- 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, ...
In meteorology, the general geometric characteristics of the distribution of height of a constant-pressure surface as shown by contour lines on a constant-pressure chart. Compare pressure pattern, circulation pattern.
Industry:Weather
A line connecting points on the earth's surface at which the aurora is observed with equal frequency.
Industry:Weather
A radio device for determining the distribution of virtual height with frequency, and the critical frequencies of the various “layers” of the ionosphere. A pulse at a certain frequency is transmitted vertically, and the time for its return is recorded on an oscilloscope; another pulse at a different frequency is then transmitted and timed. The process is repeated until the entire frequency range of interest, usually from about 1 to 25 MHz, has been explored.
Industry:Weather
A surface separating two fluids, across which there is a discontinuity of some fluid property, such as density, velocity, etc. , or of some derivative of one of these properties in a direction normal to the interface. Therefore, the equations of motion do not apply at the interface but are replaced by the kinematic and dynamic boundary conditions. See surface of discontinuity.
Industry:Weather
A surface separating two fluids, across which there is a discontinuity of some fluid property, such as density, velocity, etc. , or of some derivative of one of these properties in a direction normal to the interface. Therefore, the equations of motion do not apply at the interface but are replaced by the kinematic and dynamic boundary conditions. See surface of discontinuity.
Industry:Weather
The range of length scales over which energy is transferred and dissipation due to molecular viscosity is negligible. The power spectrum has power law behavior over the inertial range. In two-dimensional turbulence the power spectrum is theoretically proportional to k−3 in which k is the wavenumber, and in three-dimensional turbulence the power spectrum is theoretically proportional to k−5/3. The latter is known as the Kolmogorov minus 5/3 law.
Industry:Weather
A nonviscous fluid, that is, a fluid for which all surface forces exerted on the boundaries of each small element of the fluid act normal to these boundaries. By definition, therefore, the stress tensor reduces to the pressure, a point-function scalar in the fluid. Thus, in the dynamics of an inviscid fluid, as opposed to a real viscous fluid, 1) no restraints are placed on the tangential component of the flow at a solid bounding surface, and 2) there is no dissipation of kinetic into thermal energy within the fluid. In the free atmosphere the flow is often treated as inviscid, and the viscous forces may be neglected for many purposes. Where an inviscid fluid flows along a surface, that surface is said to be a free slip surface.
Industry:Weather
In aviation terminology, route or terminal weather conditions of sufficiently low visibility to require the operation of aircraft under instrument flight rules.
Industry:Weather
