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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, ...
In oceanography, a current determined by the condition that the horizontal pressure gradient due to the (hydrostatic) distribution of mass balances the Coriolis force due to the earth's rotation. The gradient current corresponds to the geostrophic wind in meteorology. In practice, the distribution of density is determined by measurements of salinity and temperature at a series of depths in a number of positions. From this the geopotential topography of any isobaric surface relative to any other isobaric surface may be computed and the horizontal pressure gradient may be expressed by the geopotential slope of the isobaric surface. In this way relative isobaric surface currents are obtained, corresponding to thermal wind in meteorology. If one isobaric surface is known to be level, the absolute geopotential topography of any other surface may be computed by reference to this, and hence absolute gradient currents are obtained. Where no isobaric surface is known to be level, the total gradient current will consist of the relative gradient current, due to the distribution of density, and the slope current, due to that portion of the inclination of the isobaric surfaces that is not the result of the distribution of density. See also geostrophic current.
Industry:Weather
In its restricted physical sense, any physical quantity that varies in three-dimensional space (and possibly time), usually continuously except possibly on surfaces or curves. Field quantities often satisfy partial differential equations. An example of a scalar field is the temperature T(x, y, z, t) at time t at each point (x, y, z) of a solid body; an example of a vector field is the (local) velocity field v(x, y, z, t) in a fluid, the separate parts of which are in motion relative to each other. The continuity of these fields is a mathematical fiction, obtained by averaging over volumes containing many atoms or molecules but still small on a macroscopic scale.
Industry:Weather
In Great Britain, the 12-month period starting 6 November. Compare farmer's year.
Industry:Weather
In Great Britain, the 12-month period starting with the Sunday nearest 1 March. Compare grower's year.
Industry:Weather
In Italy, a southwest wind, vehement and short-lived, followed by a gale from the south or southeast, which blows in the vicinity of the Po River.
Industry:Weather
In global atmospheric models using the spectral method, the physical grid required for alias-free evaluation of the quadratic terms in the equations of motion (e.g., horizontal advection). The resolution of the grid is determined by the spectral truncation and the requirements for the transformations of the spherical harmonics (Fourier transformation in longitude and Gaussian quadrature of the Legendre polynomials in latitude).
Industry:Weather
In general, cycles of freezing and thawing of water contained in natural or man-made materials. This is especially applied to the disruptive effects of this action. In geology, two basic types of frost action are described: 1) congelifraction, the shattering or splitting of rock material; and 2) congeliturbation, the churning, heaving, and thrusting of soil material.
Industry:Weather
In fuzzy logic, a quantity that can take on linguistic rather than precise numerical values. For example, a fuzzy variable, temperature, might have values such as “high,” “medium,” and “low. ”
Industry:Weather
