- 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 difficulty in turbulence theory caused by more unknowns than equations. The closure problem of turbulence is alternately described as the requirement for an infinite number of equations, which would also be impossible to solve. This problem is apparently associated with the nonlinear nature of turbulence, and the traditional analytical approach of Reynolds averaging the governing equations to eliminate linear terms while retaining the nonlinear terms as statistical correlations of various orders (i.e., consisting of the product of multiple dependent variables). The closure problem is a long-standing unsolved problem of classical (Newtonian) physics. While no exact solution has been found to date, approximations called closure assumptions can be made to allow approximate solution of the equations for practical applications.
Industry:Weather
A flow in parallel planes in which streamlines and other isopleths are concentric circles about a common axis. One atmospheric model of easterly and westerly winds is a circular vortex about the earth's polar axis. The stability properties of this model have been extensively investigated.
Industry:Weather
A flow (15 knots or more) of cold air across an isotherm ribbon. Compare polar outbreak.
Industry:Weather
A finite-difference approximation with the property that the numerical solution tends to the exact solution of the differential equation as the grid length becomes small. See Lax equivalence theorem, consistent numerical scheme, stability.
Industry:Weather
A finite-difference approximation that approaches the corresponding differential equation as the grid length becomes small. See Lax equivalence theorem, convergent numerical scheme, stability.
Industry:Weather
A disturbance along a cold front, often accompanied by clouds, precipitation, and a low pressure center. See frontal wave.
Industry:Weather
A display or mapping of the maximum radar reflectivity factor at any altitude as a function of position on the ground.
Industry:Weather
A diagram that indicates, for a given ocean area, the average percentage of current setting toward each of the principal compass points. The distribution of drifts is sometimes also indicated. Compare wind rose.
Industry:Weather
A device that measures the number concentration of particles upon which a vapor (typically water vapor) condenses at high values of supersaturation, relative to equilibrium vapor pressure over the liquid phase of the substance. The value of supersaturation in these devices may be higher than that encountered in a cloud condensation nuclei counter, in which the supersaturation of water vapor is controlled to values that are typically found in liquid water clouds.
Industry:Weather
A device used to record the highest water stage since the last gauge reading.
Industry:Weather
