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A numerical model of nonmigrating diurnal tides between the surface and 65 kmObservations of surface pressure and middle atmosphere temperatures and winds indicate that a substantial nonmigrating component is present in the diurnal tide. The nonmigrating tides, which propagate with a zonal phase speed that is different from the earth's rotation, are attributed to the diurnal heating of geographically fixed sources. In this study we utilize a classical tidal model to examine the propagation characteristics of diurnal tides. The global fields of tropospheric sensible, radiative, and latent heating used to drive the model are supplied from summer and winter diurnal climatologies of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM2). A novel aspect of this study is the focus on the relative importance of the nonmigrating components. The classical model successfully reproduces many observed features of the low-latitude diurnal surface pressure tides. In the middle atmosphere, the simulated migrating (or sun-synchronous) tide shows qualitative agreement with November-March Limb Infrared Monitor of the Stratosphere (LIMS) observations. Tropospheric solar heating is clearly the dominant driving force for the migrating tide, with secondary contributions from boundary-layer sensible heating and tropospheric latent heat release. The leading modes of the zonal mean tide are also driven chiefly by tropospheric solar heating. The higher-order modes of the zonal mean and eastward propagating tides may be attributed to the joint effects of tropospheric solar heating, sensible heating, and latent heat release. The LIMS and other data reveal features that cannot be explained or examined within the context of the classical model used in the present study. These include upward phase propagation, vertical attenuation, and temporal variations in the migrating diurnal tide.
Document ID
19950048128
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Lieberman, Ruth S.
(Univ. of Washington, Seattle, WA United States)
Leovy, Conway B.
(Univ. of Washington, Seattle, WA United States)
Date Acquired
August 16, 2013
Publication Date
February 15, 1995
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 52
Issue: 4
ISSN: 0022-4928
Subject Category
Meteorology And Climatology
Accession Number
95A79727
Funding Number(s)
CONTRACT_GRANT: NAS5-26301
CONTRACT_GRANT: NAGW-471
Distribution Limits
Public
Copyright
Other

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