- 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, ...
Refers to the presence of ozone at the earth's surface. The term is also used in reference to the episodic observation of near total ozone depletion that occurs in certain regions of the arctic marine boundary layer in springtime. This ozone depletion (not to be confused with the stratospheric polar ozone hole) likely occurs as the result of bromine- and chlorine-catalyzed chemistry. The sources of the halogens are not well understood, but it is likely that they emanate from sea salt. See photochemical air pollution.
Industry:Weather
Reflection in which there is a pronounced maximum in the backward direction.
Industry:Weather
Regression analysis to determine from a set of independent variables (predictors) those contributing most to the explained variance. See regression.
Industry:Weather
Relationship between water level and discharge at a certain location in a stream or river, also referred to as a rating curve or uniform flow rating curve, expressed as a single valued function. Dynamic stage-discharge relationships, which form loop rating curves, occur when the stage is not just a function of the discharge, but is also a function of the variable energy slope.
Industry:Weather
Rapid vertical oscillations of the column of a mercury barometer. The oscillations are caused by the variations of ambient pressure due to the occurrence of wind gusts. Aboard ship, they may also be caused by the vessel's motion.
Industry:Weather
Rapid fluctuations in the amplitude and phase of electromagnetic or acoustic waves that have propagated through a medium containing fluctuations in refractive index, such as the atmosphere. The most common example of optical scintillation is the “twinkling” of stars observed through the atmosphere. Scintillation arises as a result of random angular scattering produced by refractive index fluctuations. For electromagnetic wave propagation, these result from fluctuations in temperature and, especially at far infrared and radio frequencies, humidity. Scintillation in acoustic wave propagation arises from velocity and temperature fluctuations. Fluctuations in the amplitude of different frequency components in the spectrum of an object can give rise to apparent changes in its color (chromatic scintillation); an example is the random red and blue twinkling of bright stars near the horizon. Scintillation statistics have been used to study turbulence in regions ranging from the planetary boundary layer to the ionosphere, as well as interplanetary and interstellar space. Scintillation is important for astronomical imaging, optical and radio communications, laser and acoustical propagation, active and passive remote sensing, and the performance of the Global Positioning System.
Industry:Weather
Ragged low clouds, usually stratus fractus or cumulus fractus, that occur below the main cloud base. They are often found in the vicinity of rainshafts. Several mechanisms may explain their occurrence. They may represent rising air that has greater-than-average humidity due to the evaporation of rain or water on the ground. They may evaporate before reaching the main cloud due to mixing with the intervening dry air. Scud may also be attributed to the breakup of raindrops. The breakup fragments that are able to accumulate in regions of high humidity in rainshafts may be the source of some scud. See pannus.
Industry:Weather
Rain of yellowish color caused by foreign matter (e.g., pollen, yellow dust) picked up by raindrops during descent. A dust-filled subcloud layer is required to yield this effect, and the particles must contain sufficient sulfur dioxide to be yellow in color. Compare blood rain, mud rain.
Industry:Weather
