- 업종: 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, ...
The condition that the pressure must be continuous across an internal boundary or free surface in a fluid. This condition is applied in meteorology, for example, at frontal surfaces and at the tropopause. See also boundary conditions.
Industry:Weather
Laser in which the radiation from a fixed-wavelength laser is focused into an organic dye, which then emits at a longer wavelength. The resulting radiation, usually in the visible range, is tunable, so a much wider range of molecules can be detected. The lasers can be either pulsed or continuous. Uses include lidar, sensing of atmospheric trace gases, particularly free radicals, and the detection of atmospheric gases in laboratory kinetics experiments.
Industry:Weather
An analysis procedure, named after Vern Dvorak, for determining hurricane intensity from cloud patterns in satellite images.
Industry:Weather
The total volume of irrigation water required for a particular type of crop to mature. It includes consumptive use, evaporation and seepage from ditches and canals, and the water eventually returned to streams by percolation and surface runoff.
Industry:Weather
An unusual, frequently severe weather condition characterized by strong winds and dust-filled air over an extensive area. Prerequisite to a duststorm is a period of drought over an area of normally arable land, thus providing the very fine particles of dust that distinguish it from the more common sandstorm of desert regions. A duststorm usually arises suddenly in the form of an advancing dust wall that may be many kilometers long and and a kilometer or so deep, ahead of which there may be some dust whirls, either detached or merging with the main mass. Ahead of the dust wall the air is very hot and the wind is light. In U. S. Weather observing practice, if blowing dust reduces visibility to between 5/8 and 5/16 statute mile, a “duststorm” is reported; if the visibility is reduced to below 5/16 statute mile, it is reported as a “severe duststorm. ” Duststorm winds can also be associated with thunderstorm outflows and gust fronts. While these are often shorter-lived than synoptically forced duststorms, they can be quite intense, with an impressive leading edge of the dusty gust front, sometimes called a dust wall. Compare haboob.
Industry:Weather
Devices for the removal of relatively large particles from ambient air by means of gravitational sedimentation.
Industry:Weather
In atmospheric electricity, a rather sudden and short-lived change of the vertical component of the atmospheric electric field that accompanies the passage of a dust devil near an instrument sensitive to the vertical gradient. Such changes may be either positive or negative and the charge is probably produced by triboelectrification.
Industry:Weather
A rapidly rotating column of air (whirlwind) over a dry and dusty or shady area, carrying dust, leaves, and other light material picked up from the ground. When well developed it is known as a dust devil. Dust whirls typically form as the result of strong convection during sunny, hot, calm summer afternoons. This type is generally several meters in diameter at the base, narrowing for a short distance upward and then expanding again, like two cones apex to apex. Their height varies; normally it is only 30–100 m, but in hot desert country it may be as high as 1 km. Rotation may be either clockwise or counterclockwise. Dust whirls move erratically, from one patch of heated air to another, and generally slowly. In desert country it is not unusual for three or more desert devils to be visible at the same time. Another type of vigorous dust whirl occurs under the bases of cumulonimbus or cumulus clouds, almost always on or near a wind-shift line. These vortices often inflict little or no damage and are short- lived, but occasionally represent the first visible sign of a developing tornado. Another form of dust whirl, often seen at street corners, is merely an eddy caused by the meeting of winds blowing along two intersecting streets. Such whirls are small and very short-lived. Compare duststorm.
Industry:Weather
A pit in an ice surface produced by small, dark particles on the ice. This phenomenon occurs primarily during sunny conditions when the dust absorbs more solar shortwave radiation than the regional ice causing the dust to melt down into the ice. Compare cryoconite hole.
Industry:Weather
