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Mesospheric Non-Migrating Tides Generated With Planetary WavesWe discuss results from a modeling study with our Numerical Spectral Model (NSM) that specifically deals with the non-migrating tides generated in the mesosphere. The NSM extends from the ground to the thermosphere, incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GWs), and it describes the major dynamical features of the atmosphere including the wave driven equatorial oscillations (QBO and SAO), and the seasonal variations of tides and planetary waves. Accounting solely for the excitation sources of the solar migrating tides, the NSM generates through dynamical interactions also non-migrating tides in the mesosphere that are comparable in magnitude to those observed. Large non-migrating tides are produced in the diurnal and semi-diurnal oscillations for the zonal mean (m = 0) and in the semidiurnal oscillation for m = 1. In general, significant eastward and westward propagating tides are generated for all the zonal wave numbers m = 1 to 4. To identify the cause, the NSM is run without the solar heating for the zonal mean (m = 0), and the amplitudes of the resulting non-migrating tides are then negligibly small. In this case, the planetary waves are artificially suppressed, which are generated in the NSM through instabilities. This leads to the conclusion that the non-migrating tides are generated through non-linear interactions between planetary waves and migrating tides, as Forbes et al. and Talaat and Liberman had proposed. In an accompanying paper, we present results from numerical experiments, which indicate that gravity wave filtering contributes significantly to produce the non-linear coupling that is involved.
Document ID
20030102152
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Mayr, H. G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mengel, J. G. (Science Systems and Applications, Inc. Lanham, MD, United States)
Talaat, E. L. (Johns Hopkins Univ. Laurel, MD, United States)
Porter, H. S. (Furman Univ. Greenville, SC, United States)
Chan, K. L. (Hong Kong Univ. of Science and Technology Kowloon, Hong Kong)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Public Use Permitted.

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