GMAT申友阅读RC题库-The passage provides information to support which of the following statements about the occurrence of very cold winters in the-破解版08-真题答案解析

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RC33-35篇

Since the 1850s researchers have tried to show that variations in seasonal weather are connected in some ways with sunspots

, the outward sign of an increase in the Sun's activity. However, sciences lacked evidence supporting such a link until the mid-1980s, when van Loon and Labitzke compiled statistical evidence suggesting that a link exists and that it involves winds in the upper atmosphere above the equator which reverse their direction from east to west or west to east, every twelve to fifteen months. This phenomenon is called the quasi-biennial oscillation (QBO), and although meteorologists have known about the QBO since the 1950s, until the 1980s no one recognized a subtle but statistically significant link between the QBO and certain pattern of weather. When the west to east direction of winds in the upper atmosphere coincides with periods of high solar activity that occur approximately every eleven years, winters in the eastern and central United States are very cold.

On this basis, some meteorologists predicted that the winter of 1988-1989 in the United States would be severe. However, the winter was a mild one overall, and the meteorologists' attempt to make the connection between the Sun and weather on the Earth appeared unsuccessful, until Barston and Liverzey proposed a hypothesis explaining why the prediction had failed. They argued that the prediction had not taken into account another important element in the climate: the more or less regular pattern of fluctuations in the temperature of the surface waters of the tropical Pacific Ocean.

Barston and Livezey noted that when the water temperature is abnormally high-the phenomenon called EL Nino—the changes of cold winter weather over North American increase. The opposite situation, when surface temperatures are well below normal—La Nina—is far less common. In fact, until late 1988 no one had seen the combination of La Nina, westerly winds in the upper atmosphere, and high solar activity.

Thus, according to Barston and Livezey, La Nina cancelled out the effect of the other two climatic factors and caused the mild winter of 1988-1989. Although this hypothesis is plausible, much research remains to be done before meteorologists can establish and explain the effects of increased solar activity on seasonal weather changes.

The passage provides information to support which of the following

statements about the occurrence of very cold winters in the eastern and central United States.

A. Such winter are most likely to occur if the winds in the winds in the upper atmosphere over the equator blow from the east rather than from the west.
B. Such winters are most likely to occur if increased activity of the Sun coincides with the appearance of La Nina.
C. Such winters are less likely to occur if increased activity of the Sun coincides with the appearance of El Nino.
D. Such winters are less likely to occur if there is an increase in the number of sunspots on the surface of the Sun.

E. Such winters are less likely to occur if there is a drop in the temperature of the surface waters of the tropical Pacific Ocean.

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整篇文章就

提到了3种factor去影响气候温度 sun activity和赤道上方的wind direction两种因素一起影响气候温度是文章一开始就提出的一种假设，说是当方向从W→E，而且刚好遇上太阳活动高峰期，美国中部和东部的冬天就会非常冷。第三个因素是个这个假设预测1988-1989年美国冬天将会非常严寒失败之后，由B、L提出的一个新的因素，这个因素是the temperature of the surface waters of the tropical Pacific Ocean.，当这里的温度比正常的高，这种现象叫 EL Nino, 那么north america的冬天就会很冷;相反的现象叫La Nina，比起EL Nino，它更难得。文章并没有把Sun activity或者wind direction和temperature联系起来，排除BC 单独Sun activit或者wind direction也不能决定气候情况，排除AD 选项E 定位到倒数第二段第一句和第二句，正确。