GRE阅读题目解析:大气成分与全球温度变化

　　P2

　　1

　　Aided by the recent ability to analyze samples of air trapped in glaciers, scientists now have a clearer idea of the relationship between atmospheric composition and global temperature change over the past 160,000 years.

　　最近，得益于科学家们已经能够分析冰川中封闭的空气样本，他们对过去 160000 年间大气成分与全球温度变化之间的关系，有了更清晰的认识。

　　2

　　In particular, determination of atmospheric composition during periods of glacial expansion and retreat (cooling and warming) is possible using data from the 2,000-meter Vostok ice core drilled in Antarctica.

　　特别是，借助位于南极洲 2000 米深处的 V 冰芯勘探数据，冰川期扩张与回缩期间(变冷与回暖)的大气成分也有望确定。

　　3

　　The technique involved is similar to that used in analyzing cores of marine sediments, where the ratio of the two common isotopes of oxygen, 18O and 16O, accurately reflects past temperature changes.

　　所使用的技术，与分析海洋沉积物内核的技术类似，其中氧的两种常见同位素， 16O 和 18O 的比例精确地反映出过去的温度变化。

　　3.5

　　Isotopic analysis of oxygen in the Vostok core suggests mean global temperature fluctuations of up to 10 degrees centigrade over the past 160,000 years.

　　对 V 冰芯的氧同位素分析结果显示，地球的平均温度在过去的 160000 年间，浮动上限是 10 摄氏度。

　　(mean 此处做形容词，中间的，平均的)

　　4

　　Data from the Vostok core also indicate that the amount of carbon dioxide has fluctuated with temperature over the same period: the higher the temperature, the higher the concentration of carbon dioxide and the lower the temperature, the lower the concentration.

　　来自 V 冰芯的数据也表明，同时期二氧化碳的数量也随温度浮动：温度越高二氧化碳浓度越高，反之亦然。

　　5

　　Although change in carbon dioxide content closely follows change in temperature during periods of deglaciation, it apparently lags behind temperature during periods of cooling.

　　尽管冰消期内，二氧化碳的比例紧跟温度变化而变化，但在冷却期，它明显滞后于温度变化。

　　(这句话仔细读，否则题目就做错。

　　deglaciation 好猜，因为 glacier 是冰川，加了 de- 肯定是冰化了，那么就是变暖的过程中，在变暖过程中二者的关系是，二氧化碳浓度变化 closely follows 升温;

　　periods of cooling 变冷的时期，你同样可以替换成 glaciation 或 glacial periods;

　　结合句首的 although，我们应该能够推测，后半句 periods of cooling 的情况下，二氧化碳的变化 doesn't follow closely，所以修饰 lags 的副词 apparently 就是 “ 明显地 ”，题目有考这一点，希望你答对。

　　)

　　6

　　The correlation of carbon dioxide with temperature, of course, does not establish whether changes in atmospheric composition caused the warming and cooling trends or were caused by them.

　　二氧化碳(浓度)与温度的关联，当然不说明大气成分变化导致了冷暖变化趋势，或被冷暖变化趋势所决定。

　　7

　　The correlation between carbon dioxide and temperature throughout the Vostok record is consistent and predictable.

　　纵观 V 记录，二氧化碳与温度的这种关联是始终的，可预测的。

　　8

　　The absolute temperature changes, however, are from 5 to 14 times greater than would be expected on the basis of carbon dioxide's own ability to absorb infrared radiation, or radiant heat.

　　然而，温度变化的绝对值，比人们预期的二氧化碳吸收红外辐射或者说辐射热所造成的升温，高出 5 到 14 倍。

　　9

　　This reaction suggests that, quite aside from changes in heat-trapping gases, commonly known as greenhouse gases, certain positive feedbacks are also amplifying the temperature change.

　　这个反应表明，除了 储热气体通常被称为温室气体 的变化，特定的正回馈也会放大温度变化。

　　(aside from = apart from 除了…以外)

　　10

　　Such feedbacks might involve ice on land and sea, clouds, or water vapor, which also absorb radiant heat.

　　这类回馈可能包括陆地与海上的冰，云，或水蒸气，它们也会吸收辐射热。

　　11

　　Other data from the Vostok core show that methane gas also correlates closely with temperature and carbon dioxide.

　　V 冰芯的其他数据显示，甲烷也与温度及二氧化碳密切相关。

　　12

　　The methane concentration nearly doubled, for example, between the peak of the penultimate glacial period and the following interglacial period.

　　例如，从倒数第二个冰期最冷的时间点到其后的间冰期，甲烷的浓度几乎翻倍。

　　(penultimate 【MWC】【pi-'nəl-tə-mət】倒数第二(的)

　　interglacial 间冰期的，间冰期是指两个冰期之间的相对较短的温暖期)

　　13

　　Within the present interglacial period it has more than doubled in just the past 300 years and is rising rapidly.

　　在当下这个间冰期，它在过去 300 年的上升已经超过了原来的两倍，且还在快速升高。

　　14

　　Although the concentration of atmospheric methane is more than two orders of magnitude lower than that of carbon dioxide, it cannot be ignored: the radiative properties of methane make it 20 times more effective, molecule for molecule, than carbon dioxide in absorbing radiant heat.

　　尽管大气中甲烷浓度的数量级，比二氧化碳低两个量级还多，但不能忽略：单个分子比较来看，甲烷的辐射特性，导致它吸收辐射热的效率是二氧化碳的 20 倍。

　　(order of magnitude 【MWC】a range of magnitude extending from some value to ten times that value。数量级，某一数值所属的 10 的 X 次方的大概范围，比如你的体重的量级是 10 的 1 次方千克，也就是几十千克，某些胖子的体重量级可能达到 10 的 2 次方千克，因为超过一百千克了，地球质量的量级可能是 10 的 25 次方千克。量级是用来大概衡量一个数值范围的表述。)

　　15

　　On the basis of a simulation model that climatological researchers have developed, methane appears to have been about 25 percent as important as carbon dioxide in the warming that took place during the most recent glacial retreat 8,000 to 10,000 years ago. (445 words)

　　在一个模拟模型的帮助下，气象学研究者们已经发现，在上一个冰川回撤期，距今约 8000 到 10000 年前，甲烷大约提供了相当于二氧化碳 25% 的暖化贡献。

　　For the following question, consider each of the choices separately and select all that apply

　　3. The passage provides information to support which of the following statements about methane EXCEPT?

　　(A) Methane is more effective than carbon dioxide in absorbing radiant heat.

　　(B) The higher the concentration of carbon dioxide in the Earth's atmosphere; the lower the concentration of methane.

　　(C) Most of the global warming that has occurred during the past 10 years has been associated with increased methane concentration.

　　选 BC

　　关于甲烷，哪项文中没有信息支持：

　　A 有支持，不选。句 14 。

　　B 正确项。大气中二氧化碳浓度越高，甲烷的浓度越低。这个表述是错误的，句 11-13 告诉我们，变暖的过程中，二氧化碳和甲烷的浓度都升高。错误信息文章显然没有信息支持，所以选。

　　C 正确项。准确地说，我们缺乏必要信息，文中找不到关于最近 10 年的信息可供判断。

　　4. According to the passage, which of the following statements best describes the relationship between carbon dioxide and global temperature?

　　(A) Carbon dioxide levels change immediately in response to changes in temperature.

　　(B) Carbon dioxide levels correlate with global temperature during cooling periods only.

　　(C) Once carbon dioxide levels increase, they remain high regardless of changes in global temperature.

　　(D)Carbon dioxide levels increase more quickly than global temperature does.

　　(E) During cooling periods, carbon dioxide levels initially remain high and then decline.

　　选 E

　　句 5 已经解释的比较清楚，不再赘述。

　　Although change in carbon dioxide content closely follows change in temperature during periods of deglaciation, it apparently lags behind temperature during periods of cooling.

　　尽管冰消期内，二氧化碳的比例紧跟温度变化而变化，但在冷却期，它明显滞后于温度变化。

　　(这句话仔细读，否则题目就做错。

　　deglaciation 好猜，因为 glacier 是冰川，加了 de- 肯定是冰化了，那么就是变暖的过程中，在变暖过程中二者的关系是，二氧化碳浓度变化 closely follows 升温;

　　periods of cooling 变冷的时期，你同样可以替换成 glaciation 或 glacial periods;

　　结合句首的 although，我们应该能够推测，后半句 periods of cooling 的情况下，二氧化碳的变化 doesn't follow closely，所以修饰 lags 的副词 apparently 就是 “ 明显地 ”，题目有考这一点，希望你答对。

　　)

　　5. It can be inferred from the passage that a long-term decrease in the concentration of carbon dioxide in the Earth's atmosphere would

　　(A) increase methane concentration in the Earth's atmosphere

　　(B) accompany a period of glaciation

　　(C) encourage the formation of more oxygen isotopes in the Earth's atmosphere

　　(D) promote the formation of more water in the Earth's global environment

　　(E) increase the amount of infrared radiation absorbed by the Earth's atmosphere

　　选 B

　　相对简单，长期看，二氧化碳浓度下降，伴随着温度下降，等于说正在进入一个冰期。

　　根据在句 4：

　　Data from the Vostok core also indicate that the amount of carbon dioxide has fluctuated with temperature over the same period: the higher the temperature, the higher the concentration of carbon dioxide and the lower the temperature, the lower the concentration.

　　和句 7：

　　The correlation between carbon dioxide and temperature throughout the Vostok record is consistent and predictable.

　　6. The passage suggests that when the methane concentration in the Earth's atmosphere decreases, which of the following also happens?

　　(A) Glaciers melt faster.

　　(B) The concentration of carbon dioxide increases.

　　(C) The mean global temperature decreases.

　　(D) Carbon dioxide absorbs more radiant beat

　　(E) More clouds form in the Earth's atmosphere

　　选 C

　　根据句 11：

　　Other data from the Vostok core show that methane gas also correlates closely with temperature and carbon dioxide.

　　甲烷和二氧化碳、温度也有相关性，后文我们又知道，甲烷也是暖化的贡献者，作用的性质与二氧化碳相同，所以选 C 。

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