全球变暖情况下 区域性气候的变化模式
文章来源:未知 文章作者:meng 发布时间:2010-03-01 01:07 字体: [ ]  进入论坛
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Climate models project that the global average temperature will rise about 1°C by the middle of the century, if we continue with business as usual and emit greenhouse gases(温室气体) as we have been. The global average, though, does not tell us anything about what will happen to regional climates, for example rainfall in the western United States or in paradisical(愉悦的) islands like Hawai'i. Analyzing1 global model warming projections2 in models used by the Intergovernmental(政府间的) Panel on Climate Change, a team of scientists headed by meteorologist(气象学者) Shang-Ping Xie at the University of Hawaii at Mānoa's International Pacific Research Center, finds that ocean temperature patterns in the tropics and subtropics(亚热带) will change in ways that will lead to significant changes in rainfall patterns. The study will be published in the Journal of Climate this month, breaking ground on such regional climate forecasts.

Scientists have mostly assumed that the surfaces of Earth's oceans will warm rather evenly in the tropics. This assumption has led to "wetter-gets-wetter" and "drier-gets-drier" regional rainfall projections. Xie's team has gathered evidence that, although ocean surface temperatures can be expected to increase mostly everywhere by the middle of the century, the increase may differ by up to 1.5°C depending upon the region.

"Compared to the mean projected rise of 1°C, such differences are fairly large and can have a pronounced(断然的,显著的) impact on tropical and subtropical climate by altering atmospheric3 heating patterns and therefore rainfall," explains Xie. "Our results broadly indicate that regions of peak sea surface temperature will get wetter, and those relatively4 cool will get drier."

Two patterns stand out. First, the maximum temperature rise in the Pacific is along a broad band at the equator(赤道) . Already today the equatorial Pacific sets the rhythm of a global climate oscillation(摆动,振动) as shown by the world-wide impact of El Niño(厄尔尼诺现象) . This broad band of peak temperature on the equator changes the atmospheric heating in the models. By anchoring a rainband(雨带) similar to that during an El Nino, it influences climate around the world through atmospheric teleconnections(远程并置对比) .

A second ocean warming pattern with major impact on rainfall noted5 by Xie and his colleagues occurs in the Indian Ocean and would affect the lives of billions of people. Overlayed on Indian Ocean warming for part of the year is what scientists call the Indian Ocean Dipole that occasionally occurs today once every decade or so. Thus, the models show that warming in the western Indian Ocean is amplified6(放大,详述) , reaching 1.5°C, while the eastern Indian Ocean it is dampened(抑制,沮丧) to around 0.5°C.

"Should this pattern come about," Xie predicts, "it can be expected to dramatically shift rainfall over eastern Africa, India, and Southeast Asia. Droughts(干旱) could then beset7(困扰,围绕) Indonesia and Australia, whereas regions of India and regions of Africa bordering the Arabian Sea could get more rain than today."

Patterns of sea surface temperature warming and precipitation(坠落,沉淀) change in 2050 as compared with 2000. Annual mean precipitation change is shown in green/gray shade and white contours(等高线,轮廓) in mm/month. Precipitation tends to increase over regions with ocean warming above the tropical mean (contours of warm colors in oC), and to decrease where ocean warming is below the tropical mean (contours of cool colors).



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1 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析;分析( analyze的现在分词 );分解;解释;对…进行心理分析n.分析
参考例句:
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据,暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然,他对其预测所作的分析倒也八九不离十。 来自辞典例句
2 projections 7275a1e8ba6325ecfc03ebb61a4b9192     
预测( projection的名词复数 ); 投影; 投掷; 突起物
参考例句:
  • Their sales projections are a total thumbsuck. 他们的销售量预测纯属估计。
  • The council has revised its projections of funding requirements upwards. 地方议会调高了对资金需求的预测。
3 atmospheric 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。
4 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。
5 noted 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。
6 amplified d305c65f3ed83c07379c830f9ade119d     
放大,扩大( amplify的过去式和过去分词 ); 增强; 详述
参考例句:
  • He amplified on his remarks with drawings and figures. 他用图表详细地解释了他的话。
  • He amplified the whole course of the incident. 他详述了事件的全过程。
7 beset SWYzq     
v.镶嵌;困扰,包围
参考例句:
  • She wanted to enjoy her retirement without being beset by financial worries.她想享受退休生活而不必为金钱担忧。
  • The plan was beset with difficulties from the beginning.这项计划自开始就困难重重。
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