- Industry: Weather
- Number of terms: 60695
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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 pressure exerted by the atmosphere as a consequence of gravitational attraction exerted upon the “column” of air lying directly above the point in question. As with any gas, the pressure exerted by the atmosphere is ultimately explainable in terms of bombardment by gas molecules; it is independent of the orientation of the surface on which it acts. Atmospheric pressure is one of the basic meteorological elements. It is measured by many varieties of barometer and is expressed in several unit systems. The most common unit used is the millibar (1 millibar equals 1000 dynes cm−2). Unique to the science of meteorology is the use of inches (or millimeters) of mercury, that is, the height of a column of mercury that exactly balances the weight of the column of atmosphere the base of which coincides with that of the mercury column. Also employed are units of weight per area and units of force per area. A standard atmosphere has been defined in terms of equivalence to each of the above unit systems, and it is used as a unit itself. See actual pressure, station pressure, sea level pressure.
Industry:Weather
A minor but important constituent (chemical symbol O3) of the earth's atmosphere. While it is essential for life as we know it today, it is also a toxic gas that can result in significant physiological and ecological damage if exposures exceed critical limits. In both the stratosphere and troposphere, ozone concentration levels depend on many linked chemical and meteorological mechanisms, which vary significantly with space and time. Human pollutant emissions often perturb these linkages, resulting in significant increases or decreases in ozone concentration. While many facets of ozone's atmospheric behavior are well understood, a large number of important uncertainties remain, the resolution of which will require substantial combined efforts by the meteorological and chemical communities. See air pollution.
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
大气边界层的上面的科学研究。除了上部空气数据 （温度、 风力、 压力等） 的演示文稿，它包括高空变量的空间和时间变化的原因分析。更常见的演示文稿当中的手段在指定的时间段 （几个月、 季、 年) 空间地图。请参阅气候学。
Industry:Weather
先后在时间中生成一个变量的值。连续气压跟踪是连续时间系列的示例，虽然每小时压力的序列是离散时间系列的一个示例。以图形化的方式，时间序列通常是以时间为横坐标和纵坐标作为函数的值绘制的。时间序列可以是固定或非平稳。为平稳时间系列激励系列的实际动态是不断从一个时期到下一个。非平稳时间系列不断变化的动态变化和这种系列是较不容易受到统计分析。
Industry:Weather
The range of ambient temperature in which normal metabolism provides enough heat to maintain an essentially constant body temperature in homeothermic animals. The limits of the zone depend on the species and breed of an animal and its age, sex, degree of acclimatization, how it is fed, and even the time of day. The zone is narrow for the young of a species (e. G. , 29°–30°C for a chick) and wide for a well- fed large adult (e. G. , −30° to +25°C for a cow).
Industry:Weather
能量通量和温度梯度 （见热传导） 之间的比例因子。热导率在某种程度上是一种内在特性的一种媒介，但可能依赖于温度。空气的导热系数是大于水汽和两个增加的 50%左右 （大约） 作为绝对温度的平方根。液态水的导热系数是空气的 25 倍左右。热导率的固体，尤其是金属，是数千倍比风更大。
Industry:Weather
