- 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, ...
The property of turbulence within one air mass that occurs at some times and some places and does not occur at intervening times or places. Whereas the classical theory of homogeneous turbulence relies on the assumption that the turbulence energy dissipation rate ε is constant in space, in reality ε is not always constant. Those inhomogeneities may lead to intermittent turbulence. To predict a turbulent or nonturbulent (laminar) behavior within an air mass properly, the complete vertical profiles of either the virtual potential temperature or the buoyancy must be known. Turbulence is often intermittent in the stable boundary layer (e.g., nocturnal) and in the entrainment zone capping the convective mixed layer (e.g., daytime).
Industry:Weather
The process by which a layer of ice (icing) builds up on solid objects that are exposed to freezing precipitation or to supercooled fog or cloud droplets. At the earth's surface this usually refers to glaze formation, and the amount of ice can be roughly measured by an ice-accretion indicator. For airborne objects, ice accretion refers to any type of aircraft icing. See accretion.
Industry:Weather
The portion of the UV spectrum of molecular oxygen (O2) between 200 and 240 nm. The absorption results from forbidden electronic transitions from the molecular ground state to a number of electronically excited states. Photolysis of O2 is dominated by the Herzberg continuum throughout the stratosphere.
Industry:Weather
The process by which a substrate is split to form two end products by the intervention of a molecule of water, or the reaction of a substrate with a water molecule.
Industry:Weather
The physical location of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and is not always correctable. The purpose of the instrument shelter is to provide as good an exposure as possible.
Industry:Weather
The pressure in a fluid in hydrostatic equilibrium. Compare static pressure; see also hydrodynamic pressure.
Industry:Weather
The potential difference between the conductive earth and the conductive upper atmosphere, approximately +250 kV. This voltage difference is maintained by worldwide cloud electrification. Most of the 250 kV is realized well below the formal ionospheric height of maximum ionization because of the rapid increase of electrical conductivity with height in the atmosphere.
Industry:Weather
The points on the radiation pattern of an antenna where the transmitted power is one-half that of the maximum, both measured at the same range. The maximum usually lies along the axis of the beam, and therefore the angle subtended at the antenna by the half-power points is used to define a beam width. The beam width need not be the same for all planes through the axis of the beam.
Industry:Weather
The photometric equivalent of irradiance. Illuminance is obtained by integrating spectral irradiance weighted by luminous efficiency over the visible spectrum. Compare luminance.
Industry:Weather
The outside part of convective thermals that experience mixing with the ambient environment. These thermals are somewhat cylindrically shaped in the convective boundary layer rather than bubble-shaped as was proposed by some classical theories. The inside of a thermal is called a protected core and is usually not contaminated with entrained environmental air.
Industry:Weather
