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 gaous 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.诗朗诵稿
Various criteria have been devid for dividing the atmosphere into layers. This division can be bad on the nature of the vertical temperature profile, on the gaous composition of the air at different altitudes, and the effect of the atmosphere on aircraft at different altitudes, etc. The division bad on the variation of the air temperature with altitude is ud 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. The layers are bounded by four thin transition regions: the tropospau, the stratospau, the mesospau, the thermospau .
The troposphere is the lower layer of the atmosphere between the Earth’s surface and the tropopau. The temperature drops with increasing height in the troposphere, at a mean rate of 6.5 ℃per kilometer (lap 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 tropoau is an intermediate layer in which either a temperature in version or an isothermal temperature distribution is obrved.
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 increas 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 increas 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 increa 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 stratopau 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 mesopau. The temperature in this layer increas with increasing altitude, reaching about 2000 ℃at about 450km, the mean height of the upper boundary of the thermosphere. The temperature increa in this layer is mainly caud 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 u 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。
bad 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 obrved.
The Earth’s atm osphere is a mixture of gas and aerosols, the latter being the name given to a system comprid of small liquid and solid particles distributed in the air.
Air is not a specific gas :rather, it is a mixture of many gas. 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 d
ioxide, 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 process involving plants and a 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。根据此原则，⼤⽓通常被划分为所谓的边界层（有时也称摩擦层）和⾃由⼤⽓。地球表⾯和涡度粘滞⼒对⼤⽓边界层（知道1-1.5Km）有相当⼤的影响；同时，作为⼀级近似，在⾃由⼤⽓中我们可以忽略涡度粘滞⼒的影响。
以上这些⼤⽓层中，只有对流层（尤其是边界层）中⽓象参数的垂直分布具有显著的不稳定性的特征。⼈们观测到该层中存在逆稳和温度随⾼度超绝热变化。
地球⼤⽓是⽓体和⽓溶胶的混合物，所谓的⽓溶胶指的是由分布在空⽓中的微⼩的液体和固体颗粒组成的系统。
空⽓不是⼀种特殊的⽓体，⽽是由许多⽓体混合成的。其中⼀些⽓体，如，氮，氧，氩，氖等，作为空⽓的永久组成成分，总是以固定的⽐例存在于⼤⽓中。其中⼀些成分，如，⽔汽，⼆氧化碳和臭氧的含量是随时间和地点的不同⽽改变。
氮在空⽓中的含量最多，其中主要来源是腐烂的作物残渣，动物⼫体及⽕⼭爆发。另⼀⽅⾯，⼤⽓中的氮⼜为包括植物和海洋⽣物在内的⽣物过程的所消耗。
To a lesr extent, lightning and high
temperature combustion process convert nitrogen gas to nitrogen compounds that are washed out of the atmosphere by rain or snow. The destruction of nitrogen is in the atmospheres in balance with production.
Oxygen, a gas crucial to life on Earth, has an average residence time in the atmosphere of about 3000 years. It is produced by vegetation that, in the photosynthetic growth process, takes up carbon dioxide and releas oxygen. It is removed from the atmosphere by humans and animals, who respiratory systems are just the rever of tho of the plant communities. We inhale oxygen and exhale carbon dioxide.
Oxygen dissolves in the lakes, rivers and oceans, where it rves to maintain marine organisms. It is also consumed in the process of decay of organic matter and in chemical reactions with many other substances. For example, the rusting of steel involves its oxidation.
From the human point of view, the scarce, highly variable gas are of great importance. The mass of water vapor, that
is,H2O in a gaous state, in the atmosphere is relatively small and is added to and removed from the atmosphere relatively fast. As a result ,the average residence time of water vapor is only 11 days. Water vapor is the source of rain and snow, without which we could not survive.
From common experiences it is well known that the water vapor content of air varies a great deal. In a dert region the concentration of water vapor can be so low as to reprent only a tiny fraction of the air volume. At the other extreme, in hot, moist air near a level, say over an equatorial ocean, water vapor may account for as much as perhaps 5 percent of the air volume. 闪电及⾼温燃烧过程将少量氮⽓转化为氮化物，再由⾬雪带出⼤⽓。⼤⽓中氮的损耗和产⽣是平衡的。
地球⽣命必不可少的⽓体——氧⽓，在⼤⽓中已有三千年左右的时间了。氧⽓由植物释放出来，即通过植物的光合作⽤吸收⼆氧化碳，释放氧⽓，被⼈类和动物所吸收，⼈和动物的呼吸系统同植物的呼吸系统恰恰相反。我们吸进氧⽓呼出⼆氧化碳，
氧⽓溶进湖，河和海洋中，来维持海洋⽣物的⽣存。在同其他物质发⽣化学反应或是有机物的腐烂过程也要消耗氧⽓，⽐如说钢铁⽣锈就涉及到氧化过程。
对⼈类来说，稀少的，多变的⽓体是⾮常重要的。⽔汽，即⽔的⽓态，在⼤⽓的含量是⽐较稀少的，⽽且它的⽣成和消耗是⽐较快的。因此，⽔汽在⼤⽓中存在的平均时间只有11天，⽔汽是⾬雪得源泉，没有⽔汽我们就不能⽣存。
吴的组词
众所周知，⽔汽在⼤⽓中的含量是多变的，在沙漠地带，⽔汽含量⾮常低，只占空⽓总量的很少的⼀部分，相反，在其他地区，特别是潮湿的热的海⾯上，或者⾚道洋⾯上，⽔汽可以占到⼤⽓总量的5%左右。
There are large variations of atmospheric water vapor from place to place and from time to time, but the total quantity over the entire Earth is virtually constant. The same can not be said about carbon dioxide (co2).The concentration of this spar but important gas has been increasing for the last hundred years or so.
Carbon dioxide is added to the atmosphere by the decay of plant material and humus in the soil ,and by the burning of fossil fuels: coal, oil, and gas. The principal sinks of co2 are the oceans and plant life that us co2 in photosynthesis.
In the middle 1980s,atmospheric chemists were still debating about the effects on atmospheric co2 of burning, harvesting and clearing of forests. The oceans take up large amounts of co2,about half th
e amount relead by fossil fuel combustion. It is expected that this fraction will diminish with the passing decades whereas the total mass of co2 relead will increa ,at least through the early part of the next century.
During the 1980s atmospheric co2 was accumulating at a rate of about 1 part per million (ppm)of air per year, but it is expected to increa more rapidly in decades to come .In1983 it averaged about 340 ppm of air.感恩节吃火鸡
Ozone(o3),another important, highly variable gas, occurs mostly at upper altitudes ,but it is also found in urban localities having a great deal of industry and automotive traffic and a generous supply of sunshine. In cities such as Los Angeles, ozone concentration may be more than 0.1ppm in extreme cas. Most atmospheric ozone concentrations often exceed
1.0ppm and may be large as 10 ppm.
They vary greatly with latitude, ason ,time of day, and weather patterns. The high-altitude 尽管⼤⽓中的⽔汽的含量随时间和地点的不同有很⼤的变化，但它在整个地球上的总量实际上是不变的。⽽⼆氧化碳却不是这样的。在过去的⼀百年⾥，这种稀少的但却很重要的⽓体的含量⼀直在上升
腐烂的植物，⼟壤中的腐殖物以及燃烧煤，⽯油，天然⽓，等化⽯燃料都能向⼤⽓释放⼆氧化碳。⼆氧化碳主要的汇是海洋和植物，植物需要⼆氧化碳进⾏光合作⽤，
⼆⼗世纪⼋⼗年代中期，⼤⽓化学家就森林的燃烧，砍伐对⼤⽓中⼆氧化碳产⽣的影响进⾏了争论。海洋吸收了⼤量的⼆氧化碳，⼤约占化⽯燃料燃烧释放的⼆氧化碳总量的⼀半。⼈们预测，往后的⼏⼗年，这部分吸收量将会逐步减少，⽽释放的⼆氧化碳的总量则会增加，这种情况⾄少会延续到下个世纪初。
⼆⼗世纪⼋⼗年代，⼤⽓中的⼆氧化碳，每年以空⽓的百万分之⼀的速度增加。但是，据预测，这种增加速度在未来的⼏⼗年中还要更快⼀些。1983年，其含量平均为空⽓的百万分之340。
另⼀种重要多变的⽓体-------臭氧（O3），多存在于⾼层⼤⽓中，但在交通拥挤，有许多⼯⼚或是充⾜阳光照射的地区也有臭氧存在。像洛杉矶这样的城市，O3最多时可超过0.1ppm。⼤⽓中臭氧的含量⼤多在 1.0——10ppm之间。
它们随⾼度，季节，时间，天⽓状况的不同⽽不同。⾼层⼤⽓中的O3 层是由光化学反
第⼀课⼤⽓的结构和组成
Unit Two: Frontogenesis and frontal characteristics
ozone layer is maintained by photochemical reactions. The ozone layer is important becau, by absorbing UV radiation in the upper atmosphere, it reduces the amount reaching the surface of the Earth, exposure to incread dos of ultraviolet rays would cau more vere sunburns and increa the risk of skin cancers. Biologists indicate that a substantial increa in UV radiation could also affect other components of the biosphere. Certain gages, if they exist in sufficiently high concentrations, can be toxic to people, animal and plant life. For example, when ozone occurs in high concentrations, it is toxic to biological organisms. This does not happen often, but in heavily polluted localities such as Los Angeles, ozone near the ground sometimes is sufficiently abundant to cau leaf damage to certain plant species. Very large quantities of potentially hazardous gas are introduced into the atmosphere as a result of human activities. Air pollutants are emitted from furnaces, factories, refineries, and engines, particularly automobile engines. All the things and others like them burn fossil fuels: coal, oil, gasoline, and kerone. In the process they emit gas and smoke particles that may spend a great deal of time in the atmosphere reacting with other substances and causing the formation of toxic compounds. The most widespread and potentially hazardous gaous pollutants are carbon monoxide ,sulfur dioxide, nitrogen oxide, and hydrocarbons. The last of the compounds comes from vaporized gasoline and other petroleum products.
警钟应造成的。臭氧层之所以重要，是因为它通过吸收上层⼤⽓紫外线辐射，从⽽减少紫外线到达地⾯的总量，接受紫外线照射的时间越长，就越容易造成严重的灼伤，从⽽增加⽪肤癌的危险。
⽣物学家指出，紫外线过度的增加还会影响⽣物圈中的其它组成成分。
有些⽓体，如果浓度过⾼，对⼈，动物及植物⽣命可能有害，⽐如，O3浓度过⾼会对⽣物有机体造成危害。虽然这种情况不常发⽣。但洛杉矶这样污染严重的城市，有时接近地⾯的O3含量变得⾜以毁坏某些植物表⾯的叶⽚。
⼈类活动将⼤量具有潜在危险的⽓体带⼊⼤⽓。⼤型锅炉，⼯⼚，炼油⼚和发动机，特别是汽油发动机排放出空⽓污染物。
所有这些场所以及其它特别类似场所：燃烧煤，⽯油，汽油，煤油等化⽯燃料，在燃烧过程中，它们向空⽓中排放⽓体或烟尘颗粒，这些颗粒经过相当长的时间⼜和空⽓中其他成分发⽣反应，形成有毒的化合物。
分布最⼴泛的，⽽且潜在危险最⼤的⽓体污染物是⼀氧化碳，⼆氧化硫，氧化氮和碳氢化合物。这些化合物最终来源于蒸发的汽油和其他⽯油产物。
第⼆课锋⽣和锋的特征
The first real advance in our detailed understanding of mid-latitude weather variations was made with the discover that many of the day-to-day changes are associated with the formation and movement of boundaries, or fronts, between different air mass.
Obrvations of the temperature, wind directions, humidity and other physical phenomena during unttled periods showed that discontinuities often persist between impinging air mass of differing characteristics.
The term “front”, for the surfaces of air mass conflict, was a logical one propod during the First World War by a group of meteorologists working in Norway, and their ideas are still an integral part of most weather analysis and forecasting particularly in middle and high latitudes.
1. Frontal waves
itf网球It was obrved that the typical geometry of the air mass interface, or front, rembles a wave from. Similar wave patterns are, in fact, found to occur on the interface between many different media, for example, waves on a surface, ripples on beach sand, aeolian sand dunes, etc.
Unlike the wave forms, however, the frontal waves in the atmosphere are commonly unstable: that
is, they suddenly originate, increa in size, and then gradually dissipate. Numerical model calculations show that, in middle latitudes waves in a baroclinic atmosphere are unstable if their wavelength exceeds a few thousand kilometers. Frontal wave cyclones are typically 1500-3000 km in wavelength. 锋⽣
随着许多与不同⽓团之间的边界(锋⾯)形成与运动相联系的逐⽇变化被揭露之后，我们对中纬度天⽓变化的详细了解才取得了⾸次真正意义上的进步。
在这些问题未解决之前，对温度，风向，湿度和其他去理现象的观测表明具有不同特征⽽⼜紧密接触的⽓团之间经常存在不连续性。
这些不同⽓团之间交会的⾯——锋⾯，是第⼀次世界⼤战时期由在挪威⼯作的⼀批⽓象学家提出的⼀个逻辑词汇。他们的想法在⼤多数天⽓分析和预报中，尤其是在中，⾼纬度仍是⼀个完整的部分。
1.锋波
最长的地名我们观测到⽓团的交界⾯即锋⾯是⼀种典型的⼏何状，类似于⼀种波的形成。实际上，相似的波形也出现在许多不同介质的交界⾯，例如，海洋表⾯的波，沙滩上的涟漪和风吹成的沙丘等等。
然⽽，并不象这些波形，⼤⽓中的锋⾯通常是不稳定的，也就是说，它们突然⽣成，发展，然后逐渐
消散。数值模式计算表明，在中纬度斜压⼤⽓中，如果锋波波长超过⼏千公⾥，那些锋波是不稳定的。锋波的波长通常是1500-3000km。
The initially attractive analogy between atmospheric wave systems and waves formed on interface of other media is, therefore, an insufficient-basis on which to develop explanations of frontal waves. In particular, the circulation of the upper troposphere plays a key role in providing appropriate conditions for their development and growth, as will be shown below.
2.The frontal wave depression
A depression (also termed a low or cyclone) is an area of relatively low pressure, with a more or less circular isobaric pattern. It covers an area 100-3000 km in diameter and usually has a life-span of 4-7 days.
Systems with the characteristics, which are prominent on daily weather maps are referred to as synoptic scale features.
The depression, in mid-latitudes at least, is usually associated with a convergence of contrasting air mass.
The interface between the air mass develops into a wave form with its apex located at the centre of the low-pressure area. The wave enclos a mass of warm air between modified cold air in front and fresh cold air in the rear. The formation of the wave also creates a distinction between the two ctions of the original air mass discontinuity for,
although each ction still marks the boundary between cold and warm air, the weather characteristics found in the neighborhood of each ction are very different. The two ctions of the frontal surface are distinguished by the names warm front for the leading edge of the wave and cold front for that of the cold air to the rear.
The depression usually achieves its maximum 因此，最初引起兴趣⼤⽓波动系统和其他介质交界⾯所形成的波类似的东西不适宜作为进⼀步解释锋⾯的基础。尤其是对流层上层的环流对锋波的发展和壮⼤才是引起⾄关重要的适当条件（就这⼀点），我们将在以下的论证中给出。
锋波低压
低压（⼜称低压区域⽓旋），低压（⼜称低压区域⽓旋），是⼀个有着或多或少闭合等压线的相对低压区。他们直径覆盖100-3000Km，通常有4-7天的⽣命史。
具有这些特征的系统在每⽇的天⽓图上很突出，被称为具有天⽓尺度的特点。⾄少在中纬度地区，低压通常是与相对的⽓团之间的辐合联系在⼀起的。
这些⽓团之间的交界⾯发展成波的形式，它的峰位于低压区的中⼼。锋波围住了波前变性的冷空⽓和波后新鲜冷空⽓之间的⼀团暖空⽓。锋波的形成也造成了原始空⽓团不连续的两部分之间的差异。
每⼀部分在冷暖空⽓之间具有明显的边界，每⼀部分邻近区域的天⽓特征⼗分不同。锋⾯的这两部分由名为暖锋-----波的前边缘和冷锋-----波后冷空⽓来区分。
低压通常在开始锢囚后12-24⼩时强度达到
intensity 12-24 hours after the beginning of occlusion.
外婆和鞋Frontal characteristics心灰意冷什么意思
The activity of a front in terms of weather depends upon the vertical motion in the air mass. If the air in the warm ctor is rising relative to the frontal zone the fronts are usually very active and are termed ana-fronts. Whereas sinking of the warm air relative to the cold air mass gives ri to less inactive kata-fronts.
1. The warm front
The warm front reprents the leading edge of the warm ctor in the wave. The frontal zone here has a very gentle slope, of the order 1/2°-1°, so that the cloud systems associated with the upper portion of the front herald its approach some 12 hours or more before the arrival of the surface front.
The ana-warm front, with rising warm air, has multi-layered cloud which steadily thickens and lowers towards the surface position of the front. The first clouds are thin, wispy cirrus, followed by sheets of cirrus and cirrostratus and altostratus .
The sun is obscured as the altostratus layer thickens, and drizzle or rain begins to fall. The cloud often extends through most of the troposphere and with continuous precipitation occurring is generally designated as nimbostratus. Patches of stratus may also form in the cold air as rain falling through this air undergoes evaporation and quickly saturates it.
The descending warm air of the kata-warm front greatly restricts the development of medium-and high-level clouds. The frontal cloud is mainly stratocumulus, with a limited depth as a result of the subsidence inversions in both air mass. 最⼤。锋的特征
从天⽓⽅⾯来说，锋的活跃程度依靠空⽓团的垂直运动。如果暖区中的空⽓相对锋区是上升的，那么，锋通常是⼗分活跃的，被称为上滑锋。相反，暖空⽓相对于冷空⽓团下沉的，则会产⽣不活跃的
下滑锋。
暖锋
暖锋是指锋波中暖区的前边缘。这⼉所提的锋区是⼀个⼗分轻微的坡度，量级在1/2°----1°之间，所以，与锋的上部相联系的云系在地⾯锋到来之前的12⼩时甚⾄更早就预⽰了锋的临近。
随着暖空⽓上升的上滑暖锋有多层云系，这些云系稳定的增厚，并向锋的地⾯位置下降。最开始的云⽯薄⽽缥缈的卷云，紧接着是成⽚的卷层云和⾼层云。
