- Industria: 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, ...
Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays. Wavelengths of UV radiation range from 5 to 400 nm, which may be further subdivided into the UV-A, UV-B, and UV-C ranges. UV radiation contains about 9% of the total energy of the solar electromagnetic spectrum. Such radiation has marked actinic and bactericidal action, and produces fluorescence in a number of substances. Ultraviolet radiation from the sun is responsible for many complex photochemical reactions characteristic of the upper atmosphere, for example, the formation of the ozone layer through ultraviolet dissociation of oxygen molecules followed by recombination to form ozone. The absorption of UV by stratospheric ozone and upper atmospheric oxygen is sufficiently strong that very little ultraviolet radiation with wavelengths shorter than about 300 nm reaches the earth's surface.
Industry:Weather
The basis for civil timekeeping. It is formally defined by a mathematical formula which relates UT to Greenwich mean sidereal time. Depending on the context, universal time and UT are commonly used to mean 1) UT0, which is dependent on the observer's location; 2) UT1, which removes the effect of the motion of the geographic pole; or 3) coordinated universal time (UTC). Since 1 January 1972, weather services have used UTC as the standard of time. See Also zone time.
Industry:Weather
A satellite designed to study chemistry, dynamics, and energetics of the stratosphere, mesosphere, and lower thermosphere. ''UARS'' was launched in September 1991. ''UARS'' instruments include the cryogenic limb spectrometer of etalon array, an improved stratospheric and mesospheric sounder, a microwave limb sounder, a halogen hide experiment, a high-resolution Doppler imager, a wind imaging interferometer, a solar–stellar irradiance experiment of comparison, a solar ultraviolet spectral irradiance monitor, a particle environment monitor, and the active cavity radiometer monitor of irradiance.
Industry:Weather
A linear beam amplifier tube used in medium-power radar transmitters. In a TWT, a stream of electrons interacts continuously or repeatedly with a guided electromagnetic wave moving substantially in synchronism with it and in such a way that there is a net transfer of energy from the stream to the wave. A TWT is characterized by high bandwidth but has somewhat lower gain, power, and efficiency than a klystron.
Industry:Weather
The Doppler velocity signature of a tornado or of an incipient tornado-like circulation aloft. As the signature occurs when the radar beam is wider than the vortex, the measured Doppler velocities are weaker than the rotational velocities within the vortex and the apparent core diameter is larger than that of the vortex. The signature, which may extend throughout a considerable vertical depth, is ideally characterized by extreme Doppler velocity values of opposite sign separated in azimuth by the equivalent of one beamwidth. However, since most radars display and record Doppler velocity values at discrete azimuthal intervals, the extreme Doppler velocity values are usually at azimuthally adjacent positions that are roughly one beamwidth apart. If the centers of the radar beam and the vortex coincide, the signature includes a zero Doppler velocity value that separates the extreme values.
Industry:Weather
An observing system utilizing lightweight balloons to record weather data that were transmitted through ''Nimbus''''-6'', launched in June 1975, to a ground station.
Industry:Weather
A graph with temperature as ordinate and salinity as abscissa, on which the points observed at a single oceanographic serial station are joined by a curve (the T–S curve).
Industry:Weather
The amount of solar radiation received outside the earth's atmosphere on a surface normal to the incident radiation, and at the earth's mean distance from the sun. Reliable measurements of solar radiation can only be made from space and the precise record extends back only to 1978. The generally accepted value is 1368 W m<sup>−2</sup> with an accuracy of about 0. 2%. Variations of a few tenths of a percent are common, usually associated with the passage of sunspots across the solar disk. The solar cycle variation of TSI is on the order of 0. 1%.
Industry:Weather
Given measurements at a single location of ''T''(''z'') and ''S''(''z''), oceanographers often plot ''T''(''z'') versus ''S''(''z''), showing the depth dependence only parametrically. The main reason for doing this is that water masses generally are characterized by their location on the ''T''–''S'' plane, and so can be identified by plotting a ''T''–''S'' curve.
Industry:Weather
