- 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, ...
Branch of applied hydrology that deals with engineering applications such as planning, designing, operating, and maintaining water resources projects.
Industry:Weather
Any of the possible discrete energies of an atom, molecule, or nucleus. According to Newtonian mechanics, the energy of a body is a continuous variable, but according to the quantum theory, measured energies of bound states are discrete, some said to be allowed, others forbidden. We are not aware of this discreteness for macroscopic objects because of the extreme (relative) smallness of the separation between their energy levels. During transitions from one energy level to another, quanta of radiant energy are emitted or absorbed, their frequency depending on the difference between energy levels. Emissions of this type are responsible for the aurora borealis, for example.
Industry:Weather
A range of eddy sizes containing much of the energy in the turbulence spectrum. Approximately centered on integral length scales, these eddies are larger than those in the inertial subrange and smaller than the semipermanent eddies associated with the spectrum's formation. See turbulence length scales.
Industry:Weather
Any process in which a system interacts with its surroundings in such a way that the energy of the system increases (or decreases) while that of the surroundings decreases (or increases) by the same amount. See also energy conversion.
Industry:Weather
The line above a datum used for expressing the total energy of a flow.
Industry:Weather
The balance between the net warming or cooling of a volume and all possible sources and sinks of energy. The main sources and sinks of energy typically include the net fluxes of sensible heat, latent heat, and radiant energy. Conservation of energy requires that the energy received by a surface must equal that lost from the surface plus that stored. For water and land surfaces, the main source of energy is net radiation, which equals the sum of short and long waveband radiation downward minus radiation reflected or emitted upward. This energy is normally transferred into the soil (soil heat flux), into the air (sensible heat flux), or into latent heat flux (evapotranspiration or ET). Small amounts of the incoming energy can change the heat content of water or crops at the surface or are converted to other forms of energy (e.g., photosynthesis). Energy balance is often used to estimate evapotranspiration by 1) measuring net radiation, soil heat flux, and sensible heat flux; 2) entering those values into an energy balance equation; and 3) solving for the latent heat flux (ET). Under hot, dry, windy (advection) conditions, heat from the air in addition to net radiation is sometimes available at an underlying cool surface. Advection can potentially increase evaporation rates to higher than the energy available from net radiation alone. See also surface energy balance.
Industry:Weather
The transfer of energy from larger eddies to smaller eddies in the inertial subrange of the spectrum of turbulence kinetic energy.
Industry:Weather
A measurable physical quantity, with dimensions mass times velocity squared, that is conserved for an isolated system. Energy of motion is kinetic energy; energy of position is potential energy. See energy conversion, internal energy, enthalpy.
Industry:Weather
A technique used in boundary layer meteorology to describe a type of mixed- layer growth that is governed by the amount of turbulence kinetic energy that is available for conversion into potential energy during entrainment of warm free-atmosphere air downward into the mixed layer. Compare encroachment method.
Industry:Weather
A characteristic in the electric field signature at the ground near the end of a thunderstorm. The electric field changes from upward-directed (foul-weather polarity) to downward-directed (fair-weather polarity) and often retains the latter polarity for several tens of minutes before returning momentarily to foul-weather polarity. Positive ground flashes and spider lightning are occasionally observed during the period of reversed field polarity. The origin of the EOSO is only partly understood.
Industry:Weather
