- 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 factor ''A'' in the Arrhenius expression for a rate coefficient, ''k'' = ''A'' exp(−''E<sub>a</sub>''/''RT'').
Industry:Weather
The extremely low frequency (ELF) component of some sferics that lags the initial very low frequency (VLF) arrival because of the lower phase velocity at low frequencies. The cause of the slow tail is still controversial. One explanation attributes it to the continuing current. The lightning radiation arrives after the initiating ground stroke because 1) it has components below about 3 kHz in frequencies (necessary for the propagation in the earth–ionosphere waveguide cavity), and 2) it suffers dispersion as a result of the waveguide propagation that broadens the original waveguide impulse, making it look like a tail.
Industry:Weather
The Eulerian equations of motion of a fluid in which the primary dependent variables are the fluid's velocity components. These equations govern a wide variety of fluid motions and form the basis of most hydrodynamical analysis. In meteorology, these equations are frequently specialized to apply directly to the cyclonic-scale motions by the introduction of the so-called filtering approximations. See equations of motion.
Industry:Weather
The extent to which future states of a system may be predicted based on knowledge of current and past states of the system. Since knowledge of the system's past and current states is generally imperfect, as are the models that utilize this knowledge to produce a prediction, predictability is inherently limited. Even with arbitrarily accurate models and observations, there may still be limits to the predictability of a physical system. See chaos.
Industry:Weather
The expression of a field as a sum of spectral modes. The modes may be Fourier modes or spherical harmonics. While a continuous field can be expressed exactly as a sum of an infinite number of modes, in practice it is approximated as a sum of a finite number of modes with the error confined to the higher unrepresented spectral modes.
Industry:Weather
The existence or formation of distinct layers or laminae in a body of water identified by differences in thermal or salinity characteristics (e.g., densities) or by oxygen or nutrient content.
Industry:Weather
The eventual descent to the earth's surface of radioactive matter placed in the atmosphere by an atomic or thermonuclear explosion. Fallout is commonly separated into three classes. 1) Local or close-in fallout occurs in the vicinity (mostly downwind) of the detonation in a matter of hours. It consists mainly of particles greater than 25 microns in diameter, mostly earthen matter rendered radioactive by attachment. Local fallout occurs for an estimated 20%–80% of the total fission products (depending on location and type of detonation). 2) Intermediate or tropospheric fallout remains in the atmosphere for weeks to months, falling out principally by precipitation scavenging, but also by gravitational settling and impingement upon vegetation. Only a few percent of total fission products fall out in this manner. 3) Delayed or stratospheric fallout results from high-yield detonations that thrust their clouds into the stratosphere. Storage times vary from less than one year to as high as ten years, depending upon latitude and altitude of detonation. The particles are of submicron size.
Industry:Weather
The estimation of the amount of rainfall or rainfall rates based on radar measurements or satellite data.
Industry:Weather
The estimation of signal parameters from a sequence of pulses in a radar or lidar system. Incoherent integration, in which the signal intensity from successive pulses is added, is used in simple lidar systems, while coherent integration, with the phase of the signal taken into account, is used in coherent radars.
Industry:Weather
