- 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 collective term for small motions in the earth that are unrelated to an earthquake and that have a period of 1. 0–9. 0 s. They are caused by a variety of natural and artificial agents. Certain types of microseisms seem to be closely correlated with pressure disturbances and can be used to locate such disturbances, especially in the case of tropical cyclones. In addition, traffic, industrial activities, and wind flexure of trees and tall structures can create microseisms.
Industry:Weather
In botany, a type of plant life that requires an annual mean temperature of 0°–14°C for normal growth. Such flora are typical of tundra and Boreal woodland.
Industry:Weather
Geomagnetic micropulsations are cyclic fluctuations of the earth's magnetic field in the amplitude range of a fraction of an nT (or gamma) to, on rare occasions, as much as a few tens of nT. Periods range from about 0. 1 sec to 10 minutes.
Industry:Weather
A rain gauge capable of measuring very small amounts of precipitation, amounts that are less than could be measured by an ordinary rain gauge.
Industry:Weather
A unit of length equal to one-millionth of a meter or one-thousandth of a millimeter. The micrometer is a convenient length for measuring wavelengths of infrared radiation, diameters of atmospheric particles, etc.
Industry:Weather
A part of meteorology that deals with observations and processes in the smallest scales of time and space, approximately smaller than 1 km and less than a day (i.e., local processes). Micrometeorological processes are limited to shallow layers of frictional influence (slightly larger-scale phenomena like convective thermals are not part of micrometeorology). Therefore, the subject of micrometeorology is the bottom of the atmospheric boundary layer; namely, the surface layer. Exchange processes of energy, gases, etc. , between the atmosphere and the surface (water, land, plants) are important topics. Therefore, micrometeorology is closely connected with most of the human activities in the atmosphere. Microclimatology describes time averaged (long- term) micrometeorological processes, and micrometeorologists are interested in their fluctuations. Compare mesometeorology, macrometeorology.
Industry:Weather
Colorless, inflammable gas of formula CH<sub>4</sub>; the simplest hydrocarbon. Methane enters the atmosphere as a result of the anaerobic decay of organic matter in, for example, swamps and rice paddies, and is also produced in large quantities by cattle and termites. It is formed along with coal and oil in fossil fuel deposits, and released to the atmosphere on mining. Methane is itself burned as a fuel, being the major constituent of natural gas. The atmospheric mixing ratio of methane is currently about 1. 7 parts per million and has been rising gradually since the industrial era began. The atmospheric lifetime of methane is about eight years. As well as influencing the chemistry of the atmosphere, methane is a strong greenhouse gas and an important source of stratospheric water vapor, and it contributes to global warming.
Industry:Weather
1. A thin interface between two other layers. 2. The very thin (order of 1 mm) layer of air adjacent to the surface for which molecular transport (conduction, diffusion, viscosity) dominates over turbulent transport. See laminar boundary layer.
Industry:Weather
A sharp horizontal temperature contrast of a few degrees Celsius within a width of tens of centimeters to a few meters along the trailing edge of a thermal plume in the surface layer of the atmospheric boundary layer.
Industry:Weather
