专业英语6-new

1、Unit SixSevere Storms第六课：强风暴New Words glossary n. 词汇 blizzard n. 雪暴 snowfall n. 降雪 snowdrift n. 雪堆 coat v. 覆盖 hailstorm n. 雹暴 wake n. 尾流 rate v. 评价；rate n. 比率，速度 , e.g., at a rate of，以的速率 devastating a. 破坏性的； devastate v. ; devastation n. top v. 封顶，盖住； top n. 顶 radiosonde n. 无线电探空仪 enlarge v. 放大 en+

2、 n./adj./- v. enrich, endanger, enable, downdraft n. 下曳气流； updraft n. 上升气流 upper-level n. 高层，高空； lower-level n. 低层，低空 mid-level 中层 outflow v. 流出； inflow v. 流出 blast n. 阵风； gust n.阵风;一阵狂风 airline n. 航线，航空公司；flight n. 航班 typhoon n. 台风； hurricane n. 飓风； tropical cyclone n. 热带气旋； tropical storm n. 热带风暴

3、cyclone n. 气旋；cyclonic a. 气旋性的; vortex n. 涡旋 anticyclone n. 反气旋； anticyclonic a. 反气旋性的 destructive a. 破坏性的 multi-cell n. 多单体； super-cell n. 超级单体 water-rich a. 含水丰富的 waterspout n. 水龙卷 ; tornado n. 龙卷；whirl n.旋风，涡旋 suction n. 虹吸，吸（水） exterior n. 外部； interior n. 内部 exploration n. 探索 hook-shaped a. 钩状的T

4、extParagraph 1 According to the Glossary of Meteorology, a storm is “any disturbed state of the atmosphere, especially as affecting the earths surface and strongly implying destructive or otherwise unpleasant weather”. In winter most storms are cyclonic in nature; they cover large areas, produce rai

5、n or snow, and often are cold and windy. These storms usually do more good than harm because the precipitation they yield waters farms and fills streams, lakes, and reservoirs.Paragraph 2 Sometimes winter cyclones become intense as their central pressures fall. As a result the winds increase in stre

6、ngth, and if there is adequate atmospheric moisture, there can be flood-causing rains or heavy snow falls that close down entire cities. In some cases blizzards occur as strong, cold winds that carry the snow into large snow-drifts. In such storms, grazing animals on the open range can become isolat

7、ed, run out of food or even freeze to death.Paragraph 3 Among the most dangerous of winter storms are those that produce freezing rain. By coating streets, highways, and airports runways with ice, the storms cause a large number of motor vehicle accidents and pose serious hazards at airports.Paragra

8、ph 4 Winter storms usually develop gradually, move slowly, and can be predicted with a reasonable degree of accuracy. On the other hand, severe storms of a convective nature develop so rapidly and are so small and short-lived that they are difficult to forecast. Violent thunderstorms, hailstorms, an

9、d tornadoes develop in tens of minutes and can strike with frighten suddenness. In minutes a hailstorm can destroy a field of wheat or a tornado can demolish a score of buildings, leaving injured and dead in its wake.Paragraph 5-1 Another type of severe storms, the hurricanes and its counterparts in

10、 other parts of the words, are relatively large, intense tropical cyclones. Although they do not contain the concentrated power of tornadoes, hurricanes are more energetic, larger and longer-lived, and therefore they can do more damage than tornadoes. Occasionally, individual violent storms can caus

11、e great losses. In some parts of the world extreme weather can take human tolls that nearly defy belief. For example, a tropical cyclone that struck Bangladesh in November in 1970 took more than a quarter of million lives and rates as one of natures most devastating calamities. The storm was a South

12、east Asian version of the South Atlantic hurricane.Paragraph 5-2 Paragraph 6 Commonly, thunderstorms extend to altitudes of about 10 km and often are topped by anvil clouds composed of the crystals blowing away from the main cloud regions. Although thunderstorms take on many sizes, shapes, and struc

13、tures, they may be considered to fall into two broad categories: local or air mass thunderstorms and organized thunderstorms. Paragraph 7 Local storms are fairly isolated and have a short lifetimeless than an hour or so. A great deal was learned by flying instrumented airplanes through thunderstorms

14、 and by observing them by means of radar, radiosonde, and other ground-based instruments. A local thunderstorm is made up of one or more “cells” each of which follows a three-stage life cycle: cumulus stage, mature stage and dissipating stage. Paragraph 8Paragraph 10-1 Under the cloud, even before r

15、ain reaches the ground, there often is a downward rush of cool air that spreads rapidly outward away from the cloud. Depending on the strength of the upper-level winds and of the downdraft, outflowing surface winds can range from light breezes to strong blasts. The cool air usually advances ahead of

16、 the thunderstorm, and sometimes does appreciable damage to vegetation and buildings. The downdrafts and outflowing air and the associated wind shear represent a serious hazard to airplanes in the process of landing and taking off. Particularly strong downdrafts have been termed “downbursts” which a

17、re responsible for a number of crashes by commercial airlines.Paragraph 10-2Hurricanes飓风Paragraph 11 Tropical cyclones that occur over the Atlantic Ocean and the Gulf of Mexico and have maximum wind speeds greater than 32.6 m/s (73 mi/hr) are called hurricanes. Similar storms over the western North

18、Pacific are called typhoons. The ones that develop over the Indian Ocean and affect India and southeast Asia are called cyclones. Hurricanes of the Pacific coast of Mexico have been named cyclones by the natives of the country. Various other names are used in other parts of the world.Paragraph 12-1

19、The paths followed by hurricanes are determined mostly by the prevailing wind currents in which the hurricanes are located. In their developing stages the storms are transported by easterly winds that prevail over the tropics. As the “steering” current changes, the hurricane path also changes. In so

20、me cases there are abrupt shifts in the direction of travel. As hurricanes move over land or over higher-latitude oceans, they become weaker. This occurs primarily because the energy input is reduced as the storm leaves the regions of warm ocean water. In addition, when a hurricane passes over a con

21、tinent, the terrain exerts additional frictional force that act to reduce the speeds.Paragraph 12-2 Hurricanes passing over land can be very destructive and lethal. When hurricane Camille swept into Mississippi in August 1969, it caused about 1.5 billion of damage. The torrential rains from hurrican

22、e Agnes in 1972 caused massive flooding over the eastern United States. Although it was not true in the case of Agnes, loss of life and destruction of property usually are a result of the storm surge, a wave of ocean water generated by the hurricanes winds as the storm approaches the coast. Paragrap

23、h 13-1 A wall of water some 3m or more in height can be produced. As it swept over low-lying land, it can cause devastating floods.Paragraph 13-2Hailstones冰雹Paragraph 14 Hail usually is produced by large, long-lasting thunderstorm classified as multicell or supercell thunderstorms. The thunderstorm

24、often are arranged in lines or bands that are call squall lines and occur most often in the spring and early summer months. These are the periods when atmospheric conditions are most favorable for the development of violent thunderstorms. According to a highly regarded hailstorm model, first offered

25、 by two English scientists, hailstones began to form in the water-rich, rising air that enters the cloud along its leading edge. As they grow by colliding with supercooled drops, the hailstones fall at increasing speeds through the air and intercept increasing quantities of supercooled water. If the

26、 updraft speed exceeds the terminal velocity of the hailstones, they are carried upward.Paragraph 15-1Paragraph 15-2 The upper-level winds move them forward across the upper part of the storm to a region of weaker updrafts. If the updrafts are not strong enough to hold up the hailstones, they fall t

27、oward the ground. After descending several kilometers, some of the stones fall into the strong updraft core and are carried upward again for a second passage through the supercooled cloud. A series of such trips can lead to large hailstones. As ice particle starting with a diameter of 1 mm can grow

28、to 3 cm after exposure to the high liquid water contents in a strong updraft. In thunderstorms with strong, persistent updrafts, large hailstones can be grown without the recycling process.Paragraph 15-3Tornadoes龙卷 Thunderstorms producing large hail are also likely to produce tornadoes. Contrary to

29、the opinions of many people, tornadoes are not particularly energetic. An average tornado contains much less energy than the thunderstorm that produces it, and is appreciably less energetic cyclone. But since the energy of a tornado is expended in a short period of time, its power-energy divided by

30、time is relatively high. Because of their concentrated power, tornadoes are probably the most feared of all weather phenomena. Paragraph 16-1 They often strike suddenly, with little warning, and in a few minutes cause extensive damage to property, injuries, and loss of life. A tornado may have the a

31、ppearance of a narrow funnel, cylinder, or rope extending from the base of a thunderstorm to the ground. The visible funnel consists mostly of water droplets formed by condensation in the funnel. Near the ground blowing dust, leaves, and other debris identify the presence of a strong vortex. Tornado

32、es and weak visible vortex observed over watermost often in the tropics and subtropicsare called waterspouts.Paragraph 16-2 Tornadoes are generally small, typically less than a few hundred meters in diameter, but some are larger than 1 km. With rare exceptions the winds are cyclonic, that is , they

33、blow counterclockwise in the Northern Hemisphere. The funnels usually touch the ground for only a few minutes or so, but some have been reported to last for much more than an hour. The maximum wind speeds in tornadoes usually are between about 33 and 100 m/s (73 and 224 mi/hr), but occasionally they

34、 may exceed 120 m/s. Paragraph 17-1 the higher the intensity rating, the greater is the damage potential of a tornado. Most of the fatalities and property destruction are caused by a small number of large, long-lived tornadoes. During the decade ending in 1970 fewer that 2 percent of the largest tor

35、nadoes accounted for 85 percent of the fatalities. Paragraph 17-2 Within a tornado there are still smaller, intense whirls that Fujita calls suction vortices. They have diameters of about 10 m. A small, short-lived tornado might have only one; a maxi-tornado would have many suction vortices. Fujita

36、proposed that these small vortices account for occasional observations of virtually total destruction of one structure while another one 10 m away is left unscathed.Paragraph 18Paragraph 19 The pressure in a tornado funnel is substantially lower than the surrounding atmospheric pressure. It has been

37、 estimated that in a very severe tornado the central pressure might be more than 100mb less than the pressure outside the funnel. The pressure differences between the interior and exterior of a tornado can account in part for the damage to buildings whose doors and windows are closed tightly. When a

38、 tornado moves over such a structure, the outside pressure drops rapidly while the pressure inside falls more slowly. The resulting pressure differences augment those caused by the dynamical effects of the wind. Paragraph 20-1 When the pressure inside a building substantially exceeds the pressure on

39、 the outside, the result is a strong outward pressure force. Such a force can do extensive damage; in some cases it could pick up the roof and blow out the wall of a building.Paragraph 20-2Paragraph 21 Tornadoes as is the case with hail are most frequent in the late afternoon and early evening and occur in the spring and early summer months. It is during th