- 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, ...
The electrical signal that is obtained from a received radio signal after detection or demodulation; a general term pertaining to the picture signals in a television system or to the information- carrying signals that are eventually presented on the cathode ray tubes of a radar.
Industry:Weather
The electronic superposition of geographic or other data on a radar display.
Industry:Weather
The elevation band on a mountain or orographic barrier that receives the greatest precipitation for a seasonal or annual average. Typically, precipitation increases with height upward from the base of mountains, but, if the peaks are high enough, eventually a level is reached where precipitation decreases with height (precipitation inversion). The decrease often occurs because the cooler air at higher altitudes holds less moisture, so less water vapor is available to condense and precipitate. The level where the increases with height become decreases marks the zone of maximum precipitation. According to Miller (1961), the altitude of the zone, often between 1 and 2 km, “varies slightly from place to place, is lower in tropic than temperate zones, in humid climates than in arid, in the cold season than the hot, in the wet season than in the dry. ” See Also orographic precipitation.
Industry:Weather
The equinox at which the sun crosses the celestial equator from the Southern Hemisphere to the Northern Hemisphere. The time of this occurrence is approximately 21 March.
Industry:Weather
The evolution from a laminar to a turbulent state, usually via a sequence of distinct bifurcations.
Industry:Weather
The exchange of momentum between an ocean surface wave and the near-surface current.
Industry:Weather
The existence of regions of net charge in a thunderstorm. During transient collisions of ice crystals with riming graupel pellets, charge is transferred. The separating particles then carry equal and opposite charges; the larger (often negative) particles fall while the smaller ones (often positively charged ice crystals) are carried up in the updraft to produce a vertical electric field that eventually produces lightning. The charge transfer process is not completely understood, but possible processes include charges on the surface layers of the particles, charges on dislocations in the ice lattice, temperature differences along surface features that may be broken off during collisions, and contact potential differences between the surfaces of the interacting particles. See breaking-drop theory, ion-capture theory.
Industry:Weather
The finite increment of time over which a change of the value of a meteorological element is measured in order to estimate its tendency. The most familiar example is the three-hour time interval over which local pressure differences are measured in determining pressure tendency.
Industry:Weather
The flight of a constant-level balloon, the trajectory of which is determined by ground tracking equipment. Thus, it is a form of upper-air, quasi-horizontal “sounding. ” The most usual observations are of successive positions of the balloon located by radio direction-finding or radio-navigation equipment, giving trajectory, wind speed, and wind direction. Instrumentation can also be added to the balloon to sense and transmit pressure, temperature, relative humidity, and other meteorological elements.
Industry:Weather
