| Section S | S index | 1071-1079 of 1376 terms |
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Stratospheric Aerosol Gas Experiment—(Abbreviated SAGE.) A limb sounding instrument that was first flown as a Small Applications Explorer Mission in 1979. Since this initial mission, a series of SAGE instruments have been flown on a variety of satellites. In all cases, the SAGE instruments measure vertical profiles of aerosol and gas concentrations by measuring the extinction of sunlight during satellite sunrises and sunsets. SAGE II was launched in October 1984 on the ERBS, and SAGE III will be flown on a number of satellites as part of NASA's EOS program. Current plans call for placing SAGE III on a Russian Meteor platform, as well as on the International Space Station.
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Stratospheric Aerosol Measurement—(Abbreviated SAM.) A single channel sun photometer centered at 1 micron used to measure aerosol extinction above the earth tangent point by looking at the sun during spacecraft sunrise and sunset. SAM was initially tested as a hand-held sun photometer on Apollo–Soyuz in 1975. A follow- on SAM-II instrument was carried onboard Nimbus-7 (launched October 1978).
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Stratospheric and Mesospheric Sounder—(Abbreviated SAMS.) A multichannel infrared limb sounder on Nimbus-7 (launched October 1978) designed to extract vertical temperature soundings from upper atmospheric emissions.
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stratospheric coupling—The interaction between disturbances in the stratosphere and those in the troposphere. The interaction can take the form of dynamic forcing and/or an exchange of mass.
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stratospheric oscillation—Traveling wave in the stratosphere with a period of between four and five days and forced by diabatic heating in the troposphere. The diabatic forcing is manifested as cloud-brightness oscillations that are particularly prominent at 5°–10°N in the northern winter, indicating that they are oscillations in the intertropical convergence zone.
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Stratospheric Sounding Unit—(Abbreviated SSU.) A three-channel infrared sounder on operational NOAA polar-orbiting satellites. The three channels are used to determine profiles of temperature in the stratosphere.
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stratospheric steering—The steering of lower-level atmospheric disturbances along the contour lines of the tropopause, which lines are presumably roughly parallel to the direction of the wind at tropopause level.
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stratospheric sulfate layer—( Also called Junge aerosol layer.) A region in the lower stratosphere (approximately 15–25 km in altitude and worldwide) where submicrometer-sized particles composed of aqueous sulfuric acid are present. Oxidation of sulfur compounds (primarily carbonyl sulfide, OCS, and sulfur dioxide, SO2) is believed to be the source of sulfuric acid (H2SO4). Volcanic eruptions directly inject large quantities of H2S or SO2 into the stratosphere, causing large increases in the amount of particulate sulfuric acid. The particles undergo a slow falling-out process (timescale of years) into the lower atmosphere. Because these sulfuric acid particles are present in the ozone layer, heterogeneous chemical reactions that occur on them can have a significant effect on ozone by influencing the abundance of trace species that affect ozone concentrations.
Junge, C. E., C. W. Chagnon, and J. E. Manson, 1961: Stratospheric aerosols. J. Meteor., 18, p.81.
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stratospheric warming—(Also called sudden warming.) A rise in temperature of the stratosphere in the polar region in late winter resulting from enhanced propagation of energy from the troposphere by planetary-scale waves. Temperatures near 50 mb can increase by as much as 40°C in just a few days.
Andrews, D. F., J. R. Holton, and C. B. Leovy, 1987: Atmosphere Dynamics, 259–294.
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stratus fractus—(Previously called fractostratus.) See fractus.
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