- 行业: Weather
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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, ...
A saturation-adiabatic process in which the condensed water substance is removed from the system, and therefore best treated by the thermodynamics of open systems. Meteorologically, this process corresponds to rising air from which the moisture is precipitating. Descent of air so lifted becomes by definition a dry-adiabatic process. See pseudoadiabatic process.
Industry:Weather
A sea in which a large number of wave components are present, a result of the random processes involved in wave generation. The behavior of the waves may be represented statistically in terms of a wave spectrum. Most sea states may be described as random seas.
Industry:Weather
A sawtooth temperature pattern in a time series measured at the bottom of the atmospheric boundary layer. Each tooth or ramp (gradual linear increase in temperature followed by a rapid decrease) is associated with the passage of a surface-layer convective plume.
Industry:Weather
A satellite with an orbit that lies in a plane passing through the center of the earth and is inclined to the equatorial plane such that the subpoint track traverses polar latitudes on every orbit.
Industry:Weather
A remote-sensing instrument used for the determination of cloud heights. It operates on the principle of pulse radar, employing visible light rather than radio waves. See ceilometer, laser ceilometer, cloud-height indicator.
Industry:Weather
A satellite system jointly developed by NASA and private industry to measure ocean color for research and operations. Ocean color reveals the presence and concentration of phytoplankton, sediments, and dissolved organic chemicals in the uppermost layers of the ocean. Measurements are made with SeaWiFS, a multispectral imaging spectrometer. ''SeaStar'' was successfully launched on 1 August 1997.
Industry:Weather
A satellite in an orbit that precesses 360° during the course of the year, permitting the satellite to obtain views of a given geographical area at the same local time each day. A sun-synchronous satellite always crosses the equator on the ascending node at the same local solar time.
Industry:Weather
A remote-recording thermograph with a sensing element that may be buried at various depths in the earth. See soil thermometer.
Industry:Weather
A remote sensing system that relies on the emission of natural levels of radiation from the target. Most satellite-borne meteorological instruments are passive systems.
Industry:Weather
A relatively slow-moving, nonluminous lightning streamer, the existence of which has been postulated but not verified, to provide a physical explanation for the observed intermittent mode of advance of a stepped leader as it initiates a cloud-to-ground lightning discharge. Whereas the stepped leader descends at an average speed of the order of 10<sup>5</sup> m s<sup>−1</sup> during its downward motion, it advances only about 50 m at a time with a speed greater than average and then pauses for 50–100 μs before resuming its downward movement. The average downward speed has been associated with an invisible streamer, the pilot streamer, which is postulated to descend at a uniform speed only slightly in excess of the ionizing speed of electrons in air and lay down a trail of weak residual ionization along which the stepped leader moves very rapidly in a pulsating manner. The idea of a pilot leader has been supplanted by more modern theory based on studies of sparks over long distances in the laboratory.
Industry:Weather
