- 行业: Weather
- Number of terms: 60695
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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, ...
A temperature inversion (temperature rising with height) in the atmosphere, encountered upon vertical ascent through a sloping front (or frontal zone).
Industry:Weather
A synoptic chart showing the height of the 0°C constant-temperature surface by means of contour lines.
Industry:Weather
A system of approximate hydrodynamical equations from which certain families of solutions of the original equations, normally corresponding to timescales shorter than those of interest, are automatically excluded. See filtering approximations.
Industry:Weather
A strong, low-level wind through either a relatively level channel between two mountain ranges or a gap in a mountain barrier; originally applied to strong (10–20 m s−1) easterly winds through the Strait of Juan de Fuca between the Olympic Mountains of western Washington State and the mountains of Vancouver Island, British Columbia, Canada. There they have been defined as “a flow of air in a sea level channel that accelerates under the influence of a pressure gradient parallel to the axis of the channel. ” As in the case of mountain- gap winds, this term has also been applied to pressure-gradient winds accelerating through a gap in a mountain barrier. The pressure gradient often results from a stable, post-cold-frontal anticyclone approaching the barrier and being partially blocked (see blocking) as it ascends the barrier, except for the flow through the gap or channel. The tehuantepecer of Central America is a well- known gap wind by this definition. These flows have sometimes been referred to as jet-effect wind and canyon wind.
Industry:Weather
A technique for smoothing the statistical fluctuations in power spectra, thus improving the detectability of signals in noise. Two essentially equivalent techniques can be used on power spectra derived from MN data points:
M spectra each containing N spectral power density points are averaged together in each frequency bin, producing a single averaged N-point spectrum. The spectral points in a single MN-point spectrum are averaged together in groups of M points, also producing a single averaged N-point power. Such techniques are widely used for Doppler spectrum measurements in wind profilers and MST radars.
Industry:Weather
A system of spherical coordinates based on the best fit of a centered dipole to the actual magnetic field of the earth. The field due to an earth-centered magnetic dipole is given by the first three terms of the spherical harmonic expression of the IGRF (or DGRF) model.
Industry:Weather
A system of measurement in which the fundamental units are foot, pound, and second.
Industry:Weather
A system of logic dealing with the concept of partial truth with values ranging between “completely true” and “completely false. ”
It is often confused with probability, which represents the degree of possibility of an occurrence. Fuzzy logic sets need not sum to 1 as do probabilities.
Industry:Weather
A storm warning, for marine interests, of sustained winds of 28–47 knots inclusive (32–54 mph) either predicted or occurring and not associated with tropical cyclones. The storm-warning signals for this condition are 1) two triangular red pennants by day and 2) a white lantern over a red lantern by night.
Industry:Weather
