【雙語閱讀】氣候和太陽圈 Climate and the solar cycle.

　　為幫助廣大考生更好地準備雅思、托福、SAT等考試，澳際留學特推出【英語學習】頻道，涵蓋基礎英語、實用英語、娛樂英語等多項內容，在您通往成功的道路上做您最堅實的左膀右臂。

　　以下部分為【雙語閱讀】內容，本文介紹氣候和太陽圈，中文翻譯部分見第二頁。

　　氣候和太陽圈：不相信全球變暖是人為因素造成的和那些企圖讓別人不相信的人常常會將太陽的易變表現(xiàn)作為假設進行選擇。一項新的研究正在致力于研究歐洲的嚴冬和日漸變暖的北極圈與太陽的變化活動可能的關聯(lián)，似乎是為了證明此觀點。

　　Science and Technolgy

　　Climate and the solar cycle

　　Chilling out in the winter sun

　　Stratospheric changes can lead to nasty cold snaps

　　THOSE unconvinced-and those seeking to unconvince others-of the reality of man-made global warming often point to the changeable behaviour of the sun as an alternative hypothesis. A new study showing how the severity of winters in Europe, and warming in the Arctic, might be linked to changes in solar activity might seem to add to this case. In itself, it does not, for the heat (or, rather, the cold) in question is being redistributed, not retained. But it does point to two other lessons about climate change: that hard data on the factors which affect it are sometimes difficult to come by; and that computer models of the climate can be quite impressive tools for working out what is going on.

　　The sun&aposs activity waxes and wanes on an 11-year cycle, and over this cycle the amount of ultraviolet (UV) light the sun emits changes a lot more than does the total amount of energy. The stratosphere, the part of the Earth&aposs atmosphere which does most to absorb UV, might thus be expected to be particularly sensitive to the cycle. In a paper just published in Nature Geoscience, Sarah Ineson of Britain&aposs Meteorological Office and her colleagues compared the way that the Met Office&aposs new and putatively improved climate model dealt with winters at times of high UV and at times of low UV, using data on the amount of ultraviolet the sun gives off that were collected by a satellite called SORCE. Dr Ineson found that at low UV levels the stratosphere in the tropics was cooler, because there was less UV for it to absorb, which meant the difference in temperature between the tropical stratosphere and the polar stratosphere shrank. That changed the way the atmosphere circulated, and as those changes spread down into the lower atmosphere they made it easier for cold surface air from the Arctic to come south in winter, freezing chunks of northern Europe.

　　These conditions looked similar to those seen in the past two cold European winters-which occurred at a time of low solar activity. The Arctic itself, in models and in real life, was warmer than usual, as were parts of Canada. In contrast, northern Europe, swathes of Russia and bits of America were colder. Why had this solar fect not been seen bore? To some extent it had.

　　Earlier modelling of a period of prolonged low solar activity in the 17th and 18th centuries showed similar patterns. That models of today&aposs climate had not was, in part, because they used much lower estimates of the amount of UV variation over the solar cycle than those derived from the SORCE data, the most precise to be taken from a satellite looking at the sun. It may just be that working with more realistic data made the model work better. This does not mean the question is settled.

　　Some scientists suspect the SORCE data may be exaggerating the sun&aposs variability, and if they were revised the link might go away. There are other theories around seeking to explain the recent cold winters, too. Improving predictions of future cold winters on the basis of this work, as the researchers say they would like to do, may thus prove hard. But though global warming has made people look to models as predictors of the future, that is not their strongest suit. Something they can do much better is look at what happens when a variable such as UV is altered, compare that with the data, and thus gain insight into the mechanisms by which climate works. This new research provides a good example of what such an approach can achieve.

　　【中文對照翻譯】

　　科技

　　氣候和太陽圈

　　在冬日的陽光中發(fā)冷

　　平流層的變化能引發(fā)討人厭的寒流

　　不相信全球變暖是人為因素造成的和那些企圖讓別人不相信的人常常會將太陽的易變表現(xiàn)作為假設進行選擇。 一項新的研究正在致力于研究歐洲的嚴冬和日漸變暖的北極圈與太陽的變化活動可能的關聯(lián)，似乎是為了證明此觀點。 實則不然，因為受人質疑的太陽熱能(或者說冷能)一直在重新分布，而不是保持不變的。 但這項研究卻讓人們從氣候變化中學到了其他兩點： 影響因子的數(shù)據(jù)有時候很難得到;氣候的電腦模型能夠模擬出現(xiàn)在的氣候狀況，讓人印象深刻。

　　太陽的活動周期是11年，在此周期內太陽散發(fā)出的紫外線總量的變化比太陽能總量的變化要大的多。 吸收大部分紫外線的平流層?——地球大氣圈的一部分，在此周期內可能會變得異常敏感。 剛剛在《自然-地球科學》雜志上發(fā)表的一篇論文中，英國氣象辦公室的沙哈.伊內森和她的同事用該氣象辦公室公認的新型氣候改進模型，對其在冬天紀錄的高紫外線和低紫外線數(shù)據(jù)進行比較，這些數(shù)據(jù)是由一架名叫SORCE的衛(wèi)星收集太陽散發(fā)的紫外線量獲得的。 伊內森博士發(fā)現(xiàn)熱帶地區(qū)平流層中的紫外線含量低，因而就更涼爽， 因為那里沒有足夠的紫外線可以吸收，也就意味著熱帶地區(qū)平流層的氣溫和極地地區(qū)平流層的氣溫差異很大。 這種情況改變了大氣環(huán)流的方式。 冬天，當大氣環(huán)流變化散布到低一點的大氣中時，自北極圈表層而來的冷空氣很容易就能傳播到南方，讓北歐的大部分國家處于冰凍之中。

　　這些狀況和過去的兩次發(fā)生在歐洲的嚴冬很相似——那兩次嚴冬都發(fā)生在太陽活動頻率很低的時候。 而北極圈本身，無論是作為模型還是實際情況，都比平常要溫暖，加拿大部分地區(qū)也是如此。 臨近俄羅斯和美國的北歐則相反，顯得比平時更冰冷。 為什么我們之前沒有看出這種日光影響呢? 某種程度上，我們看到過。

　　更早以前，對17、18世紀時太陽活動持續(xù)不活躍的那段時期所做的模型也體現(xiàn)了同樣的結構。 但如今的氣候模型卻沒有體現(xiàn)出來。 部分原因是因為對太陽圈內紫外線變化量的估計比直接從SORCE中得來的要低的多，SORCE觀察太陽所得出的數(shù)據(jù)，比其他的衛(wèi)星更為精準。 那么用更為接近實際的數(shù)據(jù)做模型或許更為可靠。 這并不意味著問題解決了。

　　一些科學家懷疑SORCE的數(shù)據(jù)可能夸大了太陽的變化性，如果數(shù)據(jù)一經修改，兩者的關聯(lián)可能也不復存在了。 還有其他一些理論也正尋求解釋最近冷冬的原因。 研究員們說，他們想通過這些理論模型來改進預測未來冷冬的準確性，但看來并不那么容易。 盡管全球變暖讓人們將模型視為未來的預言者，這卻不是模型的最大作用。 它們還有更大的作用，它們能觀察當一個變量改變時(如紫外線)會發(fā)生什么，并與數(shù)據(jù)作比較，從而洞察出氣候變化的機制。 這項新的研究為這種方法所能取得的結果提供了好的例子。

　　為幫助廣大考生更好地準備雅思、托福、SAT等考試，澳際留學特推出【英語學習】頻道，涵蓋基礎英語、實用英語、娛樂英語等多項內容，在您通往成功的道路上做您最堅實的左膀右臂。

　　以下部分為【雙語閱讀】內容，本文介紹氣候和太陽圈，中文翻譯部分見第二頁。

　　氣候和太陽圈：不相信全球變暖是人為因素造成的和那些企圖讓別人不相信的人常常會將太陽的易變表現(xiàn)作為假設進行選擇。一項新的研究正在致力于研究歐洲的嚴冬和日漸變暖的北極圈與太陽的變化活動可能的關聯(lián)，似乎是為了證明此觀點。

　　Science and Technolgy

　　Climate and the solar cycle

　　Chilling out in the winter sun

　　Stratospheric changes can lead to nasty cold snaps

　　THOSE unconvinced-and those seeking to unconvince others-of the reality of man-made global warming often point to the changeable behaviour of the sun as an alternative hypothesis. A new study showing how the severity of winters in Europe, and warming in the Arctic, might be linked to changes in solar activity might seem to add to this case. In itself, it does not, for the heat (or, rather, the cold) in question is being redistributed, not retained. But it does point to two other lessons about climate change: that hard data on the factors which affect it are sometimes difficult to come by; and that computer models of the climate can be quite impressive tools for working out what is going on.

　　The sun&aposs activity waxes and wanes on an 11-year cycle, and over this cycle the amount of ultraviolet (UV) light the sun emits changes a lot more than does the total amount of energy. The stratosphere, the part of the Earth&aposs atmosphere which does most to absorb UV, might thus be expected to be particularly sensitive to the cycle. In a paper just published in Nature Geoscience, Sarah Ineson of Britain&aposs Meteorological Office and her colleagues compared the way that the Met Office&aposs new and putatively improved climate model dealt with winters at times of high UV and at times of low UV, using data on the amount of ultraviolet the sun gives off that were collected by a satellite called SORCE. Dr Ineson found that at low UV levels the stratosphere in the tropics was cooler, because there was less UV for it to absorb, which meant the difference in temperature between the tropical stratosphere and the polar stratosphere shrank. That changed the way the atmosphere circulated, and as those changes spread down into the lower atmosphere they made it easier for cold surface air from the Arctic to come south in winter, freezing chunks of northern Europe.

　　These conditions looked similar to those seen in the past two cold European winters-which occurred at a time of low solar activity. The Arctic itself, in models and in real life, was warmer than usual, as were parts of Canada. In contrast, northern Europe, swathes of Russia and bits of America were colder. Why had this solar fect not been seen bore? To some extent it had.

　　Earlier modelling of a period of prolonged low solar activity in the 17th and 18th centuries showed similar patterns. That models of today&aposs climate had not was, in part, because they used much lower estimates of the amount of UV variation over the solar cycle than those derived from the SORCE data, the most precise to be taken from a satellite looking at the sun. It may just be that working with more realistic data made the model work better. This does not mean the question is settled.

　　Some scientists suspect the SORCE data may be exaggerating the sun&aposs variability, and if they were revised the link might go away. There are other theories around seeking to explain the recent cold winters, too. Improving predictions of future cold winters on the basis of this work, as the researchers say they would like to do, may thus prove hard. But though global warming has made people look to models as predictors of the future, that is not their strongest suit. Something they can do much better is look at what happens when a variable such as UV is altered, compare that with the data, and thus gain insight into the mechanisms by which climate works. This new research provides a good example of what such an approach can achieve.

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