气象科技英语翻译

Like a fish in the ocean, man is confined to a very shallow layer of atmosphere.The gaseous envelope of the Earth is physically inhomogeneous in both the vertical and horizontal directions, although the horizontal inhomogeneity is much less marked than the vertical inhomogeneity.Various criteria have been devised for dividing the atmosphere into layers. This division can be based on the nature of the vertical temperature profile, on the gaseous composition of the air at different altitudes, and the effect of the atmosphere on aircraft at different altitudes, etc. The division based on the variation of the air temperature with altitude is used most commonly in the meteorological literature.According to a publication of the agrological commission of the World Meteorological Organization (WMO) in 1961, the Earth’s atmosphere, is divided into five main layers: the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere. These layers are bounded by four thin transition regions: the tropospause, the stratospause, the mesospause, the thermospause .The troposphere is the lower layer of the atmosphere between the Earth’s surface and the tropopause. The temperature drops with increasing height in the troposphere, at a mean rate of 6.5 ℃per kilometer (lapse rate). The upper boundary of the troposphere lies at a height of approximately 8 to 12 km in the polar and troposphere contains about 75% of the total mass of atmospheric air, while in the tropics it contains about 90%. The tropoause is an intermediate layer in which either a temperature in version or an isothermal temperature distribution is observed.The stratosphere is the atmospheric layer above 就像海洋中的鱼一样,人类被局限在大气中一个非常狭窄的层次之内。

虽然地球的大气层在水平方向上的不均匀性比在垂直高度上的不均匀性要小得多。

但它确确实实在水平和垂直两个方向上都是不均匀的。

人们设计了各种各样的标准来划分大气的层次。

有的基于垂直温度廓线的性质，有的根据空气在不同高度上的大气成分，有的根据大气在不同高度上对飞机的影响来划分等等。

根据空气温度随高度的变化来划分（大气的层次）是气象文献中用得最普遍的一种划分方法。

根据1961年世界气象组织大气学委会公布的标准，地球大气被划分为5个主要层次：对流层，平流层，中层，热成层以及外逸层。

这些层次之间邻接着4个浅薄的过渡区域：对流层顶，平流层顶，中层顶以及热成层顶。

对流层是介于地球表面和对流层顶之间的大气低层．在对流层中，温度以平均6.5℃/km 的递减率随高度的增加而降低，其上边界在极地和中纬度地区大约位于8—12Km的高度，在热带地区大约位于16-18Km的高度。

在极地和中纬度，对流层包含了大气层中空气质量的75%左右，然而在热带地区，包含了大约90%。

对流层顶是一个中间层次，据观测，其温度是逆温或是等温分布。

the troposphere. In the stratosphere the temperature either increases with height or remains nearly constant. In the lower part of the stratosphere (up to approximately 20 km above the Earth’s surface) the te mperature is practically constant (about －56 ℃). While further up the temperature increases with altitude at a rate of about 1 ℃/km at heights of 20 to 30 km and about 2.8 ℃/km at altitudes from 32 to 47 km. Under the standard conditions the temperature at the 47 km level is normally -2.5 ℃.This increase in temperature with height is due to the absorption of UV solar radiation by ozone molecules. It should be noted that about 99% of the total mass of atmospheric air is concentrated in the troposphere and stratosphere, which extend up to an latitude of 30 or 35 km. The stratopause is an intermediate layer between the stratosphere and the mesosphere (in the altitude region from 47 to 52 km ), in which the temperature remains constant at about 0℃.The thermosphere is the atmospheric layer above the mesopause. The temperature in this layer increases with increasing altitude, reaching about 2000 ℃at about 450km, the mean height of the upper boundary of the thermosphere. The temperature increase in this layer is mainly caused by the absorption of UV solar radiation by oxygen molecules, which dissociate as a result of this.The exosphere is the furthest out and the least studied part of the upper atmosphere. It is located above 450km altitude. The air density in the exosphere is so low that atoms and molecules can escape from it into interplanetary space.Finally, along with the above division of the atmosphere, we will also make use of a division 平流层是位于对流层之上的大气层，在平流层中，温度或是随高度增加，或是几乎保持定常。

在平流层的低层（直到地球表面之上大约20Km）温度实际是一个常数（大约-56 ℃）。

然而再向上，大约20Km~30Km 的高度，温度随高度以 1 ℃/km的速度增加，从30Km~47Km高度上，以2.8 ℃/km 的速率增加。

在标准情况下，47Km高度上正常的温度是-2.5摄氏度。

温度随高度的增加是由于太阳辐射的紫外线被臭氧分子吸收的缘故。

值得一提的是大气层中空气总质量的99%都集中在对流层和平流层中，一直伸展到30-35Km的高度上。

平流层顶位于平流层和中间层的中间层（大约从47-52Km的高度上），平流层顶温度保持定常，约为0摄氏度。

热成层是位于中层顶上的大气层，其温度随高度的增加而增加，到热成层上边界的平均高度，即大约在450Km高度上，达到大约2000摄氏度。

该层中温度的增加主要是因为太阳辐射的紫外线被氧分子吸收，分解所致。

外逸层是最远的，也是研究最少的大气的上层部分。

它位于大约450Km的高度上。

外逸层中空气的密度非常小，以致原子和分子都能逃逸到星际空间。

based on the extent of atmospheric interaction wit h the Earth’s surface. According to this principe,the atmosphere is usually divided into a so called boundary layer (sometimes also called the friction layer) and the free atmosphere. The atmospheric boundary layer(up to 1 or 1.5 km) is influenced consider ably by the Earth’s surface and by eddy-viscosity forces. At the same time, we can neglect, as a first approximation, the influence of eddy-viscosity forces in the free atmosphere.Of all the above atmospheric layers, only the troposphere(especially its boundary layer) is characterized by a marked instability of the vertical distribution of the meteorological parameters. It is in this layer that both temperature inversions and superadiabatic temperature variations with height are observed.The Earth’s atm osphere is a mixture of gases and aerosols, the latter being the name given to a system comprised of small liquid and solid particles distributed in the air.Air is not a specific gas :rather, it is a mixture of many gases. Some of them, such as nitrogen, oxygen, argon, neon, and so on, may be regarded as permanent atmospheric components that remain in fixed proportions to the total gas volume. Other constituents such as water vapor, carbon dioxide, and ozone vary in quantity from place to place and form time to time.The principal sources of nitrogen, the most abundant constituent of air, are decaying from agricultural debris, animal matter, and volcanic eruption. On the other side of the ledger, nitrogen is removed from the atmosphere by biological processes involving plants and sea life. 最后，除了以上对大气的划分以外，我们也可以根据大气和地面的相互作用得到另一种分法。