- 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, ...
When a plane wave is incident on a uniaxial medium (an anisotropic medium with two equivalent orthogonal directions), two transmitted waves result: the ordinary ray (or wave), the phase velocity of which does not depend on its direction, and the extraordinary ray (or wave), the phase velocity of which depends on the angle it makes with the optic axis (the unique direction along which waves propagate as if the medium were optically isotropic).
Industry:Weather
The vertical coordinate in a two-dimensional system of rectangular Cartesian coordinates; usually denoted by ''y''. Also, the vertical axis of any graph. See abscissa.
Industry:Weather
Group of organic compounds containing the carboxylic group -C(O)OH, formed by the oxidation of aldehydes. Acids such as formic, acetic, and pyruvic acids are often found in air masses containing the oxidation products of organic matter. Other multifunctional acids such as oxalic and malonic acid are often found in liquid droplets. The mechanism of their formation is not fully understood at the moment. The organic acids are relatively weak and do not contribute much to the acidity of the atmospheric aerosol.
Industry:Weather
Nitrogen-containing compounds, general formula RONO<sub>2</sub> where R is an alkyl (or organic) group; formed in a minor (2%–30%) channel of the reaction of nitric oxide with the corresponding alkylperoxy radical. The extent of formation of organic nitrates in an air mass has been used as a measure of the age of the air mass. They are a reservoir species for NO<sub>x</sub>.
Industry:Weather
Organic molecules containing an oxygen–oxygen linkage, general formula ROOR or ROOH, where R is an organic group. In the atmosphere, ROOH is most commonly encountered, and the compound is an organic hydroperoxide.
Industry:Weather
Relating to mountains and mountain effects. Often refers to influences of mountains or mountain ranges on airflow, but also used to describe effects on other meteorological quantities such as temperature, humidity, or precipitation distribution. A major effect is orographic lifting.
Industry:Weather
Mountain clouds produced by orographic lifting of moist air to saturation. Clouds formed by upslope winds are generally stratiform, those formed by mountain wave updrafts are often lenticularis-type or wave clouds, and those formed by heating, such as elevated heat source or leeside convergence effects, are generally cumuliform. Upslope and wave clouds are clouds with form and extent determined by the disturbing effects of orography upon the passing flow of air. Because these clouds are linked to the topography, they are generally standing clouds, even though the winds at the same level may be very strong. Orographic upslope clouds include stratiform cap or crest clouds and the foehn wall. Convective orographic clouds are also strongly tied to the topography. Banta (1990) finds that mountain flows, which are driven by the topography interacting with the large-scale winds and the diurnal heating cycle, “play a significant role in determining where convective cells will initiate, and often how precipitation from the showers will be distributed spatially. . . They regulate not only the location of storm initiations, but also the timing. ”
Industry:Weather
Fog formed as moist air blows up a mountain slope and becomes saturated. Flow can result from large-scale upslope winds or thermally forced upslope (anabatic) winds. See anabatic wind, orographic cloud.
Industry:Weather
A distortion of an isobar or isobars (surface or upper level) due to a mountain range or other obstruction.
Industry:Weather
Ascending air flow caused by mountains. Mechanisms that produce the lifting fall into two broad categories: 1) the upward deflection of horizontal larger-scale flow by the orography acting as an obstacle or barrier; or 2) the daytime heating of mountain surfaces to produce anabatic flow along the slopes and updrafts in the vicinity of the peaks. The first category includes both direct effects, such as forced lifting and vertically propagating waves, and indirect effects, such as upstream blocking and lee waves. Even though this term strictly refers only to lifting by mountains, it is sometimes extended to include effects of hills or long sloping topography. When sufficient moisture is present in the rising air, orographic fog or clouds may form.
Industry:Weather
