- المجال: 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 angle between the direction of propagation of an electromagnetic or acoustic wave (or ray) incident on a body and the local normal to that body (although this normal may not be well defined, as that for a cloud, e.g.). May also describe beams of particles in the broadest sense. Compare angle of arrival.
Industry:Weather
A land and sea breeze system of Malaya. The land breeze is called angin-darat; the sea breeze, angin-laut.
Industry:Weather
The angle between the propagation direction of an incident wave and some reference direction, which in radio engineering may be fixed relative to a receiver (e.g., the normal to a horizontal plane).
Industry:Weather
A radar echo caused by a physical phenomenon not discernible by eye at the radar site. Angels may appear as coherent or incoherent echoes. When diffuse and incoherent appearing, they are sometimes called ghost echoes. Angel echoes observed by radars with wavelengths of about 10 cm and less are usually caused by birds or insects. Radars with longer wavelengths and radar wind profilers, which operate in the UHF and VHF radio frequency bands, regularly detect echoes from the optically clear air that are caused by spatial fluctuations of the atmospheric refractive index. See Bragg scattering; compare clear-air echo.
Industry:Weather
An instrument for measuring atmospheric pressure. It is constructed on the following principles: An aneroid capsule (a thin corrugated hollow disk) is partially evacuated of gas and is restrained from collapsing by an external or internal spring; the deflection of the spring will be nearly proportional to the difference between the internal and external pressures; magnification of the spring deflection is obtained both by connecting capsules in series and by mechanical linkages. The aneroid barometer is temperature compensated at a given pressure level by adjustment of the residual gas in the aneroid or by a bimetallic link arrangement. The instrument is subject to uncertainties due to variations in the elastic properties of the spring and capsules, and due to wear in the mechanical linkages. See barometer, aneroid barograph, pressure altimeter, altimeter-setting indicator.
Industry:Weather
An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen that graphs a record on a rotating drum. The magnification of the deflection of the capsule may be adjusted so that records of small fluctuations in pressure may be obtained. The aneroid barograph is subject to the uncertainties of the aneroid barometer and therefore must be calibrated periodically. See also barograph, microbarograph.
Industry:Weather
One of two general classes of radar indicator in which the sweep of the electron beam is deflected vertically or horizontally from a base line to indicate the existence of an echo from a target. The amount of deflection is usually a function of the echo signal strength. Common types of amplitude-modulated indicators give only the slant range between radar and target. However, since the characteristics of the target signal can be easily observed with this type of indicator, it is very useful in radar meteorology.
Industry:Weather
1. Literally, “not wet,” containing no liquid; applied to a kind of barometer that contains no liquid, an aneroid barometer. 2. Same as aneroid barometer.
Industry:Weather
The general name for instruments designed to measure either total wind speed or the speed of one or more linear components of the wind vector. These instruments may be classified according to the transducer employed; those commonly used in meteorology include the cup, propeller, Pitot-tube, hot-wire or hot-film, and sonic anemometers. See also current meter, wind vane.
Industry:Weather
1. The height above the surface at which an anemometer is actually exposed. 2. The ideal exposure height of an anemometer; usually designed to be above the wakes that form behind individual surface roughness elements such as nearby trees, houses, or ship structures. 3. The desired or standard exposure height of an anemometer, as specified by national or international agreement. This height is usually taken as 10 m.
Industry:Weather
