- 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, ...
An instrument showing qualitatively whether the air is dry or damp, usually by the change in appearance or dimensions of some substance (see chemical hygrometer). Hygroscopes are frequently used as home weather predictors, for example, “weather houses” in which the appearance of the “old man” or the “old woman” is determined by the twisting and untwisting of a piece of catgut in response to changes of humidity.
Industry:Weather
An instrument for measuring the extinction coefficient in water. See photometer.
Industry:Weather
An injection of air from one area or level to another. The air is typically the opposite of the surrounding air, that is, a cold air invasion into an area of warm air.
Industry:Weather
An instability of an unbounded stratified parallel shear flow to the development of cusplike waves that propagate with phase speed along the flow direction significantly different from the speed of the inflection point of the shear. The propagating phase speed of Holmboe instability distinguishes it from Kelvin–Helmholtz instability. The instability occurs only in stratified fluid due to a resonant coupling between an internal gravity wave and a wavelike disturbance where the background shear varies vertically.
Industry:Weather
An individual ice crystal in a deposit of hoarfrost. Such crystals always grow by deposition.
Industry:Weather
An idealized condition in which compressibility vanishes. Most liquids are nearly incompressible. For shallow layers of the atmosphere with velocity fluctuations much less than the speed of sound, incompressibility is a good approximation and is often made for mathematical convenience. For a fluid with a density depending on temperature, incompressibility does not imply non-divergence. See anelastic approximation, Boussinesq approximation.
Industry:Weather
An ice crust that has been covered by new snow. When exposed at a glacier front or in crevasses, the ice layers viewed in cross section are termed ice bands.
Industry:Weather
An experimental source of blackbody radiation in the form of an isothermal cavity with a small opening. The walls of the cavity are partially reflective and are kept at constant temperature, maintaining radiative equilibrium within the cavity. A hohlraum is also a perfect absorber since it traps all radiation that enters the small aperture.
Industry:Weather
An emitter of constant radiance with angle. Isotropic radiators obey Lambert's law.
Industry:Weather
An electric humidity sensor element often used in radiosonde equipment that relies on changes in the resistance of a humidity-sensitive component. A carbon humidity element is used in the United States. It comprises a polystyrene slide or strip with two metal electrodes along the long edges sprayed with a mixture of carbon particles and a cellulose binder. The binder changes its volume with relative humidity in such a way that it separates the carbon particles from each other as the humidity increases, thus increasing the resistance between the electrodes. The relative humidity is calibrated as a function of resistance.
Industry:Weather
