The wind in the lower thermosphere is generally considered to be composed of prevailing, tidal, and gravity wave components, but observational data are too scanty and heterogeneous to enable specification of the contribution of each component. This paper computes the tidal winds from theory, adding to the existing theory of atmospheric solar tides the effects of heat conductivity and the absorption of solar radiation in the thermosphere. Comparison of the theoretical results with observations indicates that major features of the vapor trail drifts --such as the wind speed maximum near 105 km altitude, the velocity oscillations below it, and the quiescent region above --can be explained in terms of interference between tidal modes propagating in an atmosphere with dissipation. Results also indicate that variations in water vapor excitation may be a source of the day-to-day changes observed in the Sq current system. (See also R-585.) 16 pp. Ref.
This report is part of the RAND Corporation Paper series. The paper was a product of the RAND Corporation from 1948 to 2003 that captured speeches, memorials, and derivative research, usually prepared on authors' own time and meant to be the scholarly or scientific contribution of individual authors to their professional fields. Papers were less formal than reports and did not require rigorous peer review.
This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit www.rand.org/pubs/permissions.
The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.