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Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 180729 bytes)
GEOPHYSICAL RESEARCH LETTERS,
VOL. 31,
L11111,
doi:10.1029/2004GL019624,
2004
Tidal modulation of the gravity-wave momentum flux in the Antarctic mesosphere
P. J. Espy
British Antarctic Survey, Cambridge, UK
G. O. L. Jones
British Antarctic Survey, Cambridge, UK
G. R. Swenson
University of Illinois, Urbana, Illinois, USA
J. Tang
University of Illinois, Urbana, Illinois, USA
M. J. Taylor
Utah State University, Logan, Utah, USA
Abstract
Airglow imager and dynasonde/IDI radar wind measurements at Halley Station, Antarctica (76°S, 27°W) have been used to estimate
the diurnal variation of the vertical fluxes of horizontal momentum carried by high-frequency atmospheric gravity waves. The
cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from the sodium airglow
imager data collected during four consecutive nights of near total darkness during July of 2000. These were combined with
wind-velocity variances from coincident radar measurements to estimate the upper limit of the vertical flux of horizontal
momentum during three-hour intervals throughout the period. The resulting momentum flux showed a marked semi-diurnal oscillation
in the zonal and meridional components. Calculations of the momentum flux through the Na airglow show variations in period
and phase consistent with the observations, implying that tidal propagation and modulated gravity-wave forcing may both affect
observed wind variations.
Received 2
February
2004;
accepted 13
May
2004;
published 12
June
2004.
Index Terms: 3332 Meteorology and Atmospheric Dynamics: Mesospheric dynamics; 3334 Meteorology and Atmospheric Dynamics: Middle atmosphere dynamics (0341, 0342); 3384 Meteorology and Atmospheric Dynamics: Waves and tides.
Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 180729 bytes)
Citation: Espy, P. J., G. O. L. Jones, G. R. Swenson, J. Tang, and M. J. Taylor
(2004),
Tidal modulation of the gravity-wave momentum flux in the Antarctic mesosphere,
Geophys. Res. Lett.,
31,
L11111,
doi:10.1029/2004GL019624.
Copyright 2004 by the American Geophysical Union.
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