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Sources and sinks of energy in the lower thermosphere
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1974
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Description:The sources and sinks of energy in the subauroral lower thermosphere (80-150 km) have been investigated. Heating and cooling rates due to molecular thermal conduction have been calculated using the U. S. Standard Atmosphere, including variations with altitude, latitude, season, and solar activity. Molecular thermal conduction cools the atmosphere above (typically) 125 km and heats below, although the crossover altitude varies strongly with solar activity. Solar photon absorption in the 40-3000A region has been calculated, with allocation of the initially absorbed energy into ionization, dissociation, excitation, and direct heating. These calculations have been done as a function of altitude, latitude, season, and wavelength. All other known significant energy sources and sinks of energy except for motions have been dealt with also, either by less-detailed calculations than those discussed above or by utilizing previous studies in the literature. These processes include 15y CO2 radiation, 62y atomic oxygen radiation, gravity and tidal wave dissipation, atomic oxygen recombination, 0(^D) deactivation, Joule heating, and electron-ion recombination. Each of these processes, except for Joule heating, is found to be important over at least part of the altitude region considered. Uncertainties in the magnitudes of these processes and in their variations with latitude and season are too large to allow detailed calculations of vertical and horizontal motions. The most important results are the detailed results for molecular thermal conduction and solar photon absorption, and the identification and estimation of other important processes.
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Rights Information:CC0 Public Domain
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Compliance:Library
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