| 单词 | stratosphere | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| 释义 | stratospherestrat·o·sphereS0797900 (străt′ə-sfîr′)stratosphere(ˈstrætəˌsfɪə)strat•o•sphere(ˈstræt əˌsfɪər)n. strat·o·sphere(străt′ə-sfîr′)stratospherestratosphere
stratospherestratosphere(străt`əsfēr), second lowest layer of the earth's atmosphereatmosphere[Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other planets and satellites are known, only the earth's atmosphere has been well studied, the science of ..... Click the link for more information. . The level from which it extends outward varies with latitude; it begins c.5 1-2 mi (9 km) above the poles, c.6 or 7 mi (c.10 or 11 km) in the middle latitudes, and c.10 mi (16 km) at the equator, and extends outward c.20 mi (32 km). It is a zone of dry, thin air, cold and clear, with a horizontal temperature gradient, that, in its lower level, is the reverse of that near the earth's surface. In polar regions the temperature is −40°F; to −50°F; (−40°C; to −46°C;), but near the equator it ranges from −80°F; to below −100°F; (−62°C; to below −74°C;); in the middle latitudes it remains steady at about −67°F; (−55°C;). The stratified variations in temperature were deduced from the behavior of sound waves transmitted through the atmosphere, which travel faster in warm air than in cold air. Weather balloonsweather balloon, Within the stratosphere at altitudes of 12 to 30 mi (19–48 km) is the ozone layerozone layer Measurements of Antarctica's ozone layer have registered a consistent seasonal "hole," or thinning, in the layer above the South Pole since 1985, and since then similar thinnings have been found over other areas of the world. There is evidence that the ozone is being broken down by chlorine atoms that are released when sunlight breaks up substances such as chlorofluorocarbonschlorofluorocarbons Stratospherethe layer of the atmosphere between the troposphere and the mésosphère. It extends from a height of 8–16 km to a height of 45–55 km. The temperature in the stratosphere on the whole increases with height. The gas composition of the air in the stratosphere is similar to that in the troposphere, but the stratosphere has less water vapor and more ozone (O3). The highest concentration of O3 is in the layer from 20 to 30 km. Thermal conditions in the stratosphere are basically determined by radiative heat exchange and, to a lesser degree, by the vertical and horizontal motions of the air. As a whole, the stratosphere is close to a state of radiative equilibrium—that is, the temperature in the stratosphere is determined by the energy absorbed by the H2O, CO2, and O3 molecules being equal to the energy emitted by the molecules. The stratospheric air is heated mainly through the absorption of ultraviolet solar radiation by the ozone. On the other hand, the long-wavelength radiation of the H2O and CO2 molecules leads to cooling of the air. As a result, at low latitudes, where the quantity of H2O and CO2 is increased and there is less O3, the stratosphere is colder than over high latitudes. In mid-latitudes and high latitudes, the temperature changes little with height in the lower half of the stratosphere but increases in the upper half. Over the equator and the tropics, the temperature increases with height throughout the stratosphere. At the lower boundary of the stratosphere, the temperature varies from – 40°C (– 60°C) over the polar regions and mid-latitudes to –70°C (– 80°C) over the tropics. At the upper boundary of the stratosphere, the temperature is on the average close to 0°C. High wind speeds and jet streams are observed in the stratosphere. In the summer, above 20–25 km, the prevailing wind direction changes from west to east. In the winter, westerly winds are found throughout the stratosphere. The greatest wind speeds are observed at the upper boundary of the stratosphere, where speeds may reach 80–100 m/sec in the winter and 60–80 m/sec in the summer. At heights of 20–30 km, nacreous clouds are sometimes found; they apparently consist of ice crystals or supercooled droplets of water. The lower stratosphere at about 20–25 km has an increased content of aerosol particles, particularly sulfate particles from volcanic eruptions. Because of the low turbulent exchange and the absence of the washing out by precipitation, the aerosol particles have a longer lifetime here than they do in the troposphere. By increasing the atmospheric albedo, this aerosol layer of the stratosphere leads to a drop in air temperature at the earth’s surface; the decrease is particularly marked after large explosive eruptions of volcanoes. REFERENCESKhvostikov, I. A. Vysokie sloi atmosfery. Leningrad, 1964. Chapter 5, subsec. 14; ch. 9, subsec. 27.Logvinov, K. T. Meterologicheskie parametry stratosfery. Leningrad, 1970.
stratosphere[′strad·ə‚sfir]stratosphere stratospherestratospherestratospherethe region of the Earth's atmosphere between 10 and 50km in altitude.See STRATO stratosphere
Words related to stratosphere
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
| 随便看 |
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
英语词典包含2567994条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。