- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
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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, ...
Broadcast made according to a schedule of transmissions agreed internationally or nationally.
Industry:Weather
Aviation communications code word. GENOTs are originated by the U. S. Federal Aviation Administration and appear on all teletype weather services. They carry general information of interest to airmen, forecasters, and others connected with aircraft operation and weather service. Compare NOTAM.
Industry:Weather
Based upon the available record, frequency analysis involves the choice of a frequency distribution to describe the phenomena of interest and the estimation of the parameters of that distribution, so as to obtain a description of the relationship between different values of a variable and their exceedance probability.
Industry:Weather
As waves approach the coast and move into shallow water, the sea bed affects their propagation, leading to phenomena such as wave refraction and wave breaking. The latter is easily observed on any beach; as the waves approach the beach they steepen and break. As a rule-of-thumb, waves feel the bottom when the water depth is less than approximately one-quarter of their wavelength.
Industry:Weather
As used by the U. S. Army Corps of Engineers, the period of time between the highest point and the succeeding lowest point on the time curve of cumulative degree-days above and below 32°F; the opposite of thawing season. A less rigorous, but more commonly used, definition is the number of days or months between the first day of fall or winter and the last day of the same winter or the following spring on which the air temperature is below 0°C.
Industry:Weather
Any wave that is required to fit irregularities at the boundary of a system or satisfy some impressed force within the system. The forced wave will not in general be a characteristic mode of oscillation of the system. It cannot be exhibited independently unless the system admits no free waves. A homogeneous incompressible fluid bounded by two rigid surfaces is an example of such a system. The gravity lee wave in the atmosphere is an example of mixed forced and free waves. See resonance, oscillation.
Industry:Weather
Any thunderstorm that is perceived by observers to be green. The perceptually dominant wavelength of light from green thunderstorms ranges from blue- green to yellow-green. The purity of the color is generally low and the physical mechanism that causes the green appearance is not understood. Although green clouds often occur in conjunction with severe weather, there is no evidence to support anecdotal attributions of the cause of this green to specific characteristics of severe storms, such as hail or tornadoes.
Industry:Weather
Any wave not acted upon by any external force except for the initial force that created it; a wave solution satisfying a homogeneous equation of motion and homogeneous boundary conditions. In a system with no impressed forces, a free wave has zero amplitude at the boundaries of the system. The phase speed, wavelength, etc. , of the free wave or waves are characteristics of the system. A simple example of such a wave in meteorology is a billow cloud layer over level ground. In a steady-state solution, free waves have arbitrary amplitude. These may be specified by initial conditions to determine the solution completely. A free wave on a water surface is one created by a sudden impulse, thereafter influenced only by friction, the dimensions of the basin, and the dispersive character of the water medium it moves in. Most ocean surface waves, except tidal waves, are free waves. Compare forced wave; see oscillation.
Industry:Weather
Any radar target on the ground. Such targets include buildings, mountains, hills, trees or shrubs, and automobiles, which may be detected in the main lobe or sidelobes of the antenna and may produce coherent or incoherent echoes that can interfere with the detection or quantitative measurement of weather echoes. See ground clutter.
Industry:Weather
