- 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, ...
A mechanical anemometer with a vertical axis of rotation, usually consisting of three or four hemispherical or conical cups mounted with their diametrical planes vertical and distributed symmetrically about the axis of rotation. The rate of rotation of the cups is a measure of the wind speed. In gusty wind, the cup anemometer overestimates the mean wind speed.
Industry:Weather
A mercury barometer in which the lower mercury surface is larger in area than the upper surface. The basic construction of a cistern barometer is as follows: A glass tube 1 m in length, sealed at one end, is filled with mercury, and then inverted. The tube is mounted so that its mouth penetrates the upper surface of a reservoir of mercury called the cistern of the barometer. Cistern barometers are classified according to whether the cistern is fixed in volume (see Kew barometer) or variable in volume (see Fortin barometer).
Industry:Weather
A medium-sized instrument shelter used extensively at second-order stations, climatological substations, etc. It is a white louvered box with a flat double roof and is mounted slightly more than a meter (4 ft) above the ground on a four-legged stand.
Industry:Weather
A measure of the specific rate of disappearance of small ions due to either 1) union with neutral Aitken nuclei to form new large ions; or 2) union with large ions of opposite sign to form neutral Aitken nuclei. Dimensionally, a combination coefficient is identical with the physically similar recombination coefficient. Both types of combination coefficients exhibit mean values of the order of 10−5cm3s−1 at sea level, while the recombination coefficients are typically about one order of magnitude smaller. See recombination, small-ion combination.
Industry:Weather
A measure of the magnitude of one of several aspects of large-scale atmospheric circulation patterns. Indices most frequently measured represent the strength of the zonal (east–west) or meridional (north–south) components of the wind, at the surface or at the upper levels, usually averaged spatially and often averaged in time. See meridional index, zonal index.
Industry:Weather
A mean solar day reckoned from midnight to midnight, usually divided into two 12- hour divisions, although now often regarded as a single 24-hour series. As practically applied by use of meridional time zones of approximately 15° width, civil time is accurate (relative to mean solar time) to within ±30 minutes, or 7 ° of longitude. Minor exceptions occur when the time zones have been established according to geopolitical considerations, rather than adhering strictly to the meridians. See apparent solar day, day.
Industry:Weather
A measure of geomagnetic activity; use discontinued in 1975 and superseded by other indices of geomagnetic activity. See Kp.
Industry:Weather
A measure of statistical relationship that takes into account all functional relationships between random variables and contrasts to the correlation coefficient, which measure only the linear relationship.
Industry:Weather
A map that shows the configuration of a surface by means of contour lines drawn at regular intervals of elevation (contour intervals) above a reference level. In meteorology, the contour analysis of a constant-pressure chart is a type of contour map.
Industry:Weather
A mathematical representation of atmospheric dynamics that attempts to simulate the atmospheric motions and conditions characteristic of tropical, extratropical, or polar cyclones.
Industry:Weather
