- 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, ...
1. Pertaining to temperature or heat. 2. A discrete buoyant element in which the buoyancy is confined to a limited volume of fluid. See plume. 3. A relatively small-scale, rising current of air produced when the atmosphere is heated enough locally by the earth's surface to produce absolute instability in its lowest layers. The use of this term is usually reserved to denote those currents either too small and/or too dry to produce convective clouds; thus, thermals are a common source of low-level clear-air turbulence. It is generally believed that the term originated in glider flying, and it is still very commonly used in this reference.
Industry:Weather
1. In general, any tornado over a body of water. 2. In its most common form, a nonsupercell tornado over water. Such events consist of an intense columnar vortex (usually containing a funnel cloud) that occurs over a body of water and is connected to a cumuliform cloud. Waterspouts exhibit a five- stage, discrete life cycle observable from aircraft: 1) dark-spot stage; 2) spiral pattern stage; 3) spray-ring stage; 4) mature or spray-vortex stage; and 5) decay stage. Waterspouts occur most frequently in the subtropics during the warm season; more are reported in the lower Florida Keys than in any other place in the world. Funnel diameters range from a few up to 100 m or more; lifetimes average 5–10 minutes, but large waterspouts can persist for up to one hour.
Industry:Weather
1. Isobaric wet-bulb temperature: the temperature an air parcel would have if cooled adiabatically to saturation at constant pressure by evaporation of water into it, all latent heat being supplied by the parcel. 2. Adiabatic wet-bulb temperature (or pseudo wet-bulb temperature): the temperature an air parcel would have if cooled adiabatically to saturation and then compressed adiabatically to the original pressure in a moist-adiabatic process. This is the wet-bulb temperature as read off the thermodynamic diagram and is always less than the isobaric wet-bulb temperature, usually by a fraction of a degree centigrade. 3. The temperature read from the wet-bulb thermometer.
Industry:Weather
1. Irregular fluctuations occurring in fluid motions. It is characteristic of turbulence that the fluctuations occur in all three velocity components and are unpredictable in detail; however, statistically distinct properties of the turbulence can be identified and profitably analyzed. Turbulence exhibits a broad range of spatial and temporal scales resulting in efficient mixing of fluid properties. Analysis reveals that the kinetic energy of turbulence flows from the larger spatial scales to smaller and smaller scales and ultimately is transformed by molecular (viscous) dissipation to thermal energy. Therefore, to maintain turbulence, kinetic energy must be supplied at the larger scales. See Also ocean mixing. 2. Random and continuously changing air motions that are superposed on the mean motion of the air. See aircraft turbulence.
Industry:Weather
1. In the equation for the time constant of a thermometer, a quantity equal to the product of wind speed and air density. The time constant varies inversely with ventilation. The concentration of an air pollutant is inversely proportional to the ventilation, the mass flux of “clean air” moving past the observer. Stagnation, a condition caused by the lack of ventilation, is historically associated with major air pollution episodes. It occurs due to the lack of horizontal wind speed and the lack of vertical wind speed, for example, caused by an inversion. 2. The exchange of properties with the surface layer such that property concentrations are brought closer to equilibrium values with the atmosphere. Such exchange may occur without water mass formation. 3. In weather-observing terminology, the process of causing “representative” air to be in contact with the sensing elements of observing instruments; especially applied to producing a flow of air past the bulb of a wet-bulb thermometer.
Industry:Weather
1. In storm-warning terminology, a wind of 48 to 63 knots (55 to 72 mph). 2. In the Beaufort wind scale, a wind with a speed from 48 to 55 knots (55 to 63 mph) or Beaufort Number 10 (Force 10).
Industry:Weather
1. In general, an unmeasurable (less than 0. 01 in. ) quantity of precipitation. 2. An insignificantly small quantity. 3. The record made by any self-registering instrument. Thus, one may speak of the barograph trace, the hygrothermograph trace, etc.
Industry:Weather
1. In expert systems, the determination of how well the task is performed. For weather forecast expert systems, it corresponds to forecast verification. Consequently, there is often confusion among meteorologists between validation and verification as used in artificial intelligence. 2. Comparison of a measurement from a new instrument or technique with older, established measurements of the same property or parameter.
Industry:Weather
1. Generally, the disposition of the major natural and man-made physical features of the earth's surface, such as would be entered on a map. This may include forests, rivers, highways, bridges, etc. , as well as contour lines of elevation, although the term is often used to denote elevation characteristics (particularly orographic features) alone. 2. The study or process of topographic mapping.
Industry:Weather
1. Generally, any pattern with some roughly identifiable periodicity in time and/or space. This applies, in meteorology, to atmospheric waves in the horizontal flow pattern (e.g., Rossby wave, long wave, short wave, cyclone wave, barotropic disturbance). See Also inertia wave. 2. At the surface of the ocean, a disturbance generated by wind action with dynamics governed by the influence of gravity and/or surface tension. See ocean waves. 3. Popularly used as a synonym for “surge” or “influx,” as in tidal wave (storm surge), heat wave, cold wave.
Industry:Weather
