- 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, ...
In weather-observing terminology, low-lying fog that does not obstruct horizontal visibility at a level 2 m (6 ft) or more above the surface of the earth. This is, almost invariably, a form of radiation fog. Compare ground fog.
Industry:Weather
In the early days of aviation, commonly used to describe weather at an airport when ceiling and/or visibility were of such low values that the airport was effectively closed to aircraft operations. The term probably originated from reference to the wind sock. When the sock was in the clouds or when the visibility was so badly impaired that the sock was not visible, the airport was “socked in. ” The expression is still widely used.
Industry:Weather
In W. Köppen's 1936 climatic classification, any climate type other than the dry climates. However, it is generally understood that this refers principally to the tree climates and not the polar climates. Compare moist climate, wet climate.
Industry:Weather
In U. S. Weather observing practice, the greatest horizontal visibility that is equaled or surpassed throughout half of the horizon circle; it need not be a continuous half. In the case of rapidly varying conditions, it is the average of the prevailing visibility while the observation is being taken. This value is entered in a surface weather observation. If the value is less than seven miles, it must be explained by reporting a type of weather or obstruction to vision.
Industry:Weather
In tropical meteorology, a wave trough in the circumpolar westerlies having sufficient amplitude to reach the Tropics in the upper air. At the surface it is manifest as a trough in the tropical easterlies, but at moderate elevations it is characterized by westerly winds. It moves generally from west to east, accompanied by considerable cloudiness. Cumulus congestus and cumulonimbus clouds are usually found in and around the trough lines. Early- and late-season (June and October) hurricanes of the western Caribbean frequently form in polar troughs. See meridional front.
Industry:Weather
In Thornthwaite's 1931 climatic classification, a humidity province in which the principal plant life is drought-resistant short grasses. Köppen called these conditions the steppe climate. Semiarid regions are very susceptible to severe drought.
Industry:Weather
In the western United States, the sandy, salty or mudcaked flat floor of a desert basin having interior drainage, usually occupied by a shallow lake during or after prolonged heavy rains.
Industry:Weather
In the United States, a dry, foehnlike desert wind in southern California, generally blowing from the northeast or east, especially in the pass and river valley of Santa Ana, California, and other nearby passes, where it is further modified as a mountain-gap wind. It is driven by strong pressure gradients from an anticyclone over the Great Basin of the western United States. It blows, often hot and sometimes with great force, from the deserts to the east of the Sierra Nevada Mountains and may carry a large amount of dust. The combination of heat, dryness, and strong winds make it an especially hazardous fire weather condition. It most frequently occurs in late fall and winter (October–March); when it comes in spring, however, it can do great damage to fruit trees.
Industry:Weather
In the Southern Hemisphere, the region of low salinity water between the Antarctic Polar Front and the subantarctic front.
Industry:Weather
In the METAR observation program, a surface observation issued on a nonroutine basis as dictated by changing meteorological conditions.
Industry:Weather
