Empirical model of global thermospheric temperature and composition based on data from the Ogo 6 quadrupole mass spectrometer
Abstract
An empirical global model for magnetically quiet conditions has been derived from longitudinally averaged N2, O, and He densities by means of an expansion in spherical harmonics. The data were obtained by the Ogo 6 neutral mass spectrometer and cover the altitude range 400-600 km for the period June 27, 1969, to May 13, 1971. The accuracy of the analytical description is of the order of the experimental error for He and O and about 3 times the experimental error for N2 and thus provides a reasonable overall representation of the satellite observations. Two model schemes are used: one representing densities extrapolated to 450 km and one representing densities extrapolated to 120 km with exospheric temperatures inferred from N2 densities. Features in the thermospheric structure brought out by the model include a near 1000 hour local time maximum for He and a 1600 hour maximum for N2 at 450 km, a winter maximum in the O to N2 ratio at 120 km, and a 400°K summer to winter exospheric temperature difference with the diurnal temperature bulge located at high latitudes in summer.
- Publication:
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Journal of Geophysical Research
- Pub Date:
- 1974
- DOI:
- 10.1029/JA079i001p00215
- Bibcode:
- 1974JGR....79..215H
- Keywords:
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- Aeronomy: Composition (atomic or molecular)