- 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 height of the lowest opaque cloud layer reported as broken (5/8 to 7/8 coverage) or overcast. Expressed in above ground level (AGL) heights. See ceiling.
Industry:Weather
The gradual deterioration of material by chemical processes, such as oxidation or attack by acids; if caused by an atmospheric effect, a form of weathering. Of great significance is the corrosion due to the combined effects of atmospheric temperature, humidity, and suspended impurities, for example, the rusting of iron, the direct effects upon a surface wetted by acid water, or, indirectly, the rotting of wood caused by the action of fungi or bacteria in the soil and in enclosed spaces. Compare corrasion, erosion.
Industry:Weather
The grouping of cloud height in the WMO classification: high etage (3–8 km); middle etage (2–4 km); and low etage (surface to 2 km).
Industry:Weather
The general term for instruments that measure the height of cloud bases. Cloud-height indicators may be classified according to their principle of operation. One class of instrument is based on height determination by means of the principle of triangulation. A beam of light projected from the ground onto the base of the cloud is observed visually or electrically from a remote point. The height of the cloud is determined trigonometrically from a measurement of the angle defined by the light projector, the observation point, and the light spot on the cloud plus the distance between the light projector and the observation point. Examples of instruments based on this principle are the ceilometer and the ceiling light. A second class of instrument is based on pulse techniques. The time required for a pulse of energy to travel from a radiator located on the ground to the cloud base and back to the ground is measured electrically. The height of the cloud is computed from this transit time and a knowledge of the propagation velocity of the pulse. Instruments based on this principle include the pulsed-light cloud-height indicator and vertically directed cloud-detection radar.
Industry:Weather
The general term for anemometers operating on the principle that the heat transfer to air from an object at an elevated temperature is a function of the air speed. Examples are hot-wire and hot-film anemometers.
Industry:Weather
The general geometric configuration of atmospheric circulation usually applied, in synoptic meteorology, to the large-scale features of synoptic charts and mean charts. Compare pressure pattern.
Industry:Weather
The fundamental constituents of clouds responsible for their visibility, consisting of water droplets and/or ice crystals having small (less than 25 cm s−1) fall velocity through the air.
Industry:Weather
The front between the Antarctic Circumpolar Current and the narrow region of westward movement close to the Antarctic coast. It extends from the Ross Sea eastward to the Weddell Sea, where it separates the cyclonic movement of the Weddell Sea from the Circumpolar Current, and is sometimes also called the Weddell Gyre Boundary.
Industry:Weather
The frequency of the unmodulated transmitted wave of a radio or radar transmitter.
Industry:Weather
The fraction of solar radiation reflected directly by clouds in the atmosphere. This represents a major part of the albedo of the earth. On the average, the earth reflects 31 units of solar radiation back to the space for every 100 units received (thus, the total earth albedo is 0. 31). The cloud albedo accounts for 23 units of the 31. For individual clouds, local albedo may be in excess of 0. 7.
Industry:Weather
