- 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 visible or audible manifestation of atmospheric electricity. This includes, therefore, not only igneous meteors, but also the sounds produced by them, principally thunder.
Industry:Weather
Energy propagated in the form of an advancing electric and magnetic field disturbance. The term radiation, alone, is commonly used for this type of energy, although it actually has a broader meaning. In the classical wave theory of light (or electromagnetic theory) the propagation is thought of as a continuous wavelike disturbance of the electric and magnetic fields, which oscillate in planes orthogonal to each other and to the direction of propagation. The quantum theory of electromagnetic radiation adds the perspective that these disturbances also have particle-like attributes, being quantized into photons of minimum energy that have finite momentum. The observable properties and physical effects of various portions of the electromagnetic spectrum are of considerable importance in meteorology and are discussed under their respective names. See cosmic rays, gamma rays, x-rays, ultraviolet radiation, visible radiation, infrared radiation, microwave radiation, radio waves.
Industry:Weather
A field entity comprising the electric field E and the magnetic field (or magnetic induction) B. All electric and magnetic fields are electromagnetic fields because the decomposition of these fields is not unique. This is evident from the Lorentz force (see magnetic induction) on a charge, which depends on its velocity in a given inertial coordinate system. In another inertial coordinate system velocity, and hence the Lorentz force, is different. But ultimately it is only by means of the Lorentz force that fields are observed. Thus, two observers moving with a constant velocity relative to each other will not agree on whether a particular field is solely electric or solely magnetic.
Industry:Weather
The energy of electromagnetic radiation. This may be thought of in a quantum mechanical sense as the sum of all the photon energies composing the radiation, or in a classical sense as the combined energy contained in the oscillating electric and magnetic fields.
Industry:Weather
Strong concentrated electric currents flowing in the lower ionosphere. The equatorial electrojet flows along the earth's magnetic dip equator and is present at all times, while the auroral electrojet is a more sporadic phenomenon occurring in association with auroral displays at high magnetic latitudes.
Industry:Weather
A device tested in the late 1950s and 1960s that used acoustic waves to create clear-air targets for a continuous-wave radar. The acoustic source produces sound waves that perturb the atmospheric refractive index. The perturbations propagate at the local speed of sound and serve as targets for the radar. When the acoustic wavelength is matched to half the radar wavelength, a resonance condition develops that leads to the production of a detectable radar echo (see Bragg scattering). The Doppler shift of this radar echo is a function of the virtual temperature and the wind component along the direction of the radar beam. Radio acoustic sounding systems (RASS) also use this principle, but with a vertically pointed beam so that the Doppler shift depends on virtual temperature and the vertical wind component. The vertical wind component in RASS is removed either by time averaging or by making independent measurements of the wind. The EMAC probe was designed to make wind measurements with an operating range of 400 m. The virtual temperature (and corresponding speed of sound) was assumed, based on an independent measurement at the radar site.
Industry:Weather
The accumulation of an excess of ions of positive sign in the neighborhood of a negative electrode, and vice versa, when ions are continuously produced in the space above the electrode and move under the influence of the electrode's field.
Industry:Weather
A thermometer that uses a transducing element with electrical properties that are a function of its thermal state. Common meteorological examples of such thermometers are the resistance thermometer and the thermoelectric or thermocouple thermometer.
Industry:Weather
A radiometer for which the output of the thermal detector is measured as the detector is alternately exposed to a radiant energy source and then to a known internal electrical heating. Radiant heating per unit area of an entrance aperture is then equated to the electrical energy used to equivalently heat the detector.
Industry:Weather
1. Popular term for thunderstorm. 2. Sometimes applied to a relatively rare condition of disturbed atmospheric electric field in the lower atmosphere that arises when strong winds are blowing and much dust is in the air, but there is no thunderstorm activity. Triboelectrification due to the blowing dust may charge fences and other metallic objects to such an extent that slight shocks are felt upon touch. 3. Same as earth-current storm.
Industry:Weather
