- 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 production of ions in the atmosphere by the loss of an electron from a molecule, typically, for example, by cosmic rays or cosmic radiation. Radioactivity at the surface can also produce ions in the lowest layer of the atmosphere. See ionization.
Industry:Weather
1. Electrical phenomena, regarded collectively, that occur in the earth's atmosphere. These phenomena include not only such striking manifestations as lightning and St. Elmo's fire, but also less noticeable but more ubiquitous effects such as atmospheric ionization, the air– earth current, and other quiescent electrical processes. The existence of separated electric charges in the atmosphere is a consequence of many minor processes (spray electrification, dust electrification, etc. ) and a few major processes (cosmic-ray ionization, radioactive-particle ionization, and thunderstorm electrification). The details of thunderstorm charge separation are poorly understood. The maintenance of the prevailing atmospheric electric field is now widely believed to be due to thunderstorm effects. 2. The study of electrical processes occurring within the atmosphere.
Industry:Weather
A quantitative term denoting the electric field strength of the atmosphere at any specified point in space and time. In areas of fair weather, the atmospheric electric field near the earth's surface typically is about 100 volts (V) m−1 and is directed vertically in such a sense as to drive positive charges downward to the earth. In areas of fair weather this field decreases in magnitude with increasing altitude, falling, for example, to only about 5 V m−1 at an altitude of about 10 km. Near thunderstorms, and under clouds of vertical development, the surface electric field (the electric field measured at the surface of the earth) varies widely in magnitude and direction, usually reversing its direction immediately beneath active thunderstorms. In areas of minimal local disturbance, a characteristic diurnal variation of electric field strength is observed. This variation is characterized by a maximum that occurs at about 1900 UTC for all points on the earth and is now believed to be produced by thunderstorms that, for geographic regions, are more numerous for the world as a whole at that universal time than at any other. It is now believed that thunderstorms, by replenishing the negative charge to the earth's surface, provide the supply current to maintain the fair- weather electric field in spite of the continued flow of the air–earth current that tends to neutralize that field. The range of the electric field in fair weather varies considerably with geographical area, from one part of the globe to another. If, however, there are no local sources of pollution, the surface electric field has its maximum amplitude around 1900 UTC.
Industry:Weather
The study of those motions of the atmosphere that are associated with weather and climate. In atmospheric dynamics the fluid is regarded as a continuous medium, and the fundamental laws of fluid mechanics and thermodynamics are expressed in terms of partial differential equations involving the fluid velocity, density, pressure, and temperature.
Industry:Weather
1. Any interruption of a state of equilibrium of the atmosphere. 2. An area showing signs of a developing cyclonic circulation.
Industry:Weather
The evapotranspiration that would be achieved from a well-aerated soil/ plant surface at field water-holding capacity. Water loss may differ from pan evaporation according to the index of evaporating surface to horizontal area, roughness, and other physical and biological attributes of a site.
Industry:Weather
Correction made to remotely sensed radiance to account for effects related to the intervening atmosphere between the earth's surface and the satellite.
Industry:Weather
A mathematical model for quantitatively describing, simulating, and analyzing the structure of the circulation in the atmosphere and the underlying causes.
Industry:Weather
The study of the composition of and chemical transformations occurring in the atmosphere. The discipline of atmospheric chemistry includes field measurements, computer modeling, and laboratory measurements, and requires an understanding of the interaction of the atmosphere with the biosphere and anthropogenic influences in order to be able to explain current conditions and to predict future changes.
Industry:Weather
