- 行业: Weather
- Number of terms: 60695
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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 thin board or other lightweight substance used as a means of identifying the surface of snow or ice that has been covered by a more recent snowfall.
Industry:Weather
1. Ice crystals (usually cup-shaped, faceted crystals) of low strength formed by sublimation within dry snow beneath the snow surface; a type of hoarfrost. Associated with very fast crystal growth under large temperature gradients. This is one way in which firn formation may begin. Depth hoar is similar in physical origin to crevasse hoar. 2. Hoarfrost composed of crystals that have built up a three-dimensional complex of faceted, rather than rounded, crystals.
Industry:Weather
Water temporarily retained in puddles, ditches, and other depressions in the surface of the ground, and eventually evaporated or infiltrated; the small-scale counterpart of closed drainage.
Industry:Weather
The angle between the horizon and a point below, measured along the arc that passes through the point in question and is perpendicular to the horizon. The depression angle is the zenith distance of the point in question minus 90°. Compare azimuth, elevation angle, zenith distance.
Industry:Weather
A crystal, particularly a planar ice crystal, with its macroscopic form (crystal habit) characterized by intricate branching structures of a treelike nature. Dendritic ice crystals possess hexagonal symmetry, and tend to develop when a crystal grows by vapor deposition at temperatures within a few degrees of −15°C, providing saturation is close to supercooled water. Similar forms occur by ice growth into supercooled liquid water at temperatures down to −10°C. Spatial dendrites grow in three dimensions from a central frozen drop.
Industry:Weather
A solid aerosol particle that nucleates an ice crystal directly from the vapor, particularly (but not necessarily) at subwater saturation and in the absence of the bulk liquid phase. The process does not preclude an intermediate adsorbed layer (Langmuir layer) prior to nucleation.
Industry:Weather
Processes by which traces gases or particles are transferred from the atmosphere to the surface of the earth. Atmospheric deposition is usually divided into two categories, wet deposition and dry deposition, depending on the phase of the material during the deposition process. Thus, in wet deposition, the gas or particle is first incorporated into a droplet and is then transferred to the surface via precipitation. In dry deposition, the gas or particle is transported to ground level, where it is adsorbed onto a surface. The surface can be the ocean, soil, vegetation, buildings, etc. Note that the surface involved in the dry deposition may be wet or dry.
Industry:Weather
General term denoting the ratio of the cross-polarized to the copolarized signal components measured by a polarimetric radar. See circular depolarization ratio, linear depolarization ratio, elliptical depolarization ratio.
Industry:Weather
The general name for instruments used in air pollution studies for determining the amount of material deposited on a given area during a given time.
Industry:Weather
The process by which a polarized signal, for example, a radar signal, loses its original polarization as the result of scattering or of propagation through an anisotropic medium. The signal may experience a change of polarization, for example, from circular to elliptical as a result of differential attenuation or differential phase shift, or it may experience a loss of polarization, that is, become unpolarized, as a result of scattering in a random medium.
Industry:Weather
