Text 1
The recent, apparently successful, prediction by mathematical models of an appearance of El Nino—the warm ocean current that periodically develops along the Pacific coast of South America—has excited researchers. Jacob Berknes pointed out over 20 years ago how winds might create either abnormally warm or abnormally cold water in the eastern equatorial Pacific. 1) Nevertheless, until the development of the models no one could explain why conditions should regularly shift from one to the other, as happens in the periodic changes between appearances of the warm El Nino and the cold socalled antiEl Nino. The answer, at least if the current model that links the behavior of the ocean to that of the atmosphere is correct, is to be found in the ocean.
2) It has long been known that during an El Nino, two conditions exist: A) unusually warm water extends along the eastern Pacific, principally along the coasts of Ecuador and Peru, and B) winds blow from the west into the warmer air rising over the warm water in the east. These winds tend to create a feedback mechanism by driving the warmer surface water into “piles” that block the normal rising of deeper, cold water in the east and further warm the eastern water, thus strengthening the wind. The contribution of the model is to show that the winds of an El Nino, which raise sea level in the east, simultaneously send a signal to the west lowering sea level. According to the model, that signal is generated as a negative Rossby wave, a wave of depressed sea level, that moves westward parallel to the equator at 25 to 85 kilometers per day. 3) Taking months to travel across the Pacific, Rossby waves march to the western boundary of the Pacific basin, which is modeled as a smooth wall but in reality consists of quite irregular island chains, such as the Philippines and Indonesia.
When the waves meet the western boundary, they are reflected, and the model predicts that Rossby waves will be broken into numerous coastal Kelvin waves carrying the same negative sealevel signal. These eventually shoot toward the equator, and then head eastward along the equator propelled by the rotation of the Earth at a speed of about 250 kilometers per day. When Kelvin waves of sufficient amplitude arrive from the western Pacific, their negative sealevel signal overcomes the feedback mechanism tending to raise the sea level, and they begin to drive the system into the opposite cold mode. This produces a gradual shift in winds, one that will eventually send Rossby waves westward, waves that will eventually return as cold cycleending Kelvin waves, beginning another warming cycle.
1 It was not until the appearance of mathematical models that
[A] El Nino was defined as unusually warm or cold ocean currents.
[B] the occurrences of E1 Nino were inaccurately predicted.
[C] the cause of regular El Nino was correctly interpreted.
[D] the shifts in ocean currents were linked to atmospheric conditions.
2 Which of the following best describes the organization of the first paragraph?
[A] A model is described and its value assessed.
[B] A result is reported and its importance explained.
[C] A phenomenon is noted and its significance debated.
[D] A hypothesis is introduced and contrary evidence presented.
3 According to the model, which of the following signals the disappearance of an E1 Nino?
[A] The arrival in the eastern Pacific of negative Kelvin waves.
[B] A shift in the direction of the winds produced by an antiEl Nino.
[C] The reflection of Kelvin waves reaching the eastern border of the Pacific.
[D] An increase in the speed at which negative Rossby waves cross the Pacific.
4 Which of the following would most seriously undermine the validity of the model?
[A] El Nino extends much farther along the coasts of Ecuador and Peru during some years.
[B] The rising of cold water in the eastern Pacific depends on the local characters.
[C] The variations in the time for Rossby waves to cross the Pacific rely on the wind power.
[D] The Pacific irregular western coast hinders most Kelvin waves from heading eastward.
5 The primary purpose of the text as a whole is to
[A] introduce a new explanation of physical phenomenon.
[B] explain the difference between two natural phenomena.
[C] illustrate the limits of applying mathematics to complex problems.
[D] clarify the distinction between an old explanation and a new model.
難句突破
1 Nevertheless, until the development of the models no one could explain why conditions should regularly shift from one to the other, as happens in the periodic changes between appearances of the warm El Nino and the cold socalled antiEl Nino.
【解析】本句話的主干是“no one could explain why...”。until引導(dǎo)的短語作狀語;why引導(dǎo)的是賓語從句;as引導(dǎo)的是非限定性定語從句，修飾前面的句子。periodic應(yīng)譯成“周期性的”;appearance應(yīng)譯成“發(fā)生”。
2 It has long been known that during an El Nino, two conditions exist: A) unusually warm water extends along the eastern Pacific, principally along the coasts of Ecuador and Peru, and B) winds blow from the west into the warmer air rising over the warm water in the east.
【解析】本句話的主干是“It has long been known that...”。it是形式主語，真正的主語是后面的that引導(dǎo)的從句;冒號后面的句子是在解釋前面的句子，其中的principally along the coasts of Ecuador and Peru是插入語，rising over...短語修飾air。
3 Taking months to travel across the Pacific, Rossby waves march to the western boundary of the Pacific basin, which is modeled as a smooth wall but in reality consists of quite irregular island chains, such as the Philippines and Indonesia.
【解析】本句話的主干是“Rossby waves march to the western boundary...”。Taking months...短語作狀語;which引導(dǎo)的非限定性定語從句修飾Pacific basin，其中的such as短語是在舉例說明前面的內(nèi)容。Rossby wave應(yīng)譯成“羅斯比波浪”;march to應(yīng)譯成“來到”;island chain應(yīng)譯成“島嶼群”。
試題解析
1 直到數(shù)學(xué)模式的出現(xiàn)，
[A] 厄爾尼諾現(xiàn)象才被定義為異常的海洋暖流或冷流。
[B] 厄爾尼諾現(xiàn)象的發(fā)生才沒有得到準(zhǔn)確預(yù)測。
[C] 出現(xiàn)周期性厄爾尼諾現(xiàn)象的原因才得到正確解釋。
[D] 洋流的變化才與大氣狀況有關(guān)。【C】
【解析】細(xì)節(jié)題。題干中的“until the appearance of mathematical models”出自文章第一段第三句話中(文中用的是“until the development of the models”)，表明本題與第一段有關(guān)。第一段提到，直到這些數(shù)學(xué)模式發(fā)展出來為止，沒有人能夠解釋為什么這些狀況有規(guī)律地從一種向另一種變化，正如在暖厄爾尼諾現(xiàn)象和冷厄爾尼諾現(xiàn)象的發(fā)生期間出現(xiàn)周期性的變化一樣。這說明，數(shù)學(xué)模式的出現(xiàn)解釋了厄爾尼諾現(xiàn)象的原因。C與此意符合，為正確答案。B與此意相反;A是針對該段第二句話設(shè)置的干擾項(xiàng)，這是指雅格布·博克尼斯的發(fā)現(xiàn)，與題目的要求不符;D是針對該段最后一句話設(shè)置的干擾項(xiàng)，與文意不符合。
2 下面哪項(xiàng)最恰當(dāng)?shù)孛枋隽说谝欢蔚慕Y(jié)構(gòu)?
[A] 描述了一個(gè)模式，評估了其價(jià)值。
[B]報(bào)道了一個(gè)結(jié)果，解釋了其重要性。
[C] 說明了一種現(xiàn)象，辯論了其重要性。
[D]介紹了一種假設(shè)，提出了相反的證據(jù)?！綛】
【解析】結(jié)構(gòu)題。第一段首先提到，利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象的發(fā)生進(jìn)行的預(yù)測成功了，這次預(yù)測鼓舞了研究人員，接著介紹了該模式提出的重要意義。這說明，第一段是介紹了一項(xiàng)研究結(jié)果及其重要意義。B與此意符合，為正確答案。A不準(zhǔn)確，因?yàn)榈谝欢沃胁]有描述數(shù)學(xué)模式;C和D是誤解了第一段的結(jié)構(gòu)。
3 根據(jù)模式，下面哪項(xiàng)表示厄爾尼諾現(xiàn)象的消失?
[A] 起反作用的“開氏波浪”到達(dá)太平洋東部。
[B] 由反厄爾尼諾現(xiàn)象產(chǎn)生的風(fēng)向的改變。
[C] 到達(dá)太平洋東海岸的“開氏波浪”的折回。
[D] 穿越太平洋的、起反作用的“羅斯比波浪”速度的增加。【C】
【解析】細(xì)節(jié)題。第二段介紹了厄爾尼諾現(xiàn)象存在的兩種現(xiàn)象——異常的暖流沿著太平洋東海岸延伸、從西方來的季風(fēng)吹進(jìn)在東方暖流中產(chǎn)生的更暖的空氣中，第三段指出，如果從西部來的“開氏波浪”達(dá)到足夠的量，它們就會克服提升海平面的反饋機(jī)制，促使該機(jī)制變成相反的寒冷模式，進(jìn)而導(dǎo)致季風(fēng)的逐漸轉(zhuǎn)變，最終促使“羅斯比波浪”向西流動(dòng)，作為寒冷的、結(jié)束循環(huán)的“開氏波浪”返回，開始另一個(gè)暖流循環(huán)。這說明，“開氏波浪”的返回就預(yù)示著厄爾尼諾現(xiàn)象的結(jié)束。C與此意符合，為正確答案。A、B和D都是厄爾尼諾現(xiàn)象產(chǎn)生的跡象，與題目的要求不符。
4 下面哪項(xiàng)可能最嚴(yán)重地影響模式的正確性?
[A]在某些年份，厄爾尼諾現(xiàn)象沿厄瓜多爾和秘魯?shù)暮０堆由爝h(yuǎn)得多。
[B] 太平洋東部冷水的上升取決于當(dāng)?shù)氐奶卣鳌?BR> [C] “羅斯比波浪”穿越太平洋時(shí)間上的變化取決于風(fēng)勢。
[D]太平洋不規(guī)律的西部海岸阻礙了大多數(shù)“開氏波浪”流向東部?！綝】
【解析】細(xì)節(jié)題。第二段中間部分介紹了數(shù)學(xué)模式，隨后指出，花費(fèi)數(shù)月時(shí)間穿越太平洋后，“羅斯比波波浪”來到太平洋盆地的西部邊緣——該盆地被模擬成平坦的屏障，但實(shí)際上包含很不規(guī)則的島嶼群。這說明，該模式依據(jù)的是太平洋盆地的西部邊緣是平坦的，而如果不是這樣，則該模式就不正確。D與此意符合，為正確答案。A和B屬于無中生有;C是針對第二段最后一句話設(shè)置的干擾項(xiàng)，屬于張冠李戴，錯(cuò)把“羅斯比波浪”當(dāng)作“開氏波浪”。
5 總體上，本文的主要目的是
[A] 介紹對自然現(xiàn)象的一種新解釋。
[B]解釋兩種自然現(xiàn)象的差異。
[C] 闡明應(yīng)用數(shù)學(xué)解決復(fù)雜問題的局限性。
[D]澄清一種陳舊解釋與新模式之間的區(qū)別。【A】
【解析】主旨題。第一段提到了利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象的發(fā)生進(jìn)行的預(yù)測，接著介紹了該模式的重要性，隨后的段落具體介紹了該模式的觀點(diǎn)。這說明，本文主要是在介紹一種對厄爾尼諾現(xiàn)象的新解釋。A與此意符合，可以表達(dá)本文的主要目的，為正確答案。B只是文中提到的細(xì)節(jié)，不能表達(dá)本文的主要目的;C和D屬于無中生有。
全文譯文
最近，利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象——周期性地沿南美太平洋沿岸產(chǎn)生的暖洋流——的發(fā)生進(jìn)行了顯然是成功的預(yù)測，這次預(yù)測鼓舞了研究人員。雅格布·博克尼斯20年前就說明了季風(fēng)如何可能在太平洋赤道東部產(chǎn)生反常的暖流或反常的冷流。1)不過，直到這些數(shù)學(xué)模式發(fā)展出來為止，沒有人能夠解釋為什么這些狀況有規(guī)律地從一種向另一種變化，正如在暖厄爾尼諾現(xiàn)象和冷厄爾尼諾現(xiàn)象(所謂的反厄爾尼諾現(xiàn)象)的發(fā)生期間出現(xiàn)周期性的變化一樣。答案有可能在海洋中發(fā)現(xiàn)，至少如果目前把海洋的活動(dòng)與大氣的活動(dòng)聯(lián)系起來的模式是正確的話。
2)人們早就知道，在厄爾尼諾現(xiàn)象發(fā)生期間，存在兩種現(xiàn)象——A.異常的暖流沿著太平洋東海岸延伸，尤其是沿著厄瓜多爾和秘魯?shù)暮０堆由?，B.從西方來的季風(fēng)吹進(jìn)在東方暖流中產(chǎn)生的更暖的空氣中。通過驅(qū)使更暖的表層水變成“浪濤”，這些季風(fēng)往往形成一種反饋機(jī)制——這些浪濤妨礙了東部更深層冷水的正常上升，進(jìn)一步溫暖了東部的水域，從而加強(qiáng)了風(fēng)勢。該模式的提出就是為了表示，源于東部海平面的厄爾尼諾季風(fēng)同時(shí)向西部發(fā)出了降低海平面的信號。根據(jù)該模式，那個(gè)信號的產(chǎn)生就是低于海平面的“羅斯比波浪”(一種低于海平面的波浪)的出現(xiàn)，這種波浪以每天25千米到85千米的速度向西平行移到赤道。3)花費(fèi)數(shù)月時(shí)間穿越太平洋后，“羅斯比波浪”來到太平洋盆地的西部邊緣——該盆地被模擬成平坦的屏障，但實(shí)際上包含很不規(guī)則的島嶼群，比如菲律賓群島和印度尼西亞群島。
當(dāng)波浪遇到盆地的西部邊緣時(shí)，它們就折回，該模式預(yù)測，“羅斯比波浪”將被分解成無數(shù)沿?！伴_氏波浪”，這些波浪攜帶相同的低于海平面的信號。這些波浪最終會折回到赤道，然后，由于地球自轉(zhuǎn)的驅(qū)動(dòng)，以每天250千米的速度沿著赤道向東流動(dòng)。如果從西部來的“開氏波浪”達(dá)到足夠的量，它們低于的海平面信號就會克服往往提升海平面的反饋機(jī)制，開始促使該機(jī)制變成相反的寒冷模式。這就導(dǎo)致季風(fēng)的逐漸轉(zhuǎn)變，最終將促使“羅斯比波浪”向西流動(dòng)，這些波浪最終將作為寒冷的、結(jié)束循環(huán)的“開氏波浪”返回，又開始另一個(gè)暖流循環(huán)。
The recent, apparently successful, prediction by mathematical models of an appearance of El Nino—the warm ocean current that periodically develops along the Pacific coast of South America—has excited researchers. Jacob Berknes pointed out over 20 years ago how winds might create either abnormally warm or abnormally cold water in the eastern equatorial Pacific. 1) Nevertheless, until the development of the models no one could explain why conditions should regularly shift from one to the other, as happens in the periodic changes between appearances of the warm El Nino and the cold socalled antiEl Nino. The answer, at least if the current model that links the behavior of the ocean to that of the atmosphere is correct, is to be found in the ocean.
2) It has long been known that during an El Nino, two conditions exist: A) unusually warm water extends along the eastern Pacific, principally along the coasts of Ecuador and Peru, and B) winds blow from the west into the warmer air rising over the warm water in the east. These winds tend to create a feedback mechanism by driving the warmer surface water into “piles” that block the normal rising of deeper, cold water in the east and further warm the eastern water, thus strengthening the wind. The contribution of the model is to show that the winds of an El Nino, which raise sea level in the east, simultaneously send a signal to the west lowering sea level. According to the model, that signal is generated as a negative Rossby wave, a wave of depressed sea level, that moves westward parallel to the equator at 25 to 85 kilometers per day. 3) Taking months to travel across the Pacific, Rossby waves march to the western boundary of the Pacific basin, which is modeled as a smooth wall but in reality consists of quite irregular island chains, such as the Philippines and Indonesia.
When the waves meet the western boundary, they are reflected, and the model predicts that Rossby waves will be broken into numerous coastal Kelvin waves carrying the same negative sealevel signal. These eventually shoot toward the equator, and then head eastward along the equator propelled by the rotation of the Earth at a speed of about 250 kilometers per day. When Kelvin waves of sufficient amplitude arrive from the western Pacific, their negative sealevel signal overcomes the feedback mechanism tending to raise the sea level, and they begin to drive the system into the opposite cold mode. This produces a gradual shift in winds, one that will eventually send Rossby waves westward, waves that will eventually return as cold cycleending Kelvin waves, beginning another warming cycle.
1 It was not until the appearance of mathematical models that
[A] El Nino was defined as unusually warm or cold ocean currents.
[B] the occurrences of E1 Nino were inaccurately predicted.
[C] the cause of regular El Nino was correctly interpreted.
[D] the shifts in ocean currents were linked to atmospheric conditions.
2 Which of the following best describes the organization of the first paragraph?
[A] A model is described and its value assessed.
[B] A result is reported and its importance explained.
[C] A phenomenon is noted and its significance debated.
[D] A hypothesis is introduced and contrary evidence presented.
3 According to the model, which of the following signals the disappearance of an E1 Nino?
[A] The arrival in the eastern Pacific of negative Kelvin waves.
[B] A shift in the direction of the winds produced by an antiEl Nino.
[C] The reflection of Kelvin waves reaching the eastern border of the Pacific.
[D] An increase in the speed at which negative Rossby waves cross the Pacific.
4 Which of the following would most seriously undermine the validity of the model?
[A] El Nino extends much farther along the coasts of Ecuador and Peru during some years.
[B] The rising of cold water in the eastern Pacific depends on the local characters.
[C] The variations in the time for Rossby waves to cross the Pacific rely on the wind power.
[D] The Pacific irregular western coast hinders most Kelvin waves from heading eastward.
5 The primary purpose of the text as a whole is to
[A] introduce a new explanation of physical phenomenon.
[B] explain the difference between two natural phenomena.
[C] illustrate the limits of applying mathematics to complex problems.
[D] clarify the distinction between an old explanation and a new model.
難句突破
1 Nevertheless, until the development of the models no one could explain why conditions should regularly shift from one to the other, as happens in the periodic changes between appearances of the warm El Nino and the cold socalled antiEl Nino.
【解析】本句話的主干是“no one could explain why...”。until引導(dǎo)的短語作狀語;why引導(dǎo)的是賓語從句;as引導(dǎo)的是非限定性定語從句，修飾前面的句子。periodic應(yīng)譯成“周期性的”;appearance應(yīng)譯成“發(fā)生”。
2 It has long been known that during an El Nino, two conditions exist: A) unusually warm water extends along the eastern Pacific, principally along the coasts of Ecuador and Peru, and B) winds blow from the west into the warmer air rising over the warm water in the east.
【解析】本句話的主干是“It has long been known that...”。it是形式主語，真正的主語是后面的that引導(dǎo)的從句;冒號后面的句子是在解釋前面的句子，其中的principally along the coasts of Ecuador and Peru是插入語，rising over...短語修飾air。
3 Taking months to travel across the Pacific, Rossby waves march to the western boundary of the Pacific basin, which is modeled as a smooth wall but in reality consists of quite irregular island chains, such as the Philippines and Indonesia.
【解析】本句話的主干是“Rossby waves march to the western boundary...”。Taking months...短語作狀語;which引導(dǎo)的非限定性定語從句修飾Pacific basin，其中的such as短語是在舉例說明前面的內(nèi)容。Rossby wave應(yīng)譯成“羅斯比波浪”;march to應(yīng)譯成“來到”;island chain應(yīng)譯成“島嶼群”。
試題解析
1 直到數(shù)學(xué)模式的出現(xiàn)，
[A] 厄爾尼諾現(xiàn)象才被定義為異常的海洋暖流或冷流。
[B] 厄爾尼諾現(xiàn)象的發(fā)生才沒有得到準(zhǔn)確預(yù)測。
[C] 出現(xiàn)周期性厄爾尼諾現(xiàn)象的原因才得到正確解釋。
[D] 洋流的變化才與大氣狀況有關(guān)。【C】
【解析】細(xì)節(jié)題。題干中的“until the appearance of mathematical models”出自文章第一段第三句話中(文中用的是“until the development of the models”)，表明本題與第一段有關(guān)。第一段提到，直到這些數(shù)學(xué)模式發(fā)展出來為止，沒有人能夠解釋為什么這些狀況有規(guī)律地從一種向另一種變化，正如在暖厄爾尼諾現(xiàn)象和冷厄爾尼諾現(xiàn)象的發(fā)生期間出現(xiàn)周期性的變化一樣。這說明，數(shù)學(xué)模式的出現(xiàn)解釋了厄爾尼諾現(xiàn)象的原因。C與此意符合，為正確答案。B與此意相反;A是針對該段第二句話設(shè)置的干擾項(xiàng)，這是指雅格布·博克尼斯的發(fā)現(xiàn)，與題目的要求不符;D是針對該段最后一句話設(shè)置的干擾項(xiàng)，與文意不符合。
2 下面哪項(xiàng)最恰當(dāng)?shù)孛枋隽说谝欢蔚慕Y(jié)構(gòu)?
[A] 描述了一個(gè)模式，評估了其價(jià)值。
[B]報(bào)道了一個(gè)結(jié)果，解釋了其重要性。
[C] 說明了一種現(xiàn)象，辯論了其重要性。
[D]介紹了一種假設(shè)，提出了相反的證據(jù)?！綛】
【解析】結(jié)構(gòu)題。第一段首先提到，利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象的發(fā)生進(jìn)行的預(yù)測成功了，這次預(yù)測鼓舞了研究人員，接著介紹了該模式提出的重要意義。這說明，第一段是介紹了一項(xiàng)研究結(jié)果及其重要意義。B與此意符合，為正確答案。A不準(zhǔn)確，因?yàn)榈谝欢沃胁]有描述數(shù)學(xué)模式;C和D是誤解了第一段的結(jié)構(gòu)。
3 根據(jù)模式，下面哪項(xiàng)表示厄爾尼諾現(xiàn)象的消失?
[A] 起反作用的“開氏波浪”到達(dá)太平洋東部。
[B] 由反厄爾尼諾現(xiàn)象產(chǎn)生的風(fēng)向的改變。
[C] 到達(dá)太平洋東海岸的“開氏波浪”的折回。
[D] 穿越太平洋的、起反作用的“羅斯比波浪”速度的增加。【C】
【解析】細(xì)節(jié)題。第二段介紹了厄爾尼諾現(xiàn)象存在的兩種現(xiàn)象——異常的暖流沿著太平洋東海岸延伸、從西方來的季風(fēng)吹進(jìn)在東方暖流中產(chǎn)生的更暖的空氣中，第三段指出，如果從西部來的“開氏波浪”達(dá)到足夠的量，它們就會克服提升海平面的反饋機(jī)制，促使該機(jī)制變成相反的寒冷模式，進(jìn)而導(dǎo)致季風(fēng)的逐漸轉(zhuǎn)變，最終促使“羅斯比波浪”向西流動(dòng)，作為寒冷的、結(jié)束循環(huán)的“開氏波浪”返回，開始另一個(gè)暖流循環(huán)。這說明，“開氏波浪”的返回就預(yù)示著厄爾尼諾現(xiàn)象的結(jié)束。C與此意符合，為正確答案。A、B和D都是厄爾尼諾現(xiàn)象產(chǎn)生的跡象，與題目的要求不符。
4 下面哪項(xiàng)可能最嚴(yán)重地影響模式的正確性?
[A]在某些年份，厄爾尼諾現(xiàn)象沿厄瓜多爾和秘魯?shù)暮０堆由爝h(yuǎn)得多。
[B] 太平洋東部冷水的上升取決于當(dāng)?shù)氐奶卣鳌?BR> [C] “羅斯比波浪”穿越太平洋時(shí)間上的變化取決于風(fēng)勢。
[D]太平洋不規(guī)律的西部海岸阻礙了大多數(shù)“開氏波浪”流向東部?！綝】
【解析】細(xì)節(jié)題。第二段中間部分介紹了數(shù)學(xué)模式，隨后指出，花費(fèi)數(shù)月時(shí)間穿越太平洋后，“羅斯比波波浪”來到太平洋盆地的西部邊緣——該盆地被模擬成平坦的屏障，但實(shí)際上包含很不規(guī)則的島嶼群。這說明，該模式依據(jù)的是太平洋盆地的西部邊緣是平坦的，而如果不是這樣，則該模式就不正確。D與此意符合，為正確答案。A和B屬于無中生有;C是針對第二段最后一句話設(shè)置的干擾項(xiàng)，屬于張冠李戴，錯(cuò)把“羅斯比波浪”當(dāng)作“開氏波浪”。
5 總體上，本文的主要目的是
[A] 介紹對自然現(xiàn)象的一種新解釋。
[B]解釋兩種自然現(xiàn)象的差異。
[C] 闡明應(yīng)用數(shù)學(xué)解決復(fù)雜問題的局限性。
[D]澄清一種陳舊解釋與新模式之間的區(qū)別。【A】
【解析】主旨題。第一段提到了利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象的發(fā)生進(jìn)行的預(yù)測，接著介紹了該模式的重要性，隨后的段落具體介紹了該模式的觀點(diǎn)。這說明，本文主要是在介紹一種對厄爾尼諾現(xiàn)象的新解釋。A與此意符合，可以表達(dá)本文的主要目的，為正確答案。B只是文中提到的細(xì)節(jié)，不能表達(dá)本文的主要目的;C和D屬于無中生有。
全文譯文
最近，利用數(shù)學(xué)模式對厄爾尼諾現(xiàn)象——周期性地沿南美太平洋沿岸產(chǎn)生的暖洋流——的發(fā)生進(jìn)行了顯然是成功的預(yù)測，這次預(yù)測鼓舞了研究人員。雅格布·博克尼斯20年前就說明了季風(fēng)如何可能在太平洋赤道東部產(chǎn)生反常的暖流或反常的冷流。1)不過，直到這些數(shù)學(xué)模式發(fā)展出來為止，沒有人能夠解釋為什么這些狀況有規(guī)律地從一種向另一種變化，正如在暖厄爾尼諾現(xiàn)象和冷厄爾尼諾現(xiàn)象(所謂的反厄爾尼諾現(xiàn)象)的發(fā)生期間出現(xiàn)周期性的變化一樣。答案有可能在海洋中發(fā)現(xiàn)，至少如果目前把海洋的活動(dòng)與大氣的活動(dòng)聯(lián)系起來的模式是正確的話。
2)人們早就知道，在厄爾尼諾現(xiàn)象發(fā)生期間，存在兩種現(xiàn)象——A.異常的暖流沿著太平洋東海岸延伸，尤其是沿著厄瓜多爾和秘魯?shù)暮０堆由?，B.從西方來的季風(fēng)吹進(jìn)在東方暖流中產(chǎn)生的更暖的空氣中。通過驅(qū)使更暖的表層水變成“浪濤”，這些季風(fēng)往往形成一種反饋機(jī)制——這些浪濤妨礙了東部更深層冷水的正常上升，進(jìn)一步溫暖了東部的水域，從而加強(qiáng)了風(fēng)勢。該模式的提出就是為了表示，源于東部海平面的厄爾尼諾季風(fēng)同時(shí)向西部發(fā)出了降低海平面的信號。根據(jù)該模式，那個(gè)信號的產(chǎn)生就是低于海平面的“羅斯比波浪”(一種低于海平面的波浪)的出現(xiàn)，這種波浪以每天25千米到85千米的速度向西平行移到赤道。3)花費(fèi)數(shù)月時(shí)間穿越太平洋后，“羅斯比波浪”來到太平洋盆地的西部邊緣——該盆地被模擬成平坦的屏障，但實(shí)際上包含很不規(guī)則的島嶼群，比如菲律賓群島和印度尼西亞群島。
當(dāng)波浪遇到盆地的西部邊緣時(shí)，它們就折回，該模式預(yù)測，“羅斯比波浪”將被分解成無數(shù)沿?！伴_氏波浪”，這些波浪攜帶相同的低于海平面的信號。這些波浪最終會折回到赤道，然后，由于地球自轉(zhuǎn)的驅(qū)動(dòng)，以每天250千米的速度沿著赤道向東流動(dòng)。如果從西部來的“開氏波浪”達(dá)到足夠的量，它們低于的海平面信號就會克服往往提升海平面的反饋機(jī)制，開始促使該機(jī)制變成相反的寒冷模式。這就導(dǎo)致季風(fēng)的逐漸轉(zhuǎn)變，最終將促使“羅斯比波浪”向西流動(dòng)，這些波浪最終將作為寒冷的、結(jié)束循環(huán)的“開氏波浪”返回，又開始另一個(gè)暖流循環(huán)。