- 行业: Weather
- Number of terms: 60695
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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, ...
The visibility observed from an airport tower. According to current U. S. Weather observing practice, at civil stations the control-tower visibility becomes the official visibility for the station whenever the surface visibility becomes less than three miles.
Industry:Weather
The water diverted from the boundary sources of an aquifer by lowering the water table or piezometric surface at a particular point in the aquifer.
Industry:Weather
The vertical optical thickness between the top and bottom of a cloud. Cloud optical depths are relatively independent of wavelength throughout the visible spectrum, but rise rapidly in the infrared due to absorption by water, and many clouds approximate blackbodies in the thermal infrared. In the visible portion of the spectrum, the cloud optical depth is almost entirely due to scattering by droplets or crystals, and ranges through orders of magnitude from low values less than 0. 1 for thin cirrus to over 1000 for a large cumulonimbus. Cloud optical depths depend directly on the cloud thickness, the liquid or ice water content, and the size distribution of the water droplets or ice crystals.
Industry:Weather
The vegetative covering over a surface. The canopy is often considered to be the outer surfaces of the vegetation. Plant height and the distribution, orientation, and shape of plant leaves within a canopy influence the atmospheric environment and many plant processes within the canopy.
Industry:Weather
The value of the gradient Richardson number below which air becomes dynamically unstable and turbulent. This value is usually taken as Ric = 0. 25, although suggestions in the literature range from 0. 2 to 1. 0. There is also some suggestion of hysteresis, where laminar air flow must drop below Ri = 0. 25 to become turbulent, but turbulent flow can exist up to Ri = 1. 0 before becoming laminar.
Industry:Weather
The vaguely defined region of the upper atmosphere in which photochemical reactions take place. It is generally considered to include the stratosphere (or the top thereof) and the mesosphere, and sometimes the lower part of the thermosphere. This entire region is the seat of a number of important photochemical reactions involving atomic oxygen O, molecular oxygen O2, ozone O3, hydroxyl OH, nitrogen N2, sodium Na, and other constituents to a lesser degree. See atmospheric shell.
Industry:Weather
The unmodulated fundamental output of a radio or radar transmitter, which is capable of being modulated with information to produce a communications signal.
Industry:Weather
The use of electromechanical devices to reduce (compensate for) the sensitivities of meteorological sensors to other parameters (e.g., the effect of temperature on a pressure sensor).
Industry:Weather
The total amount of water taken up by vegetation for transpiration or building of plant tissue, plus the unavoidable evaporation of soil moisture, snow, and intercepted precipitation (interception) associated with the vegetal growth. Consumptive use is primarily applied to a single type of vegetation in a given area and does not include evaporation from water surfaces in or adjacent to the area; thus, it is not as general in scope as evapotranspiration or duty of water.
Industry:Weather
