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Ann. Geophys., 24, 2877-2889, 2006
www.ann-geophys.net/24/2877/2006/
© European Geosciences Union 2006
Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar
V. Deepa, G. Ramkumar, M. Antonita, K. K. Kumar, and M. N. Sasi
Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695022, India
Abstract. Tidal activity in the Mesospheric Lower Thermosphere (MLT) region over
Trivandrum (8.5° N, 77° E) is investigated using the observations from
newly installed SKiYMET Meteor Radar. The seasonal variability and vertical
propagation characteristics of atmospheric tides in the MLT region are
addressed in the present communication. The observations revealed that the
diurnal tide is more prominent than the semi/terdiurnal components over this
latitude. It is also observed that the amplitudes of meridional components
are stronger than that of zonal ones. The amplitude and phase structure
shows the vertical propagation of diurnal tides with vertical wavelength of
~25 km. However, the vertical wavelength of the semidiurnal tide showed
considerable variations. The vertical propagation characteristics of
the terdiurnal tide showed some indications of their generating mechanisms. The
observed features of tidal components are compared with Global Scale Wave
Model (GSWM02) values and they showed a similar amplitude and phase structure
for diurnal tides. Month-to-month variations in the tidal amplitudes have
shown significant seasonal variation. The observed seasonal variation is
discussed in light of the variation in tidal forcing and dissipation.
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