The city is an extraordinary processor of mass and energy and has its own metabolism. A daily input of water, food, and energy of various kinds is matched by an output of sewage, solid waste, air pollutants, energy, and materials that have been transformed in some way. The quantities involved are enormous. Many aspects of this energy use affect the atmosphere of a city, particularly in the production of heat.
In winter the heat produced by a city can equal or surpass the amount of heat available from the Sun. All the heat that warms a building eventually transfers to the surrounding air, a process that is quickest where houses are poorly insulated. But an automobile produces enough heat to warm an average house in winter, and if a house were perfectly insulated, one adult could also produce more than enough heat to warm it. Therefore, even without any industrial production of heat, an urban area tends to be warmer than the countryside that surrounds it.
The burning of fuel, such as by cars, is not the only source of this increased heat. Two other factors contribute to the higher overall temperature in cities. The first is the heat capacity of the materials that constitute the city, which is typically dominated by concrete and asphalt. During the day, heat from the Sun can be conducted into these materials and stored—to be released at night. But in the countryside materials have a significantly lower heat capacity because a vegetative blanket prevents heat from easily flowing into and out of the ground. The second factor is that radiant heat coming into the city from the Sun is trapped in two ways: (1) by a continuing series of reflection among the numerous vertical surfaces that buildings present and (2) by the dust dome, the cloudlike layer of polluted air that most cities produce. Shortwave radiation from the Sun passes through the pollution dome more easily than outgoing longwave radiation does; the latter is absorbed by the gaseous pollutants of the dome and reradiated back to the urban surface.
Cities, then, are warmer than the surrounding rural areas, and together they produce a phenomenon known as the urban heat island. Heat islands develop best under particular conditions associated with light winds, but they can form almost any time. The precise configuration of a heat island depends on several factors. For example, the wind can make a heat island stretch in the direction it blows. When a heat island is well developed, variations can be extreme; in winter, busy streets in cities can be 1.7℃ warmer than the side streets. Areas near traffic lights can be similarly warmer than the areas between them because of the effect of cars standing in traffic instead of moving. The maximum differences in temperature between neighboring urban and rural environments is called the heat-island intensity for that region. In general, the larger the city, the greater its heat-island intensity. The actual level of intensity depends on such factors as the physical layout, population density, and productive activities of a metropolis.
The surface-atmosphere relationships inside metropolitan areas produce a number of climatic peculiarities. For one thing, the presence or absence of moisture is affected by the special qualities of the urban surface. With much of the built-up landscape impenetrable by water, even gentle rain runs off almost immediately from rooftops, streets, and parking lots. Thus, city surfaces, as well as the air above them, tend to be drier between episodes of rain; with little water available for the cooling process of evaporation, relative humidities are usually lower. Wind movements are also modified in cities because buildings increase the friction on air flowing around them. This friction tends to slow the speed of winds, making them far less efficient at dispersing pollutants. On the other hand, air turbulence increases because of the effect of skyscrapers on airflow. Rainfall is also increased in cities. The cause appears to be in part greater turbulence in the urban atmosphere as hot air rises from the built-up surface.
Paragraph 1: The city is an extraordinary processor of mass and energy and has its own metabolism. A daily input of water, food, and energy of various kinds is matched by an output of sewage, solid waste, air pollutants, energy, and materials that have been transformed in some way. The quantities involved are enormous. Many aspects of this energy use affect the atmosphere of a city, particularly in the production of heat.
1. The word “enormous” in the passage is closest in meaning to
○ growing
○ frightening
○ very large
○ strictly controlled
Paragraph 2: In winter the heat produced by a city can equal or surpass the amount of heat available from the Sun. All the heat that warms a building eventually transfers to the surrounding air, a process that is quickest where houses are poorly insulated. But an automobile produces enough heat to warm an average house in winter, and if a house were perfectly insulated, one adult could also produce more than enough heat to warm it. Therefore, even without any industrial production of heat, an urban area tends to be warmer than the countryside that surrounds it.
2. The word “surpass” in the passage is closest in meaning to
○ remain below
○ be higher than
○ add to
○ come close to
3. According to paragraph 2, how soon heat from a warmed house reaches the outside air greatly affected by
○ how well the house is heated
○ how well the house is insulated
○ how many adults live in the house
○ how much sunshine the house receives
Paragraph 3: The burning of fuel, such as by cars, is not the only source of this increased heat. Two other factors contribute to the higher overall temperature in cities. The first is the heat capacity of the materials that constitute the city, which is typically dominated by concrete and asphalt. During the day, heat from the Sun can be conducted into these materials and stored—to be released at night. But in the countryside materials have a significantly lower heat capacity because a vegetative blanket prevents heat from easily flowing into and out of the ground. The second factor is that radiant heat coming into the city from the Sun is trapped in two ways: (1) by a continuing series of reflection among the numerous vertical surfaces that buildings present and (2) by the dust dome, the cloudlike layer of polluted air that most cities produce. Shortwave radiation from the Sun passes through the pollution dome more easily than outgoing longwave radiation does; the latter is absorbed by the gaseous pollutants of the dome and reradiated back to the urban surface.
4. According to paragraph 3, each of the following contributes to making urban areas warmer than the surrounding countryside EXCEPT
○ the fuel burned by motor vehicles
○ the capacity to store heat of the materials used in building a city
○ the easy flow of heat into the ground in city areas covered by vegetation
○ the repeated reflection of solar radiation back and forth among buildings
5. According to paragraph 3, why do materials in the countryside have a lower heat capacity than materials in cities do?
○ The countryside in the Sun is the only important source of heat.
○ Construction materials in the city are not as good at keeping buildings warm as they are in the countryside.
○ In the countryside the solar heat that flows into the ground flows out again quickly.
○ Countryside vegetation prevents heat from being trapped in the ground.
6. How is paragraph 3 organized?
○ It describes two factors that contribute to the increased heat of cities and then provides two causes for the second factor.
○ It describes two causes discovered in an early analysis of the increased heat of cities.
○ It describes two factors that contribute to the increased heat of cities and two other factors that work against it.
○ It describes two well-established causes of the increased heat of cities and other two whose roles are less well understood.
Paragraph 4: Cities, then, are warmer than the surrounding rural areas, and together they produce a phenomenon known as the urban heat island. Heat islands develop best under particular conditions associated with light winds, but they can form almost any time. The precise configuration of a heat island depends on several factors. For example, the wind can make a heat island stretch in the direction it blows. When a heat island is well developed, variations can be extreme; in winter, busy streets in cities can be 1.7℃ warmer than the side streets. Areas near traffic lights can be similarly warmer than the areas between them because of the effect of cars standing in traffic instead of moving. The maximum differences in temperature between neighboring urban and rural environments is called the heat-island intensity for that region. In general, the larger the city, the greater its heat-island intensity. The actual level of intensity depends on such factors as the physical layout, population density, and productive activities of a metropolis.
7.The word “configuration” in the passage is closest in meaning to
○ location
○ history
○ temperature
○ shape
8. According to paragraph 4, what can explain the substantial differences in temperature between one area and other within a well-developed heat island?
○ The overall size of the heat island that includes the two reasons
○ The intensify of the heat island that includes the two areas
○ Differences between the two areas in the general level of activity, including traffic
○ Differences between the two areas in the insulation materials used in construction
9. Paragraph 4 supports the idea that a city’s heat-island intensity would increase if
○ the city went into an economic decline and lost population
○ the city’s economy shifted from heavy industry to health care and education
○ there was an upward trend in the average age of the city’s residents
○ repair work on the streets slowed traffic throughout the city
Paragraph 5: The surface-atmosphere relationships inside metropolitan areas produce a number of climatic peculiarities. For one thing, the presence or absence of moisture is affected by the special qualities of the urban surface. With much of the built-up landscape impenetrable by water, even gentle rain runs off almost immediately from rooftops, streets, and parking lots. Thus, city surfaces, as well as the air above them, tend to be drier between episodes of rain; with little water available for the cooling process of evaporation, relative humidities are usually lower. Wind movements are also modified in cities because buildings increase the friction on air flowing around them. This friction tends to slow the speed of winds, making them far less efficient at dispersing pollutants. On the other hand, air turbulence increases because of the effect of skyscrapers on airflow. Rainfall is also increased in cities. The cause appears to be in part greater turbulence in the urban atmosphere as hot air rises from the built-up surface.
10. According to paragraph 5, surfaces in the city are generally drier than surfaces in the countryside between periods of rainfall because
○ in the city gentle rain is much more common than heavy rain
○ high temperatures in the city speed up the process of evaporation
○ in the city there are longer periods of dry weather between episodes of rain
○ rainwater in the city cannot soak into most surfaces and quickly runs off
11. The word “modified” in the passage is closest in meaning to
○ changed
○ blocked
○ increased
○ weakened
12. According to paragraph 5, which of the following is a factor responsible for the greater air turbulence in urban environments?
○ The high speed of the winds travelling above cities
○ The greater rainfall totals recorded in cities
○ Attempts to reduce urban air pollution
○ The effects of tall buildings on airflow
Paragraph 4: Cities, then, are warmer than the surrounding rural areas, and together they produce a phenomenon known as the urban heat island. Heat islands develop best under particular conditions associated with light winds, but they can form almost any time. ■The precise configuration of a heat island depends on several factors. ■For example, the wind can make a heat island stretch in the direction it blows. ■When a heat island is well developed, variations can be extreme; in winter, busy streets in cities can be 1.7℃ warmer than the side streets. ■Areas near traffic lights can be similarly warmer than the areas between them because of the effect of cars standing in traffic instead of moving.
The maximum differences in temperature between neighboring urban and rural environments is called the heat-island intensity for that region. In general, the larger the city, the greater its heat-island intensity. The actual level of intensity depends on such factors as the physical layout, population density, and productive activities of a metropolis.
13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.
Another possibility is for the heat island to be stretched along the course of major rivers, since large waterways typically have a warming effect on the air directly above them.
Where would the sentence best fit?
14. 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 answer choices 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.
Cities create climatic conditions of their own through their physical structure and urban activities.
●
●
●
Answer Choices
○ The amount of heat produced in a city will be reduced when cities use the heat from cars to warm homes.
○ The built-up landscape of the city readily becomes a heat island, with greater water runoff and special climatic conditions such as low relative humidity and increased air turbulence.
○ The materials from which cities are built and the effects of pollution domes help make urban areas warmer than rural areas.
○ Cities tend to be warmer than their surrounding areas, in part because they produce heat by burning fuel for heating, powering vehicles, and industrial production.
○ In most cities, the heating that results from solar radiation is intensified by carbon dioxide, a gas that is present at very high concentrations in cities’ atmospheres.
○ During periods without rainfall, the air in cities heats up and causes winds to slow down, with the result that pollutants are not dispersed.
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Cities tend to be warmer…
城市氣候
城市是一個(gè)物質(zhì)和能量的巨大處理器，擁有自己的新陳代謝。每天輸入水、食物和各種各樣的能量，相應(yīng)的輸出廢水、廢氣、固體垃圾、廢能和某種程度上已經(jīng)變形的材料。這個(gè)過程中的物質(zhì)轉(zhuǎn)移量異常的大。這種能源的消耗在很多方面影響城市的氣候，尤其是產(chǎn)生熱量方面。
冬天城市所產(chǎn)生的熱量可以達(dá)到或超過其從太陽那里接收的熱量。所有用來供暖的熱量最后都擴(kuò)散至周圍的空氣中，這個(gè)過程在那些隔熱效果差的房屋里進(jìn)行得最快。一輛汽車所產(chǎn)生的熱量足以為一個(gè)普通的房屋供暖，如果房屋隔熱效果好，一個(gè)成年人產(chǎn)生的熱量就足以讓其保暖了。因此，即使沒有任何工業(yè)產(chǎn)熱，城市地區(qū)也會比它周圍的鄉(xiāng)村地區(qū)更暖和。
燃料的燃燒，比如汽車燃料，并不是這種熱量增加的唯一來源。另外兩個(gè)因素導(dǎo)致了城市較高的整體溫度。第一個(gè)是建造城市的材料的熱容，主要典型材料是瀝青和混凝土。白天，來自太陽的熱量傳入到這些物質(zhì)當(dāng)中并儲存起來，在晚上被釋放。但是在鄉(xiāng)村儲存能量的物質(zhì)熱容更低，因?yàn)橹脖粫柚篃崃枯p易流入和流出地面。第二個(gè)因素是從太陽到城市的輻射熱以兩種形式被攔截了：（1）通過大量建筑的垂直表面的不斷反射（2）通過塵埃，即大多數(shù)城市中受污染空氣組成的云狀物質(zhì)。來自太陽的短波輻射比長波輻射要更容易穿過污染層；后者被這層物質(zhì)中的氣體污染物所吸收，然后重新輻射到城市的表層。
城市要比它周圍的鄉(xiāng)村地區(qū)熱，同時(shí)它們產(chǎn)生了被稱為城市熱島的現(xiàn)象。熱島效應(yīng)在特殊條件下尤其是有微風(fēng)時(shí)最明顯，但是卻幾乎在任何時(shí)候都能形成。熱島的準(zhǔn)確狀態(tài)決定于好幾個(gè)因素。比如風(fēng)能在它出現(xiàn)的地方形成一個(gè)區(qū)域性的熱島。當(dāng)一個(gè)熱島完全形成時(shí)，溫度變化可能會非常極端；在冬天，繁忙的街道可能要比旁邊的街道溫度高1.7℃。那些紅綠燈附近的地區(qū)同樣要比紅綠燈之間的地區(qū)要暖和，因?yàn)槠囃Ｖ箷r(shí)候的熱效應(yīng)要比運(yùn)動時(shí)明顯。城市周邊和鄉(xiāng)村環(huán)境的最大不同是地區(qū)熱島效應(yīng)的程度。一般來講，城市越大，熱島效應(yīng)的程度就越強(qiáng)。實(shí)際上熱島效應(yīng)的程度取決于實(shí)際布局、人口密度、和城市的生產(chǎn)活動等諸多因素。
在大都市里表面大氣之間的關(guān)系產(chǎn)生了一系列特殊的氣候特征。首先，濕氣的存在與否受到了城市表層特殊性質(zhì)的影響。由于水無法穿過大多數(shù)城市建筑，即使是很小的雨也會立即從屋頂、街道和停車場流到地下。這樣城市表層包括其空氣在雨季的間歇期就會比較干燥；由于蒸發(fā)的冷卻過程缺少水分，相對濕度通常也很低。氣流會因?yàn)槌鞘薪ㄖ哪Σ炼淖�。這種摩擦?xí)档惋L(fēng)速，使得氣體擴(kuò)散污染物的效率降低。另一方面，湍流也會因?yàn)槟μ齑髽堑挠绊懚黾印３鞘薪涤暌苍黾恿�。其原因部分在于從地表上升的熱空氣所造成的城市大氣中的更大湍流�?/span>
