- 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, ...
A theoretical concept in analogy to Laplace's oceanic equilibrium tide; roughly, the form of the atmosphere determined solely by gravitational forces in the absence of any rotation of the earth relative to the sun.
Industry:Weather
1. (Also known as the universal equilibrium range. ) The range of higher-frequency eddies in the turbulence kinetic energy spectrum within which the energy cascade takes place. The equilibrium range includes the inertial subrange and lies between the range of energy- containing eddies and the viscous subrange. 2. That part of the ocean wave spectrum where a balance exists among the input of energy from the wind, the transfer of energy to different wave components (nonlinear wave–wave interactions) and the dissipation of energy due to breaking.
Industry:Weather
The boundary on a glacier between the ablation area and accumulation area. No net mass is gained or lost at this location. In the absence of superimposed ice, this line is equal to the snow line at the end of the mass balance year.
Industry:Weather
Drawdown of the water table or piezometric head when a steady-state condition has been reached.
Industry:Weather
1. In mechanics, a state in which the vector sum of all forces, that is, the acceleration vector, is zero. In hydrodynamics, it is usually further required that a steady state exist throughout the atmospheric or fluid model. The equilibrium may be stable or unstable with respect to displacements therefrom. See also hydrostatic equilibrium, geostrophic equilibrium, instability. 2. In thermodynamics, any state of a system that would not undergo change if the system were to be isolated. Processes in an isolated system not in equilibrium are irreversible and always in the direction of equilibrium.
Industry:Weather
In mathematical modeling of climate, the equilibrium climate achieved after allowing the climate system sufficient time to completely adjust to a change in external forcing.
Industry:Weather
A statistically stationary state of climate; in mathematical modeling of climate, the nondrifting state eventually reached under some specified external “boundary” conditions (such as the trace greenhouse gas concentrations in the atmosphere, the solar constant, and, perhaps, the geographical distributions of vegetation and glacial ice).
Industry:Weather
Equality of deviation (or departure) from a normal value. Lines or curves of equideparture are called isametrics. They may be drawn on a map to show, for example, areas where the atmospheric pressure is above or below normal by the same amount.
Industry:Weather
Planetary waves propagating parallel to the equator, the meridional structures of which are trapped in the vicinity of the equator. Included are equatorial Kelvin waves, Rossby waves, mixed Rossby–gravity waves, and gravity waves. The equatorial trapping is due to the variation of the Coriolis parameter and the fact that the parameter itself is zero at the equator. See also equatorial waveguide.
Industry:Weather
The westerly winds occasionally found in the equatorial trough and separated from the midlatitude westerlies by the broad belt of easterly trade winds. As the air flow in the lower atmosphere is mostly easterly in and about the equatorial trough, the existence of westerlies on mean charts in some areas has been a subject of much interest and speculation. In some regions, this abnormality can be explained as the result of limited areas of west winds on the equatorward side of frequent westward moving cyclones in the equatorial trough. Elsewhere (notably over the Indian Ocean during the Northern Hemisphere summer), the equatorial westerlies may result from the deflection of Southern Hemisphere air as it flows northward across the geographical equator as part of the monsoon. Equatorial westerlies can also be induced on the western side of a large scale localized heating near the equator, such as in the maritime continent.
Industry:Weather
