- 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, ...
Generally, any radar that is suitable or can be used for the detection of precipitation or clouds. The general qualifications for weather radars are 1) a wavelength between 1 and 30 cm, 2) pulsed transmission with high peak power (kilowatts to megawatts), 3) relatively narrow beamwidths, 4) pulse lengths of a few microseconds or less, 5) pulse repetition frequencies of several hundred hertz, and 6) automatic azimuth or elevation angle scanning. Electronic circuits and signal processing permit the quantitative measurement of radar reflectivity factor or signal strength and, for Doppler radars, the radial velocity. Compare wind profiler, MST radar.
Industry:Weather
Generally, any of the quasi-permanent, large-scale wind systems of the atmosphere, for example, the westerlies, trade winds, equatorial easterlies, polar easterlies, etc.
Industry:Weather
General term for an instrument that records the vertical electric current in the atmosphere.
Industry:Weather
General term for a small-scale, rotating column of air. More specific terms are dust whirl, dust devil, waterspout, and tornado.
Industry:Weather
General name for apparatus, such as a tracking radar, used in following and recording the position of objects in the sky. A theodolite and an observer form an optical tracking system used in pilot balloon runs.
Industry:Weather
General name for an instrument designed to measure the vertical component of the wind vector. Compare vertical anemometer.
Industry:Weather
General name for an instrument designed to measure the vertical component of the wind speed. See anemoclinometer; Compare vertical-axis anemometer.
Industry:Weather
Front occurring in the warm season between a flow of oceanic trade winds and warm air from the continents.
Industry:Weather
For a point light source at night, the smallest illuminance ''E<sub>thresh</sub>'' at the observer that can be seen for a given surrounding luminance and state of dark adaptation. Although the threshold illuminance is not a constant, a dark-adapted observer can usually see a nonflashing light that produces ∼1. 5×10<sup>−7</sup> lux at the eye. See Also Allard's law, night visual range.
Industry:Weather
