- 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, ...
A significant contributor to the atmospheric chlorine budget, this compound, formula CCl4, has been used in industrial applications as a solvent. Its production is now banned as a result of the Montreal Protocol on Substances that Deplete the Ozone Layer.
Industry:Weather
A signal received by a radar that has a polarization orthogonal to that of the transmitted signal. Two polarizations are orthogonal if 1) the ellipses defined by their electric field vectors have the same axial ratio, 2) the major axes of the ellipses are at right angles, and 3) the electric field vectors rotate in opposite directions.
Industry:Weather
A shallow (typically < 1 km deep) mesoscale frontal zone marked by a distinct cyclonic windshift in a region of enhanced thermal contrast (≈ 5°–10°C/10 km). These fronts typically develop in coastal waters or within 100–200 km of the coast during the cooler half of the year when the land is cold relative to the ocean. In the United States coastal fronts are most frequent in New England, the Middle Atlantic states, the Carolinas, and Texas. The typical coastal front is oriented quasi-parallel to the coast and may extend for several hundred kilometers. During the winter, the coastal front may mark the boundary between frozen and nonfrozen precipitation. Given that coastal front development usually precedes synoptic-scale cyclogenesis and marks an axis of enhanced thermal contrast and a maximum in cyclonic vorticity and convergence, the coastal front often serves as a boundary along which intensifying synoptic- scale cyclones move poleward. Surface coastal front development typically occurs beneath the forward side of advancing troughs following the passage of the ridge axis aloft. Coastal fronts most frequently form equatorward of cold anticyclones where a warmer onshore flow encounters a colder continental air stream. Damming of cold air on coastal orographic barriers such as the Appalachians often appears to play an important role in coastal front development. Coastal thermal contrasts are augmented by differential diabatic heating where the onshore flow has passed over oceanic thermal boundaries such as the Gulf Stream and the adjacent continental airstream has passed over snow-covered land. Coastal fronts may form independently of cold anticyclones and associated cold air damming. In situ coastal front developments can occur near mountain barriers where upslope flow results in differential airmass cooling and stabilization and where offshore troughs form due to differential heating across oceanic thermal boundaries. Coastal front dissipation typically occurs with the cessation of onshore flow following cyclone passage.
Industry:Weather
A severe thunderstorm with vivid lightning and violent squalls coming from the land on the west coast of Nicaragua and Costa Rica in Central America. Chubascos are especially frequent in May, with a secondary maximum in October. Soon after noon, dark, heavy clouds form over the mountains, becoming denser and lower. At about 4 p. M. The southwesterly sea breeze veers to east-northeast, and the storm breaks, usually continuing until about 8 p. M.
Industry:Weather
A severe rain squall in the Mariana Islands (western Pacific Ocean) during the northeast monsoon. They occur from November to April or May, especially from January through March.
Industry:Weather
A set of chemical reactions in which the catalytic species involved in the reaction are constantly regenerated, allowing the reaction sequence to occur repeatedly. For example, ozone destruction in the stratosphere occurs via a number of catalytic cycles involving nitrogen-, hydrogen-, and chlorine-containing free radicals.
Industry:Weather
A series of wave cyclones occurring in the interval between major outbreaks of polar air. The series travels along the polar front, usually eastward and poleward. Typically, the polar front drifts eastward and equatorward, so that each cyclone of the family has its origin and trajectory at a lower latitude than the previous cyclone.
Industry:Weather
A semi-enclosed basin characterized by an excess of evaporation over precipitation plus runoff in which relatively fresh water enters through the strait in the surface layer, is made more saline by the net evaporation, and exits through the strait in a subsurface layer. The transformed saline water is more dense than the inflowing surface water and therefore sinks. The classic example of a concentration basin is the Mediterranean Sea.
Industry:Weather
A sequence of events by which a warm high or cold low, originally within the westerlies, becomes displaced either poleward (cut-off high) or equatorward (cut-off low) out of the westerly current. This process is evident at very high levels in the atmosphere; it frequently produces, or is part of the production of, a blocking situation.
Industry:Weather
A sea state of wind-generated ocean waves that consists of nonparallel wave systems. A cross sea has a large amount of directional spreading.
Industry:Weather
