic tundra is at the top of the world around the north pole.北极冻原是指北极点周边的地区,是世界最高的地方。
  • there is a large amount of methane gas under the siberian tundra.西伯利亚的冻土地带之下有大量的甲烷气体。
6 c1uzk     
adj.强有力的,有权势的;有效力的
参考例句:
  • the medicine had a potent effect on your disease.这药物对你的病疗效很大。
  • we must account of his potent influence.我们必须考虑他的强有力的影响。
7 104d7ddd5cfb119e99319744ced0efe9     
腐烂( decompose的第三人称单数 ); (使)分解; 分解(某物质、光线等)
参考例句:
  • the debris slowly decomposes into compost. 这些垃圾慢慢地分解成了堆肥。
  • plastic is a substance that hardly decomposes in the nature. 塑料是一种在自然中极难降解的物质。
8 1kmzty     
n.剩余物,残留物;遗体,遗迹
参考例句:
  • he ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • the remains of the meal were fed to the dog.残羹剩饭喂狗了。
9 4f4632289b8d9affd88e5c264fdbc46c     
n.(足以解冻的)暖和天气( thaw的名词复数 );(敌对国家之间)关系缓和v.(气候)解冻( thaw的第三人称单数 );(态度、感情等)缓和;(冰、雪及冷冻食物)溶化;软化
参考例句:
  • the sun at noon thaws the ice on the road. 中午的阳光很快把路上的冰融化了。 来自辞典例句
  • it thaws in march here. 在此地化雪的季节是三月。 来自辞典例句
10 2fdyh     
adj.突然的,意外的;唐突的,鲁莽的
参考例句:
  • the river takes an abrupt bend to the west.这河突然向西转弯。
  • his abrupt reply hurt our feelings.他粗鲁的回答伤了我们的感情。
11 anfzt     
n. 分解, 腐烂, 崩溃
参考例句:
  • it is said that the magnetite was formed by a chemical process called thermal decomposition. 据说这枚陨星是在热分解的化学过程中形成的。
  • the dehydration process leads to fairly extensive decomposition of the product. 脱水过程会导致产物相当程度的分解。
12 6rvzt     
adj.进行中的,前进的
参考例句:
  • the problem is ongoing.这个问题尚未解决。
  • the issues raised in the report relate directly to age concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。
13 fbd380b792ac01e07423c2dd9206dd21     
解冻
参考例句:
  • the little girl's smile thawed the angry old man. 小姑娘的微笑使发怒的老头缓和下来。 来自《简明英汉词典》
  • he thawed after sitting at a fire for a while. 在火堆旁坐了一会儿,他觉得暖和起来了。 来自《简明英汉词典》
14 cr3ye     
n.苏打水;汽水
参考例句:
  • she doesn't enjoy drinking chocolate soda.她不喜欢喝巧克力汽水。
  • i will freshen your drink with more soda and ice cubes.我给你的饮料重加一些苏打水和冰块。
15 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
16 5n4zxc     
adj.著名的,知名的
参考例句:
  • the local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • jim is noted for arriving late for work.吉姆上班迟到出了名。
17 cba8673f835839b92e7b81ba5bccacfb     
v.围绕( encompass的第三人称单数 );包围;包含;包括
参考例句:
  • the job encompasses a wide range of responsibilities. 这项工作涉及的职责范围很广。
  • its conservation law encompasses both its magnitude and its direction. 它的守恒定律包括大小和方向两方面。 来自辞典例句
18 6eayr     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
tag标签: coast methane seafloor
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