- 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, ...
The geometric characteristic of a surface associated with its efficiency as a momentum sink for turbulent flow, due to the generation of drag forces and increased vertical wind shear. In micrometeorology, the surface roughness is usually measured by the roughness length, a length scale that arises as an integration constant in the derivation of the logarithmic wind profile relation. In neutral stability the logarithmic wind profile extrapolates to zero wind velocity at a height equal to the surface roughness length. Several formulas exist to parameterize this length scale as a function of the roughness element geometry (e.g., spacing and silhouette area). Tabulated values for various surface types are published in most micrometeorological texts. See momentum flux, zero-plane displacement.
Industry:Weather
The general term used to describe the conversion of a reduced molecule to an oxidized form in the presence of molecular oxygen via a set of chemical reactions that are initiated by photolysis. In the atmosphere, hydrocarbons are converted to carbon monoxide, CO, and carbon dioxide, CO<sub>2</sub>, via photooxidation.
Industry:Weather
The general state of the atmosphere as described by the major features of synoptic charts.
Industry:Weather
The general abbreviation for an instrument of viewing, such as telescope, microscope, or oscilloscope. In radar installations, the cathode-ray oscilloscope indicators are commonly referred to as scopes or radarscopes.
Industry:Weather
The frequency band, above or below the carrier frequency, that is produced by the process of modulation.
Industry:Weather
The formula relating dimensionless groups in similarity theory. While Buckingham Pi theory allows one to identify which dimensionless groups of variables might be relevant to a particular flow situation, it does not give a formula relating these groups. Such a formula is found empirically.
Industry:Weather
The forecasting of atmospheric phenomena using a spectral model. The model may be a simple shallow water model or a complex three-dimensional system with full parameterized physics. The model predicts the atmospheric variables in spectral space, but they are generally transformed to physical space for display, dissemination, and verification.
Industry:Weather
The force per unit area on a surface due to the airflow above it. For a mean wind speed ''U<sub>r</sub>'' at a reference height ''z<sub>r</sub>'', drag coefficient ''C<sub>D</sub>''(''z<sub>r</sub>'') for that same reference height, and air density , the surface wind stress τ is given by τ = ''C<sub>D</sub>''(''z<sub>r</sub>'')''U<sub>r</sub>''<sup>2</sup>.
Industry:Weather
The focused electromagnetic emissions from a radar antenna. The beam is defined by the main lobe of the antenna pattern.
Industry:Weather
The flux of energetic protons into the upper atmosphere from the radiation belts, the outer magnetosphere, or the sun.
Industry:Weather
