- 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 mean velocity in the Doppler spectrum; that is, the first moment of the Doppler spectrum expressed in terms of velocity. See Doppler spectral moments.
Industry:Weather
The local name, taken from the Matanuska River, for a strong, gusty, northeast wind that occasionally occurs during the winter in the vicinity of Palmer, Alaska.
Industry:Weather
A system introduced by Marsden early in the nineteenth century for showing the distribution of meteorological data on a chart, especially over the oceans. A Mercator map projection is used, the world between 80°N and 70°S latitudes being divided into Marsden squares each of 10° longitude. These squares are systematically numbered to indicate position. Each square may be divided into quarter squares, or into 100 one-degree subsquares numbered from 00 to 99 to give the position to the nearest degree.
Industry:Weather
A system that divides a Mercator chart of the world into squares of 10° latitude by 10° longitude. Each square is numbered and then subdivided into 100 one-degree squares numbered from 00 to 99. These 100 one-degree squares are applied to the eight octants of the globe. Marsden squares are mainly used for identifying the geographic position of meteorological data over the oceans.
Industry:Weather
The ''Z''–''R'' relationship developed by J. S. Marshall and W. M. Palmer (1948) consistent with an exponential drop-size distribution. The relationship is ''Z'' = 200''R''<sup>1. 6</sup>, where ''Z'' (mm6 m−3) is the reflectivity factor and ''R'' (mm h<sup>−1</sup>) is the rainfall rate. The relationship is sometimes generalized to the form Z = aR<sup>b</sup>, where ''a'' and ''b'' are adjustable parameters.
Industry:Weather
A sunshine recorder of the type in which the timescale is supplied by a chronograph. It consists of two bulbs, one of which is blackened, that communicate through a glass tube of small diameter. The tube is partially filled with mercury and contains two electrical contacts. When the instrument is exposed to sunshine, the air in the blackened bulb is warmed more than that in the clear bulb. The warmed air expands and forces the mercury through the connecting tube to a point where the electrical contacts are shorted by the mercury. This completes the electrical circuit to the pen on the chronograph. The Marvin sunshine recorder is equally sensitive to the direct rays of the sun and to diffuse radiation from the sky (the heat from the latter at midday in overcast may be more than that from direct sunshine in the early morning); thus, the instrument is not without ambiguities. It is standard equipment at National Weather Service stations.
Industry:Weather
A stochastic process with a finite number of states in which the probability of occurrence of a future state is conditional only upon the current state; past states are inconsequential. In meteorology, Markov chains have been used to describe a raindrop size distribution in which the state at time step ''n'' + 1 is determined only by collisions between pairs of drops comprising the size distribution at time step ''n''.
Industry:Weather
A process for generating a time series where the value at any new time depends only on the previous value plus some random component.
Industry:Weather
