- Settore: 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 principle that, in the absence of forces, absolute momentum is a property that cannot be created or destroyed. See Newton's laws of motion.
Industry:Weather
The principle that the total energy of an isolated system remains constant. This principle takes into account all forms of energy in the system; it therefore provides a constraint on the conversions from one form to another. See energy equation for formulations applicable to meteorology.
Industry:Weather
The principle that absolute angular momentum is a property that cannot be created or destroyed but can only be transferred from one physical system to another through the agency of a net torque on the system. As a consequence, the absolute angular momentum of an isolated physical system remains constant. The principle of conservation of angular momentum can be derived from Newton's second law of motion.
Industry:Weather
The principle (of Newtonian mechanics) that states that mass cannot be created or destroyed but only transferred from one volume to another. In meteorology, this principle is generally expressed in the form of the equation of continuity.
Industry:Weather
The prediction of various aspects of the climate of a region during some future period of time. Climate predictions are generally in the form of probabilities of anomalies of climate variables (e.g., temperature, precipitation), with lead times up to several seasons (see climate anomaly). The term “climate projection” rather than “climate prediction” is now commonly used for longer- range predictions that have a higher degree of uncertainty and a lesser degree of specificity. For example, this term is often used for “predictions” of climate change that depend on uncertain consequences of anthropogenic influences such as land use and the burning of fossil fuels.
Industry:Weather
The practice of releasing radar chaff, which is aluminum or aluminum coated plastic strips or needles, into the atmosphere for the purpose of obtaining a strong radar reflecting signal in an otherwise weakly reflecting environment. Chaff seeding, as a research technique, has been used to study the motion, deformation, transport, and mixing processes of the atmosphere on scales from a few meters to a few kilometers. Chaff seeding has also been used on the hypothesis that corona discharge from the needle tips could reduce lightning from thunderstorms. See window.
Industry:Weather
The phenomenon that the equilibrium positions of the air–water interfaces in a system of pores are dependent on whether the system is increasing or decreasing in water content (i.e., the wetting history).
Industry:Weather
The physical process causing cloud electrification. On the particle scale, the process can include particle collisions with selective charge transfer and particle capture of small ions. On the cloud scale, the process can include gravity-driven differential particle motions and convective transport of charged air parcels.
Industry:Weather
The periodic elements comprising a layer cloud with a regular array of cloud and a connecting lattice of clear air.
Industry:Weather
The period between astronomical sunrise or sunset and the time when the sun's unrefracted center is at elevation h0 = −6°. Local topography above the astronomical horizon will make local sunset occur before astronomical sunset. During a clear evening's civil twilight, horizontal illuminance decreases from ∼585–410 lux to ∼3. 5–2 lux. As is true of nautical and astronomical twilight, civil twilight's length varies greatly with latitude and time of year. At h0 = −6°, the ambient illuminance under clear skies historically was deemed just adequate for doing outdoor work without artificial illumination. However, perceptually demanding tasks, such as driving an automobile, require higher illuminances. Also at h0 = −6°, luminances near the clear sky's zenith are low enough to make the brightest stars visible. Compare astronomical twilight.
Industry:Weather
