- 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, ...
That function of position Φ the negative gradient of which is the (static) electric field:
<center>[[File:ams2001glos-Ee19.gif
Industry:Weather
The square of the amplitude of the (complex) Fourier transform of an aperiodic function.
Thus, if f(t) is the given function, its Fourier transform is
<center>[[File:ams2001glos-Ee21.gif
Industry:Weather
1. The covariance between two variables, associated with turbulent motions.
For example, if the overbar represents a mean value, and the prime denotes a deviation from the mean, then
<center>[[File:ams2001glos-Ee1.gif
Industry:Weather
The rate of transfer of a conservative fluid property through a surface by turbulent eddies.
In the case of an unchanging mean state, the eddy flux of a property ''S'' in the ''z'' direction is expressed by
<center>[[File:ams2001glos-Ee2.gif
Industry:Weather
The difference between the mean velocity of fluid flow and the instantaneous velocity at a point.
For example,
<center>[[File:ams2001glos-Ee7.gif
Industry:Weather
The difference between the mean velocity of fluid flow and the instantaneous velocity at a point.
For example,
<center>[[File:ams2001glos-Ee7.gif
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
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
1-نفس الإشارة. 2-وبوجه عام، أي طبقة في الغلاف الجوي الذي يوجد حد أقصى لتركيز الأوزون.
Industry:Weather
The rate of conversion of turbulence into heat by molecular viscosity.
Defined as
<center>[[File:ams2001glos-De30.gif
Industry:Weather
