- 行业: Weather
- Number of terms: 60695
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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, ...
The equilibrium angle of contact of a liquid on a rigid surface, measured within the liquid at the contact line where three phases (liquid, solid, gas) meet. For example, water sheeting on glass has zero contact angle, but water beading on an oily surface or plastic may have a contact angle of 90° or greater.
Industry:Weather
Like cumulus; generally descriptive of all clouds, the principal characteristic of which is vertical development in the form of rising mounds, domes, or towers. This is the contrasting form to the horizontally extended stratiform types. Cumulus are driven by thermal convection and typically have vertical velocities in excess of 1 meter per second.
Industry:Weather
The fraction of direct solar radiation that arrives at the earth's surface when the sun is at the zenith. The coefficient appears in the mathematical expression of Bouguer's law (Beer's law, Lambert's law).
Industry:Weather
The fraction of all collisions between water drops of a specified size that results in actual merging of the two drops into a single larger drop. In discussing the details of the growth of raindrops by collision and coalescence, it is important to distinguish clearly the terms coalescence efficiency, collision efficiency, and collection efficiency, the last being equal to the product of the first two.
Industry:Weather
Linear cloud organization occurring atop the updraft branches of horizontal convective rolls when sufficient moisture is present. Cloud streets are readily observed with satellite imagery and can extend for hundreds of kilometers, particularly where the underlying surface is uniform.
Industry:Weather
The formation of depressions by convective ascent of heated surface air during a sufficient interval and of sufficient magnitude for the inflowing air near the earth's surface to acquire appreciable cyclonic rotation in accordance with the circulation theorem. Compare wave theory of cyclones.
Industry:Weather
The formation of a second pressure center within a well-developed pressure system, nearly always a low. The original low pressure center usually diminishes in magnitude as the new center deepens. The center of the cyclone appears to jump from the first to the second point of low pressure and can occur at a point farther along the original path of the low or may form along a new path displaced from the original low.
Industry:Weather
The formation of ice in the throat of a carburetor as the result of cooling by expansion and evaporation of gasoline. At one time a serious problem in aviation, carburetor heaters now render this unimportant. Carburetor icing often occurs at ambient air temperatures as high as 50°–60°F, the necessary cooling to the frost point occurring within the carburetor throat. Compare aircraft icing.
Industry:Weather
The flow condition of a fluid system when one of the fundamental nondimensional parameters has a critical value, for example, flow of water in an open channel at a Froude number of 1, flow of gas at a Mach number of 1, flow in a pipe at Reynolds number greater than 2100, or shear flow in the atmosphere at Richardson number less than 0. 25. As each parameter crosses its critical value, the nature of the flow changes, such as from straight to wavy, from laminar to turbulent, or from linear to nonlinear.
Industry:Weather