- 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 fraction of sea surface area covered by ice, usually expressed in tenths. For example, 9/10 concentration implies that 90% of the local area is ice covered, with the remaining 10% being open water.
Industry:Weather
An apparent force on moving particles in a noninertial coordinate system, that is, the Coriolis acceleration as seen in this (relative) system. Such a force is required if Newton's laws are to be applied in this system. In meteorology the Coriolis force per unit mass arises solely from the earth's rotation, and is equal to −2Ω × u, where Ω is the angular velocity of the earth and u is the (relative) velocity of the particle. Thus the Coriolis force acts as a deflecting force, normal to the velocity, to the right of the motion in the Northern Hemisphere and to the left in the Southern Hemisphere. It cannot alter the speed of the particle. The three components toward east, north, and zenith are, respectively, 2Ω (v sinφ − w cosφ), −2Ωu sinφ, and 2Ωu cosφ, where u, v, w are the component velocities and φ the latitude. Since the Coriolis force is in effect proportional to the speed, its importance in any given atmospheric motion may be judged from the representative speed and duration of the motion. See inertial force.
Industry:Weather
An intimate mixture of two substances, one of which, called the dispersed phase (or colloid), is uniformly distributed in a finely divided state through the second substance, called the dispersion medium (or dispersing medium). The dispersion medium may be a gas, a liquid, or a solid and the dispersed phase may also be any of these, with the exception of one gas in another. A system of liquid or solid particles colloidally dispersed in a gas is called an aerosol. A system of solid substance or water-insoluble liquid colloidally dispersed in liquid water is called a hydrosol. There is no sharp line of demarcation between true solutions and colloidal systems or between mere suspensions and colloidal systems. When the particles of the dispersed phase are smaller than about 10−3 μm in diameter, the system begins to assume the properties of a true solution; when the particles dispersed are much greater than 1 μm, separation of the dispersed phase from the dispersing medium becomes so rapid that the system is best regarded as a suspension. According to the latter criterion, natural clouds in the atmosphere should not be termed aerosols; however, since many cloud forms apparently exhibit characteristics of true colloidal suspensions, this strict physico-chemical definition is often disregarded for purposes of convenient and helpful analogy. Condensation nuclei and many artificial smokes may be regarded as aerosols.
Industry:Weather
The fraction of sea surface area covered by ice, usually expressed in tenths. For example, 9/10 concentration implies that 90% of the local area is ice covered, with the remaining 10% being open water.
Industry:Weather
(Also called comfort standard. ) The ranges of indoor temperature, humidity, and air movement, under which most persons enjoy mental and physical well-being. As represented on comfort charts of the American Society of Heating and Air Conditioning Engineers, comfort zones are areas bounded by curves of effective temperature and relative humidity. The limiting conditions vary somewhat according to season and to the native climate of the person or group. In the United States the comfort zone with normal ventilation lies between air temperatures of about 17° and 24°C (63° and 75°F) at a relative humidity of 70%, and 19°C (67°F) at a relative humidity of 30%, giving an effective temperature within a few degrees of 19°C (67°F). The limits, however, vary with the season, being higher in summer than in winter. In the United Kingdom, the comfort zone is centered on an effective temperature of about 16°C (60°F). In the Tropics the comfort zone lies between the same limits of relative humidity, but at air temperatures around 26°C (78°F). Compare comfort curve.
Industry:Weather
An intimate mixture of two substances, one of which, called the dispersed phase (or colloid), is uniformly distributed in a finely divided state through the second substance, called the dispersion medium (or dispersing medium). The dispersion medium may be a gas, a liquid, or a solid and the dispersed phase may also be any of these, with the exception of one gas in another. A system of liquid or solid particles colloidally dispersed in a gas is called an aerosol. A system of solid substance or water-insoluble liquid colloidally dispersed in liquid water is called a hydrosol. There is no sharp line of demarcation between true solutions and colloidal systems or between mere suspensions and colloidal systems. When the particles of the dispersed phase are smaller than about 10−3 μm in diameter, the system begins to assume the properties of a true solution; when the particles dispersed are much greater than 1 μm, separation of the dispersed phase from the dispersing medium becomes so rapid that the system is best regarded as a suspension. According to the latter criterion, natural clouds in the atmosphere should not be termed aerosols; however, since many cloud forms apparently exhibit characteristics of true colloidal suspensions, this strict physico-chemical definition is often disregarded for purposes of convenient and helpful analogy. Condensation nuclei and many artificial smokes may be regarded as aerosols.
Industry:Weather
In the Philippines, a fresh or strong (less than Beaufort force 8) south to southwest wind, accompanied by heavy rain and severe squalls. It is experienced most frequently in June and July and may persist for several days. It occurs when an extensive trough of low pressure runs from east to west or east-northeast to west-southwest, north of Manila, and is either stationary or moving slowly northward.
Industry:Weather
In the Philippines, a fresh or strong (less than Beaufort force 8) south to southwest wind, accompanied by heavy rain and severe squalls. It is experienced most frequently in June and July and may persist for several days. It occurs when an extensive trough of low pressure runs from east to west or east-northeast to west-southwest, north of Manila, and is either stationary or moving slowly northward.
Industry:Weather
A slowly varying change of climate about a mean that recurs with some regularity but is not necessarily periodic. The term “cycle” is used in climatology more loosely than in other physical sciences. It implies quasiperiodic behavior without any real precision in the recurrence of events. It usually indicates only that the event is more probable at the peak of the cycle than at the trough. The existence of numerous cycles has been postulated, ranging from those with timescales of geological length down to a few years.
Industry:Weather
A slowly varying change of climate about a mean that recurs with some regularity but is not necessarily periodic. The term “cycle” is used in climatology more loosely than in other physical sciences. It implies quasiperiodic behavior without any real precision in the recurrence of events. It usually indicates only that the event is more probable at the peak of the cycle than at the trough. The existence of numerous cycles has been postulated, ranging from those with timescales of geological length down to a few years.
Industry:Weather
