- 行业: Weather
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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
A measure of the ability of a halocarbon source gas to destroy stratospheric ozone, determined relative to an equal mass of chlorofluorocarbon-11. The ozone-depleting potential is usually determined by examining the effects on the ozone layer of the addition of the compound under investigation using atmospheric models.
Industry:Weather
A radiosonde equipped with an instrument to measure the atmospheric concentration of ozone (O<sub>3</sub>).
Industry:Weather
Popular expression, referring to the fact that the strong absorption of ultraviolet light by stratospheric ozone limits the amount of dangerous radiation reaching the earth's surface.
Industry:Weather
A plot in which contours of tropospheric ozone are plotted as a function of the active nitrogen mixing ratio versus total hydrocarbon mixing ratio. Regions where ozone production is limited by the availability of nitrogen oxides or by hydrocarbons are readily apparent in such a plot.
Industry:Weather
A characteristic severe depletion of stratospheric ozone that occurs each spring over the Antarctic continent. The depletion is caused by the catalytic destruction of ozone by chlorine, released from fluorocarbons and activated by the presence of polar stratospheric cloud particles in the extreme cold of the Antarctic stratosphere.
Industry:Weather
A nearly colorless gas, formula O<sub>3</sub>, molecular weight 48, that appears blue in the condensed phase or at high concentration, with a characteristic odor like that of weak chlorine. It is formed in the reaction between atomic oxygen and molecular oxygen:. It is a very strong absorber of ultraviolet radiation, and the presence of the ozone layer in the upper atmosphere provides an ozone shield that prevents dangerous radiation from reaching the earth's surface and allows the existence of life in its present forms. Ozone, produced by photochemical reactions, is found at all altitudes in the atmosphere. The total amount of ozone in the atmosphere would correspond to less than 1 part per million if uniformly distributed, or a column amount of about 3 mm if compressed to sea level pressure. In the troposphere, it is regarded as a pollutant, and its presence in high concentrations can lead to respiratory stress and crop damage. Ozone is an important component of photochemical smog and can also be formed locally by the action of electrical discharges on the air. Ozone in the free troposphere often results from downward transport from the stratosphere. In the stratosphere, ozone is formed following the absorption of radiation by molecular oxygen. Its mixing ratio there can reach several parts per million, and the temperature inversion characteristic of the stratosphere is due to the strong absorption of energy by ozone molecules in this region. In the stratosphere, ozone is destroyed predominantly by catalytic cycles involving free radicals, many of which are formed as products of human activity. Ozone has several radiation absorption bands that are atmospherically important: the very intense Hartley band, between 200 and 300 nm, which is responsible for much of the heating of the upper atmosphere; the Huggins bands, between 320 and 360 nm; the Chappuis bands, between 450 and 650 nm; and infrared bands, centered at 4. 7, 9. 6, and 14. 1 μm. All the above bands have been used for the detection of ozone using various remote sensing techniques. Absorption by ozone in the infrared is responsible for its effectiveness as a greenhouse gas. See Dobson unit.
Industry:Weather
Regions of the electromagnetic spectrum in which molecular oxygen, O<sub>2</sub>, absorbs solar radiation but plays an insignificant role in the direct heating of the atmosphere. This band is strong between 0. 13 and 0. 17 μm, and is of special importance in the absorption of ultraviolet radiation.
Industry:Weather
(Symbol O. ) An element, atomic number 8, atomic weight 16. 0; molecular oxygen, formula O<sub>2</sub>, molecular weight 32, is the second most abundant species in the atmosphere, with an abundance of approximately 21% at sea level. The atmospheric abundance of O<sub>2</sub> remains fairly constant up to about 80 km, above which substantial photodissociation to atomic oxygen occurs. Oxygen is a prerequisite to almost all forms of terrestrial life. Oxygen was probably released from minerals such as carbonates resulting in the evolution from a reducing to an oxidizing atmosphere. The general tendency is for reduced emissions from the earth's surface to be oxidized to simpler, oxygen-containing species. Atomic oxygen is formed in the photolysis of molecular oxygen, O<sub>2</sub>; ozone, O<sub>3</sub>; or nitrogen dioxide, NO<sub>2</sub>, in the atmosphere. Below about 40 km, its predominant fate is recombination with molecular oxygen to form ozone. Above that altitude it can participate in other chemical reactions, which may lead to ozone destruction. Both molecular and atomic oxygen have low-lying electronically excited states that are important in the atmosphere. The <sup>1</sup>Δ and <sup>1</sup>Σ states of O<sub>2</sub> are relatively long- lived, and fluorescence from these states contributes to the airglow. The O<sup>1</sup>D state of atomic oxygen, formed in ozone photolysis, reacts to form the hydroxyl radical, which is the primary oxidant in the atmosphere.
Industry:Weather
Homogeneous on the scale of the wavelength of the electromagnetic radiation of interest. Pure liquid water is optically homogeneous over the visible spectrum because one cubic wavelength of water contains many molecules, whereas a cloud of water droplets is not optically homogeneous. Optical homogeneity is more general than transparency, usually restricted to visible wavelengths. A body is said to be transparent if it transmits images. Optical homogeneity is necessary for transparency but not sufficient. A sufficiently thick sample of an absorbing optically homogeneous material would be described as opaque rather than transparent.
Industry:Weather
Smooth on the scale of the wavelength of the electromagnetic radiation of interest. No surface is absolutely smooth, if for no other reason than matter is composed of molecules in motion. An approximate criterion for smoothness is the Rayleigh criterion. A surface is reckoned to be optically smooth if ''d'' < λ/(8 cos θ), where ''d'' is the surface roughness (e.g., root-mean- square roughness height measured from a reference plane), λ is the wavelength of the incident illumination, and θ is the angle of incidence of this illumination. Thus, a surface that is smooth at some wavelengths is rough at others, or that is rough at some angles of incidence and smooth at others (e.g., near-grazing angles).
Industry:Weather
