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　　Climate and Urban Development

　　For more than a hundred years,it has been known that cities are generally warmer than surrounding rural areas.This region of city warmth,known as the urban heat island,can influence the concentration of air pollution.However,before we look at its influence,let’s see how the heat island actually forms.

　　The urban heat island is due to industrial and urban development.In rural areas,a large part of the incoming solar energy is used in evaporating water from vegetation and soil.In cities,where less vegetation and exposed soil exist,the majority of the Sun’s energy is absorbed by urban structures and asphalt.Hence,during warm daylight hours,less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.The cause of the urban heat island is quite involved.Depending on the location,time of year,and time of day,any or all of the following differences between cities and their surroundings can be important:albedo(reflectivity of the surface),surface roughness,emissions of heat,emissions of moisture,and emissions of particles that affect net radiation and the growth of cloud droplets.

　　At night,the solar energy(stored as vast quantities of heat in city buildings and roads)is slowly released into the city air.Additional city heat is given off at night(and during the day)by vehicles and factories,as well as by industrial and domestic heating and cooling units.The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside.The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas.Overall,the heat island is strongest(1)at night when compensating sunlight is absent;(2)during the winter,when nights are longer and there is more heat generated in the city;and(3)when the region is dominated by a high-pressure area with light winds,clear skies,and less humid air.Over time,increasing urban heat islands affect climatological temperature records,producing artificial warming in climatic records taken in cities.This warming,therefore,must be accounted for in interpreting climate change over the past century.

　　The constant outpouring of pollutants into the environment may influence the climate of the city.Certain particles reflect solar radiation,thereby reducing the sunlight that reaches the surface.Some particles serve as nuclei upon which water and ice form.Water vapor condenses onto these

　　particles when the relative humidity is as low as 70 percent,forming haze that greatly reduces visibility.Moreover,the added nuclei increase the frequency of city fog.

　　Studies suggest that precipitation may be greater in cities than in the surrounding countryside;this phenomenon may be due in part to the increased roughness of city terrain,brought on by large structures that cause surface air to slow and gradually converge.This piling up of air over the city then slowly rises,much like toothpaste does when its tube is squeezed.At the same time,city heat warms the surface air,making it more unstable,which enhances risings air motions,which,in turn,aids in forming clouds and thunderstorms.This process helps explain why both tend to be more frequent over cities.

　　On clear still nights when the heat island is pronounced,a small thermal low-pressure area forms over the city.Sometimes a light breeze—called a country breeze—blows from the countryside into the city.If there are major industrial areas along the outskirts,pollutants are carried into the heat of town,where they tend to concentrate.Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.Pollutants from urban areas may even affect the weather downwind from them.

　　Paragraph 2

　　The urban heat island is due to industrial and urban development.In rural areas,a large part of the incoming solar energy is used in evaporating water from vegetation and soil.In cities,where less vegetation and exposed soil exist,the majority of the Sun’s energy is absorbed by urban structures and asphalt.Hence,during warm daylight hours,less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.The cause of the urban heat island is quite involved.Depending on the location,time of year,and time of day,any or all of the following differences between cities and their surroundings can be important:albedo(reflectivity of the surface),surface roughness,emissions of heat,emissions of moisture,and emissions of particles that affect net radiation and the growth of cloud droplets.

　　1.The word“involved”in the passage is closest in meaning to

　　A.uncertain

　　B.complicated

　　C.common

　　D.clear

　　2.Paragraph 2 mentions all of the following as varying the importance of albedo and other factors EXCEPT

　　A.seasons

　　B.soil depth

　　C.geographic location

　　D.the time of day

　　Paragraph 3

　　At night,the solar energy(stored as vast quantities of heat in city buildings and roads)is slowly released into the city air.Additional city heat is given off at night(and during the day)by vehicles and factories,as well as by industrial and domestic heating and cooling units.The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside.The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas.Overall,the heat island is strongest(1)at night when compensating sunlight is absent;(2)during the winter,when nights are longer and there is more heat generated in the city;and(3)when the region is dominated by a high-pressure area with light winds,clear skies,and less humid air.Over time,increasing urban heat islands affect climatological temperature records,producing artificial warming in climatic records taken in cities.This warming,therefore,must be accounted for in interpreting climate change over the past century.

　　3.The word“retarded”in the passage is closest in meaning to

　　A.disguised

　　B.added to

　　C.made possible

　　D.slowed down

　　Paragraph 4

　　The constant outpouring of pollutants into the environment may influence the climate of the city.Certain particles reflect solar radiation,thereby reducing the sunlight that reaches the surface.Some particles serve as nuclei upon which water and ice form.Water vapor condenses onto these particles when the relative humidity is as low as 70 percent,forming haze that greatly reduces visibility.Moreover,the added nuclei increase the frequency of city fog.

　　4.According to paragraph 4,how do pollutants reduce the distance it is possible to see?

　　A.They increase the amount of sunlight that reaches the ground.

　　B.They increase the relative humidity.

　　C.They form particles that irritate the eye.

　　D.They serve as nuclei around which water condenses.

　　Paragraph 2 and Paragraph 3

　　The urban heat island is due to industrial and urban development.In rural areas,a large part of the incoming solar energy is used in evaporating water from vegetation and soil.In cities,where less vegetation and exposed soil exist,the majority of the Sun’s energy is absorbed by urban structures and asphalt.Hence,during warm daylight hours,less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.The cause of the urban heat island is quite involved.Depending on the location,time of year,and time of day,any or all of the following differences between cities and their surroundings can be important:albedo(reflectivity of the surface),surface roughness,emissions of heat,emissions of moisture,and emissions of particles that affect net radiation and the growth of cloud droplets.

　　At night,the solar energy(stored as vast quantities of heat in city buildings and roads)is slowly released into the city air.Additional city heat is given off at night(and during the day)by vehicles and factories,as well as by industrial and domestic heating and cooling units.The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside.The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas.Overall,the heat island is strongest(1)at night when compensating sunlight is absent;(2)during the winter,when nights are longer and there is more heat generated in the city;and(3)

　　when the region is dominated by a high-pressure area with light winds,clear skies,and less humid air.Over time,increasing urban heat islands affect climatological temperature records,producing artificial warming in climatic records taken in cities.This warming,therefore,must be accounted for in interpreting climate change over the past century.

　　5.Select the TWO answer choices that describe ways mentioned in paragraphs 2 and 3 in which solar energy affects urban and rural areas.To receive credit,you must select TWO answers.

　　A.Solar energy causes evaporation from vegetation and soil,producing a cooling effect.

　　B.Solar energy stored as heat is lost quickly when tall city buildings guide hot air up and away from the surface.

　　C.Solar energy increases the atmospheric pressure over open areas.

　　D.Solar energy is stored up in buildings and roads and emitted as heat during the night.

　　6.Paragraph 3 supports which of the following claims about the interpretation of temperature records?

　　A.The climate may not be warming as much as the increase of temperatures recorded in cities appears to suggest.

　　B.Records show that the increase in urban heat islands has had a significant warming effect on the global climate.

　　C.During most of the past century,temperature records have been misinterpreted.

　　D.Scientists will not be able to account for climate change over the past century until they learn more about the urban heat island.

　　7.All of the following are mentioned in paragraph 3 as contributing to an increase in the amount of heat within a city EXCEPT

　　A.home air conditioners

　　B.cars and trucks

　　C.streetlights

　　D.factory buildings

　　8.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?Incorrect choices change the meaning in important ways or leave out essential information.(文中未显示阴影部分)

　　A.Until more studies are done,suggestions about the causes of precipitation in cities will focus on the roughness of terrain rather than on surface air and convergence.

　　B.Certain phenomena of city landscapes,such as large structures,cause surface air to slow and converge,which brings a change in weather patterns to cities and rural areas.

　　C.One reason why precipitation may be greater in cities than in the countryside is that large buildings that are found in cities cause surface air to slow and converge.

　　D.Studies that focus on large structures,which are only partly responsible for the increased roughness of city terrain,are incomplete in their explanation of increased precipitation.

　　Paragraph 5

　　Studies suggest that precipitation may be greater in cities than in the surrounding countryside;this phenomenon may be due in part to the increased roughness of city terrain,brought on by large structures that cause surface air to slow and gradually converge.This piling up of air over the city then slowly rises,much like toothpaste does when its tube is squeezed.At the same time,city heat warms the surface air,making it more unstable,which enhances risings air motions,which,in turn,aids in forming clouds and thunderstorms.This process helps explain why both tend to be more frequent over cities.

　　9.Why does the author mention“toothpaste”being squeezed from a tube?

　　A.To compare the movement of toothpaste from a tube to the movement of precipitation from clouds

　　B.To suggest that the process of cloud formation is a simple,everyday experience

　　C.To help the reader visualize the process of air movement over a city

　　D.To contrast the slow rising of air currents with the rapid squeezing of toothpaste

　　10.The word“both”in the passage refers to

　　A.piling up and warming of air

　　B.clouds and thunderstorms

　　C.warm surface air and rising air motions

　　D.heat and instability

　　Paragraph 6

　　On clear still nights when the heat island is pronounced,a small thermal low-pressure area forms over the city.Sometimes a light breeze—called a country breeze—blows from the countryside into the city.If there are major industrial areas along the outskirts,pollutants are carried into the heat of town,where they tend to concentrate.Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.Pollutants from urban areas may even affect the weather downwind from them.

　　11.The word“pronounced”in the passage is closest in meaning to

　　A.examined

　　B.relative

　　C.strongest

　　D.darkest

　　12.According to paragraph 6,the highest concentration of pollutants is likely to be found

　　A.in the center of the city

　　B.over industrial areas outside the city

　　C.in rural areas downwind of the city

　　D.high in the atmosphere during daylight hours

　　12.Look at the four squares[■]that indicate where the following sentence could be added to the passage.

　　The resulting difference in atmosphere pressure between the city and the countryside can cause air to shift.

　　Where would the sentence best fit?Click on a square[■]to add the sentence to the passage.

　　On clear still nights when the heat island is pronounced,a small thermal low-pressure area forms over the city.■Sometimes a light breeze—called a country breeze—blows from the countryside into the city.■If there are major industrial areas along the outskirts,pollutants are carried into the heat of town,where they tend to concentrate.■Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.■Pollutants from urban areas may even affect the weather downwind from them.

　　13.Directions:An introductory sentence for a brief summary of the passage is provided below.Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage.Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage.This question is worth 2 points.

　　Drag your answer choices to the spaces where they belong.To remove an answer choice,click on it.

　　To review the passage,click VIEW TEXT.

　　Cities are generally warmer than the surrounding countryside,a phenomenon known as the urban heat island.

　　Answer Choices

　　A.In the countryside,much solar energy is used in evaporation,but in the city this energy builds up as heat.

　　B.Increased industrial and urban development has also increased average levels of humidity over the last century.

　　C.Pollution from cars and factories helps increase the amounts of fog and precipitation that occur in cities.

　　D.The urban heat island is strongest in the summer,when the days are long and the sunlight is intense.

　　E.Heat and air are trapped in the irregular spaces between buildings,which creates the atmospheric conditions that result in storms and winds.

　　F.Country breezes blow pollutants put from the cities into the surrounding countryside.

　　Q1

　　正确答案：B

　　解析：involved：“卷入的;有关的;复杂的”;原文说城市热岛的成因非常involved，后文说由于位置、一年里的时间、一天里的时间等等多项因素，结合选项，只能选择B选项complicated“复杂的”;其余三个选项常见意分别为“不确定的”，“常见的”和“清楚的”。

　　Q2

　　正确答案：B

　　解析：根据题干定位原文段落的最后一句，time of year对应A选项的seasons;C选项对应句中的location;D选项原文重现。

　　Q3

　　正确答案：D

　　解析：retarded：智力迟钝的;发展迟缓的。在文中就是取第二个意思，表示缓慢的，对应D选项，从后文来看，下一句中的The slow release of heat的slow已经有所指代。

　　Q4

　　正确答案：D

　　解析：根据题干定位原文“Certain particles…visibility.”粒子反射太阳辐射，减少到达地面的阳光(第2句，与A选项矛盾);有些粒子是水和冰凝结成的核，当相对湿度低到70%，水蒸气也浓缩凝结在这些粒子上，形成雾霾。结合选项，B选项曲解了原文意思，只是提到了相对湿度，没有说它们增加湿度;C选项没有提及;只能选择D选项。

　　Q5

　　正确答案：A D

　　解析：根据题干对solar energy进行定位，P2开头第二句提到“In rural areas，a large part…vegetation and soil.”对应A选项;P3开头前两句“At night，…cooling units.”对应D选项;两个地方的定位句和两个选项都是同义表达，因此答案是A和D。

　　Q6

　　正确答案：A

　　解析：根据题干的interpretation of temperature定位原文信息到本段的最后两句，最后两句说：城市热岛效应影响了气象学上的温度记录，导致了artificial warming(人为热岛效应的变暖)被记录在城市气候记录上;因此，理解过去一个世纪以来的气候变化必须要考虑这种变暖带来的影响。作者其实也就是在说：所谓记录的温度增加和气候变化一定要考虑这种人造的城市热岛效应，实际上看city climate records的时候，这种温度升高可能是虚高的，或者根本没有那么高，是城市热岛效应导致的呢。正好对应A选项。

　　Q7

　　正确答案：C

　　解析：答案在本段第2句。A选项对应本句提到的“domestic heating and cooling units”;B选项和D选项对应本句提到的“vehicles and factories”。

　　Q8

　　正确答案：C

　　解析：精简一下高亮句的文本：1.Precipitation may be greater in cities;2.It is partly due to the increased roughness of city terrain;3.The increased roughness of city terrain is brought by the large structures,they cause surface air to slow and gradually converge.中文简化就是：城市的大型建筑导致地表空气流动变慢，逐渐汇集，这种现象又增加了城市地形高低不平，进而可能导致城市里的降水量比农村地区多。对应选项，只有C选项符合。

　　Q9

　　正确答案：C

　　解析：这是一道修辞题。toothpaste是作者的一个形象的比喻，说的是城市上方的空气汇集后然后缓慢上升，很像是从牙膏管里挤出牙膏一样。作者把piling-up air上升的过程比作了挤牙膏的过程。

　　Q10

　　正确答案：B

　　解析：问的是both指代的是什么。先要知道both所在句子的This process是什么。前一句说到：同时，城市热量让城市表面的空气变暖，让它变得更不稳定，这样就增强了空气上升的运动过程，这个运动过程反过来帮助形成云和雷雨。这个运动过程就是This process，both所在句还说这个过程让both在城市里更频繁地发生。这样梳理过后，发现both就是指代最近的clouds and thunderstorms。

　　Q11

　　正确答案：C

　　解析：pronounced：strongly marked;easily noticeable，显著的;C选项为同义表达。

　　Q12

　　正确答案：A

　　解析：问的是污染物浓度最高的地方有可能是在哪里。低气压区域在城市上空形成后，有时候乡村风从乡村吹到城市。如果沿着郊区有重工业区，污染物就顺着风被带到城市中心，他们最容易在那里集中。最容易concentrate的地方就是市中心。所以对应选项A。

　　Q13

　　正确答案：插入第一个方框中(A)

　　解析：插入文本的意思是：农村和城市在大气压上的差异引起空气移动。所以插入文本的后面肯定会讲述空气是怎么移动的。对应四个方框，应该选择A选项。

　　Q14

　　正确答案：A C E

　　解析：A选项对应文章第二段，比较了城市和农村太阳能的吸收和利用情况，参见Q5;C选项前半句内容对应文章第三段，参见Q7，precipitation的信息对应文章第五段开头部分，城市里的确降雨会多一些;E选项对应第五段和第六段内容，参见Q10。