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Day-to-day migrating and nonmigrating tidal variability due to the six-day planetary wave

Citation:Pedatella, N., H. Liu, and M.E. Hagan, 2012: Day-to-day migrating and nonmigrating tidal variability due to the six-day planetary wave. Journal of Geophysical Research-Space Physics, 117, A06301, DOI: 10.1029/2012JA017581.
UCAR Affiliations: Advanced Study Program (ASP), High Altitude Observatory (HAO), NCAR Directorate (NCARDIR)
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Abstract:To investigate day-to-day variability in the mesosphere and lower thermosphere (MLT), an idealized simulation of a six-day westward propagating zonal wave number-1 planetary wave is performed using the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM). The six-day planetary wave introduces a six-day periodicity in the zonal mean atmosphere, migrating and nonmigrating tides, as well as in secondary waves that are produced by nonlinear planetary wave-tide interactions. We have further used the linear Global Scale Wave Model (GSWM) to isolate the effect of how the day-to-day changes in zonal mean zonal winds may influence tides in the MLT. The most significant changes are observed in the migrating diurnal tide (DW1), eastward propagating nonmigrating tides with zonal wave numbers-2 and -3 (DE2 and DE3), and a 20 hr eastward propagating wave with zonal wave number-2 (20E2). Because we have included the lower atmospheric source of nonmigrating tides, DE2 and DE3 are present with relatively large amplitudes in the MLT, even in the absence of planetary wave forcing. The 20E2 wave is produced by the nonlinear interaction between the DE3 and the six-day planetary wave, and its large amplitude indicates the importance of including the realistic spectra of nonmigrating tides in numerical simulations of planetary waves. The GSWM simulations reveal that the DW1 is not significantly influenced by the changes in the zonal mean winds. View More
Resource Type:Article
Date Published
Published Version:10.1029/2012JA017581
Copyright Notice:Copyright 2012 American Geophysical Union.
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