- 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, ...
In hydrology, the height to which water will rise in an artesian well. The static level of a flowing well is above the ground surface.
Industry:Weather
In meteorology, a forecast that the future weather condition will be the same as the present condition. The persistence forecast is often used as a standard of comparison in measuring the degree of skill of forecasts prepared by other methods, especially for very short projections. See persistence; Compare random forecast, probability forecast.
Industry:Weather
In general, the sense of rotation indicated by curling the fingers of your right hand about the axis denoted by your thumb. When used to describe horizontal circulation in the atmosphere, right-hand rotation is cyclonic in the Northern Hemisphere, anticyclonic in the Southern Hemisphere. See angular velocity.
Industry:Weather
In general, the time interval required for a system exposed to some discontinuous change of environment to undergo the fraction (1 − ''e''<sup>−1</sup>), or about 63%, of the total change of state that it would exhibit after an infinitely long time. For example, a thermometer initially at equilibrium in a bath at temperature ''T''<sub>1</sub> will exhibit an exponential change of temperature with time after being suddenly plunged into a bath at temperature ''T''<sub>2</sub>, theoretically assuming the new temperature ''T''<sub>2</sub> only after an infinitely long time. The finite time interval required for the thermometer to undergo a change of amount (''T''<sub>1</sub> − ''T''<sub>2</sub>)(1 − ''e''<sup>−1</sup>) is called the thermal relaxation time of the thermometer. Occasionally, the fraction 9/10 is used in place of (1 − ''e''<sup>−1</sup>), so contexts must always be checked to be certain of the definition employed in a given case. The definition may also change for an underdamped device. The change of state of such a device may oscillate several times while approaching its final value.
Industry:Weather
In general, the transformation of data from a “raw” form to some usable form. In meteorology, this often refers to the conversion of the observed value of an element to the value that it theoretically would have at some selected or standard level, usually mean sea level. The most common reduction in weather observing is that of station pressure to sea level pressure. Temperature is sometimes reduced to a sea level value, mostly in climatological work. Most calculations of this sort are based upon approximate actual atmospheric conditions or on the standard atmosphere.
Industry:Weather
In analogy to harmonic functions in the plane, the solutions of the Laplace equation in spherical coordinates. Spherical surface harmonics are special sets taken over the surface of a sphere; therefore, the harmonic components are restricted to an integral number of waves over the sphere. Spherical harmonics have been applied in the study of the large-scale oscillations of the atmosphere.
Industry:Weather
In analogy to quasigeostrophic, characterizing a model in which a nondivergent velocity field is used in every context except in the divergence term in the vorticity equation. This velocity field is computed from some steady-state equation such as the balance equation (thus including nonlocal accelerations) and is more general than the geostrophic approximation. The horizontal divergence must, of course, be computed from the equation of continuity or from another equation.
Industry:Weather
In general, the local space rate of change of any potential, as the gravitational potential gradient or the velocity potential gradient. In atmospheric electricity, the electric potential gradient (electric field strength) of the atmosphere is commonly referred to as the atmospheric electric field. The electric field is the negative of the potential gradient.
Industry:Weather
In general, any instability of a rotating fluid system; usually synonymous with inertial instability.
Industry:Weather
In general, any destructive storm, but usually applied to severe local storms in particular, that is, intense thunderstorms, hailstorms, and tornadoes.
Industry:Weather
