- 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 zero point of the Kelvin temperature scale, of fundamental significance in thermodynamics and statistical mechanics. It is the linearly extrapolated temperature at which the volume of an ideal gas at constant pressure would vanish. All real gases become liquid or solid at sufficiently low temperatures and maintain a finite volume. Absolute zero on the Kelvin scale corresponds to −273. 15°C.
Industry:Weather
A radiation scale for measurement of solar exitance (irradiance). Prior to 1956, the Ångström Scale (ÅS) (1905) and Smithsonian Scale (SS) (1913) were used. Each scale was calibrated against a different radiation detector (i.e., the Ångström compensation pyrheliometer and water-stirred pyrheliometer, respectively), and yielded slightly different values for the irradiance, with the ÅS reading roughly 3. 5% lower than the SS. The International Pyrheliometric Scale (IPS), defined in 1956, represented a numerical compromise between these two scales. In 1975, the IPS was replaced by the Absolute Radiation Scale (ARS). The ARS is calibrated against six absolute cavity radiometers maintained at the World Radiation Center in Davos, Switzerland. The variation among the six radiometers is about 0. 3%. The IPS was found to give measured irradiance levels that were about 2%–3% percent lower than the more precise ARS.
Industry:Weather
1. Use of sound waves with radar technology for remote probing of the lower atmosphere, up to heights of about 1500 m, for measuring wind speed and direction, humidity, temperature inversions, and turbulence. 2. See sodar.
Industry:Weather
The difference between the instantaneous total pressure and the static pressure, that is, the pressure that would be present in the absence of the acoustic waves. The SI unit is the pascal, but the bar is frequently used.
Industry:Weather
An instrument used to monitor currents by measuring the difference in travel time between each acoustic pulse transmitted in a direction opposite to the flow of a current, and the return pulse.
Industry:Weather
A system of disks or other devices to spread or converge sound waves in a manner analogous to the way an optical lens refracts light.
Industry:Weather
The total reaction of a medium to sound transmission through it, represented by the complex ratio of the sound pressure to the effective flux, that is, particle velocity times surface area through the medium, expressed in acoustic ohms.
Industry:Weather
The average acoustic power transported across a unit area, usually expressed in watts per square meter.
Industry:Weather
The use of acoustic energy to form a representation of a physical object, such as side-scanning sonar imaging of objects on the ocean bottom.
Industry:Weather
Measuring the depth of the ocean by determining the time required for the echo of a sound impulse to return to a point near the surface (i.e., the transmitting ship).
Industry:Weather
