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Ann. Geophys., 20, 1877-1890, 2002
www.ann-geophys.net/20/1877/2002/
© European Geosciences Union 2002
Global distributions of diurnal and semi-diurnal tides: observations from HRDI-UARS of the MLT region
A. H. Manson, Y. Luo, and C. Meek
Institute of Space and Atmospheric Studies, University of Saskatchewan, SK, Canada
Correspondence to: A. H. Manson
(manson@dansas.usask.ca)
Abstract. HRDI (High Resolution
Doppler Interferometer-UARS) winds data have been analyzed in 4° latitude by
10° longitude cells at 96 km to obtain global contour maps of solar-tidal
amplitudes and phases, and also mean winds. The solstices June–July (1993),
December–January (1993–1994), and one equinox September–October (1994)
are shown.
The 24-h diurnal tide that maximizes near the 20–25°
latitude has significant seasonal changes with equinoctial maxima, and very
clear longitudinal variability. Maxima are very clear over the oceans. In
contrast, the 12-h semi-diurnal tides that maximize near the 40–55° latitude
have very strong seasonal changes with winter maxima, and more modest
longitudinal changes. The similarities with MLT (mesosphere-lower thermosphere)
radar observations (90 km) and the GSWM (Global Scale Wave Model) are very
satisfactory. The mean winds are consistent with expectations and show clear
poleward flow from summer to winter hemispheres in the solstices.
Key words. Meteorology and atmospheric dynamics
(middle atmosphere dynamics; waves and tides) Radio science (remote sensing)
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