- 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 probe used to measure the electron temperature of ionized plasmas. Langmuir probes mounted on spacecraft are often used to measure the electron temperature of the earth's ionosphere.
Industry:Weather
A power amplifier tube used to amplify weak microwave energy (provided by a radio- frequency exciter) to a high power level for a radar transmitter. A klystron is characterized by high power, large size, high stability, high gain, and high operating voltages. Electrons are formed into a beam that is velocity modulated by the input waveform to produce microwave energy. A klystron is sometimes referred to as a linear beam tube because the direction of the electric field that accelerates the electron beam coincides with the axis of the magnetic field, in contrast to a crossed-field tube such as a magnetron. Klystrons provide a coherent transmitted signal appropriate for Doppler radar and pulse-compression applications. They are used in many operational radars, for example, NEXRAD (Next Generation Weather Radar) and TDWR (Terminal Doppler Weather Radar). Compare magnetron.
Industry:Weather
A numerical model with an averaging volume sufficiently small that the eddies contained entirely within it (i.e., the unresolved eddies) are of inertial-range scales and smaller. The larger energy-containing eddies are resolved explicitly away from the boundaries. In the boundary layer the energy-containing eddies are not resolved near the surface and near the inversion at the top. In these regions a subgrid-scale parameterization is needed.
Industry:Weather
A pollutant concentration level (specific to the averaging time being considered) associated with a condition of exposure, often for sensitive population groups. Concentrations above the level of concern are related to undesirable health effects, while concentrations below this level do not cause perceptible health effects of significant duration.
Industry:Weather
A photometric unit of illuminance or illumination equal to one lumen per square meter. A level of illumination between 200 and 1000 lux is generally considered to be adequate for homes and offices. Compare foot-candle.
Industry:Weather
A persistent east wind in the Adriatic, usually bringing cloudy weather. Compare levante, greco, gregale.
Industry:Weather
A period between approximately A. D. 1550 (or perhaps as early as 1300) and 1850 in which mountain glaciers advanced in many parts of the world. The precise timing of the advances and retreats varied from region to region. Temperatures were not uniformly colder throughout this period, but rather showed marked variations on decadal timescales.
Industry:Weather
A method of approximating the effects of turbulence at some height zk that considers only the meteorological state in the immediate vicinity of that height. For example, if estimating a turbulent flux at zk, one need consider only the meteorological state (wind speed, wind shear, wind curvature, temperature gradient, etc. ) at zk. The same approach works for higher-order turbulence statistics at zk, which can be estimated from values and gradients of lower-order statistics. Local closure implicitly assumes that turbulence consists of only small eddies, and thus it has difficulty approximating those flows where large eddies are important, such as for thermals in the convective boundary layer. Nonetheless, local closures are easier to use than nonlocal closures.
Industry:Weather
A numerical model with a horizontal domain that does not cover the entire globe. Such models must be given lateral boundary conditions from either a global forecast model or from another limited-area forecast model with a domain that completely encompasses the original one.
Industry:Weather
A nonuniform scale representing the function y = log x. See logarithm, alignment chart.
Industry:Weather
