- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
- Company Profile:
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 radiation chart developed by W. M. Elsasser for the graphical solution of the radiative transfer problems of importance in meteorology. Given a radiosonde record of the vertical variation of temperature and water vapor content, one can find with this chart such quantities as the effective terrestrial radiation, net flux of infrared radiation at a cloud base or a cloud top, and radiative cooling rates.
Industry:Weather
A polarization state of an electromagnetic wave in which the electric field vector at a point in space describes an ellipse. Definition of the polarization state includes the direction of rotation of the electric field (right or left), the ellipticity, and the orientation of the major axis of the ellipse. Compare circular polarization.
Industry:Weather
Transient laterally extensive illumination of the airglow layer, at about 90 km, over thunderstorms, and associated with the electromagnetic pulse from the return stroke of a lightning flash to ground.
Industry:Weather
A vector quantity with nonzero components in the latitude–height plane, the direction and magnitude of which determine the relative importance of eddy heat flux and momentum flux. When the Eliassen–Palm flux (EPF) vector points upward, the meridional heat flux dominates; when the EPF vector points in the meridional direction, the meridional flux of zonal momentum dominates. The divergence of the Eliassen–Palm flux is more frequently used as a diagnostic tool, as it is proportional to the eddy potential vorticity flux. In the special case when the EPF divergence is zero, as for steady, frictionless, linear waves, thermal wind balance is maintained in an idealized zonally symmetric atmosphere through the induction of a mean meridional circulation, even though the waves produce significant eddy heat and momentum fluxes.
Industry:Weather
The ratio of power received in the transmission channel to power received in the orthogonal channel of a dual-channel radar, when an elliptically polarized signal is transmitted. For a weather target, this ratio depends, in general, on the ratio of the major to the minor axis of the polarization ellipse, the orientation of the ellipse, and the depolarizing characteristics of the hydrometeors that constitute the target. Typically, the ratio will be less than unity (or a negative decibel quantity) when the major and minor axes are comparable in size and the polarization ellipse is close to circular, but will be greater than unity (or a positive decibel quantity) as the polarization ellipse becomes sufficiently elongated on either of its axes. A greater depolarization ratio is achievable with elliptical than with circular polarization by matching the axial ratio and the orientation of the transmitted signal to the depolarizing characteristics of the target. Compare cancellation ratio, circular depolarization ratio.
Industry:Weather
Measures the volume (capacity) of a reservoir below a certain elevation.
Industry:Weather
Imaginary curves in space tangent to the electric field at each point; analogous to streamlines in fluid mechanics.
Industry:Weather
The angle between the horizon and a point above the horizon, measured along the arc that passes through the zenith and the point in question. In astronomy this is termed altitude. Compare azimuth, depression angle, zenith distance.
Industry:Weather
Convection that originates from an atmospheric layer above the boundary layer.
Industry:Weather
