Atmospheric chemistry of meteoric metals.
Atmospheric chemistry of meteoric metals.
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DOI：
10.1021/cr0205309
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发表时间：
2003-10
期刊：
影响因子：
62.1
通讯作者：
J. Plane
中科院分区：
文献类型：
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作者：
J. Plane
审查的主题是从地球大气层70至120公里高度流星体上烧蚀的金属的大气化学。在描述许多不寻常的现象，从这个外星输入的材料，审查将开始一般性的介绍，这一地区的大气化学和物理。这篇介绍将相当详细，因为许多读者，甚至是相当一部分大气化学家，对平流层以上的大气区域知之甚少。图1a是从0到120公里的大气温度分布图，历史上一直用于定义大气区域。从大约75公里延伸到110公里的区域通常被称为中间层/低热层区域。MLT特别令人感兴趣，因为它形成了大气层和空间之间的边界，并受到来自上方的太阳电磁辐射和太阳风形式的高能输入，以及来自下方的重力波，潮汐和行星波形式的几乎等量的能量。中间层始于约50公里处的平流层顶，这一区域的特点是平流层臭氧吸收200纳米以上的太阳紫外线辐射而加热，造成局部温度最高。图1b是北方仲夏期间的高度-纬度温度图。这表明，温度随着高度的增加而降低，通过中间层到达中间层顶（根据季节的不同，在85-100公里之间），这实际上是地球上最冷的区域。在中层顶之上，热层开始形成。波长低于180 nm的极端紫外线和X射线辐射的吸收，主要是由O2吸收，导致随着海拔高度迅速变暖。热层的温度达到400-1000 K，但应该注意的是，这些是动力学温度;分子的振动（有时是旋转）模式通常不处于局部热力学平衡（LTE），因为在110 km以上的低压（< 10-7 bar）。
The subject of this review is the atmospheric chemistry of the metals that ablate from meteoroids at altitudes between 70 and 120 km in the Earth’s atmosphere. Before describing the many unusual phenomena that arise from this extraterrestrial input of material, the review will begin with a general introduction to the chemistry and physics of this region of the atmosphere. This introduction will be reasonably detailed because many readers, indeed even a significant fraction of atmospheric chemists, have little knowledge of the atmospheric regions above the stratosphere. Figure 1a is a temperature profile of the atmosphere from 0 to 120 km, which historically has been used to define the regions of the atmosphere. The region extending from about 75 to 110 km is often referred to as the mesosphere/lower thermosphere (MLT) region. The MLT is of particular interest because it forms the boundary between the atmosphere and space and is subject to high-energy inputs from above in the form of solar electromagnetic radiation and the solar wind, and a nearly equivalent amount of energy from below in the form of gravity waves, tides and planetary waves. The mesosphere begins at the stratopause around 50 km, a region characterized by a local temperature maximum caused by heating due to stratospheric ozone absorbing solar UV radiation above 200 nm. Figure 1b is a height-versus-latitude plot of temperature during mid-summer in the northern hemisphere. This shows that the temperature decreases with height through the mesosphere up to the mesopause (85-100 km depending on season), which is actually the coldest region of the planet. Above the mesopause the thermosphere begins. The absorption of extreme UV and X-ray radiation at wavelengths below 180 nm, mostly by O2, leads to a rapid warming with altitude. Temperatures in the thermosphere reach 400-1000 K, although it should be noted that these are kinetic temperatures; the vibrational (and sometimes rotational) modes of molecules are not usually in local thermodynamic equilibrium (LTE) because of the low pressure (< 10-7 bar) above 110 km.