- 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 dense “fog” caused when the bora lifts a spray of small drops from the surface of the sea. It is well developed on the coast of Norway when a bora-like fall wind descends from the Scandinavian mountains as a sudden storm from the east.
Industry:Weather
A condition that occurs at sufficiently high Reynolds numbers in which the surface streamlines break away from the surface. Separation is due to the presence of a solid boundary, at which the no-slip condition.
Industry:Weather
A combination cup anemometer and pressure-plate anemometer, consisting of an array of cups about a vertical axis of rotation, the free rotation of which is restricted by a suitable spring arrangement. By proper adjustment of the force constant of the spring, it is possible to obtain an angular displacement that is proportional to wind velocity. The instrument was developed in 1880. The early version used four cups arranged helically, while the more modern version used a wheel with 32 cups. A bridled-cup anemometer was frequently used to measure high wind speeds.
Industry:Weather
A colloquial term for a duststorm in the Dust Bowl of the south-central United States.
Industry:Weather
A cold front that leads a cold air mass toward the south and southwest along the Atlantic seaboard of the United States. This is one of the occurrences to which New Englanders give the name sea turn, for the cold wind following a backdoor cold front blows from the northeast quadrant.
Industry:Weather
A closed curved tube of elliptical cross section used in some thermometers and barometers. The Bourdon-tube thermometer consists of a Bourdon tube completely filled with liquid. The expansion of the liquid due to a temperature change causes an increase in the radius of curvature of the tube. The curvature may then be measured by the travel of the tip of the tube. The Bourdon- tube barometer consists of an evacuated Bourdon tube and operates in a similar manner. In both cases the curvature is a measure of the difference between the pressure inside the tube and that outside.
Industry:Weather
A camera used for the observation of lightning flashes. The early model of this camera consists of a fixed film plate and two lenses that revolve at the opposite ends of a diameter of a circle. The velocity and duration of a lightning stroke can be computed from a comparison of the two photographs and a knowledge of the rate of rotation of the lenses. A later model consists of a fixed lens and a rotating film drum. This construction allows greater ease of interpretation.
Industry:Weather
A brightening of the base of a cloud layer caused by the reflection of light by snow or ice. See snow blink, ice blink.
Industry:Weather
A bow-shaped line of convective cells that is often associated with swaths of damaging straight-line winds and small tornadoes. Key structural features include an intense rear-inflow jet impinging on the core of the bow, with book-end or line-end vortices on both sides of the rear-inflow jet, behind the ends of the bowed convective segment. Bow echoes have been observed with scales between 20 and 200 km, and often have lifetimes between 3 and 6 h. At early stages in their evolution, both cyclonic and anticyclonic book-end vortices tend to be of similar strength, but later in the evolution, the northern cyclonic vortex often dominates, giving the convective system a comma-shaped appearance.
Industry:Weather
A bora on the Dalmatian coast of Croatia and Bosnia, with clouds and precipitation, the strong pressure gradient across the coast resulting from a cyclone (low pressure) system to the west.
Industry:Weather
