|
|
 |
|
|
Ann. Geophys., 24, 453-465, 2006
www.ann-geophys.net/24/453/2006/
© European Geosciences Union 2006
Tidal signatures in mesospheric turbulence
C. M. Hall1, S. Nozawa2, A. H. Manson3, and C. E. Meek3
1Tromsø Geophysical Observatory, University of Tromsø, 9037 Tromsø, Norway
2STELab Nagoya University, Chikusa-ku Nagoya 464-01, Japan
3Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
Abstract. We search for the presence of tidal signatures in high
latitude mesospheric turbulence as parameterized by turbulent energy
dissipation rate estimated using a medium frequency radar, quantifying our
findings with the aid of correlation analyses. A diurnal periodicity is not
particularly evident during the winter and spring months but is a striking
feature of the summer mesopause. While semidiurnal variation is present to
some degree all year round, it is particularly pronounced in winter. We find
that the maximum in the summer 24-h variation corresponds to that of the
westward phase of the diurnal tide, and that the maximum in the winter 12 h
variation corresponds to that of the southward phase of the semidiurnal
tide. This information is used to infer the horizontal propagation direction
of gravity waves: during the summer the eastward direction is consistent
with closure of the summer vortex, while in winter the inferred directions
require more complex arguments.
Full Article in PDF (702 KB) |
|
|
