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Ann. Geophys., 23, 305-323, 2005
www.ann-geophys.net/23/305/2005/
© European Geosciences Union 2005
Wave activity (planetary, tidal) throughout the middle atmosphere (20-100km) over the CUJO network: Satellite (TOMS) and Medium Frequency (MF) radar observations
A. H. Manson1, C. E. Meek1, T. Chshyolkova1, S. K. Avery2, D. Thorsen3, J. W. MacDougall4, W. Hocking4, Y. Murayama5, and K. Igarashi5
1Institute of Space and Atmospheric Studies, University of Saskatchewan, 116 Science Place, Saskatoon, SK, S7N 5E2, Canada
2CIRES, University of Colorado, Boulder, USA
3Department of Electrical and Computer Engineering, University of Alaska, Fairbanks, USA
4Department of Physics and Astronomy, University of Western Ontario, London, Canada
5National Institute of Information and Communications Technology, Tokyo, Japan
Abstract. Planetary and tidal wave activity in the tropopause-lower stratosphere and
mesosphere-lower thermosphere (MLT) is studied using combinations of
ground-based (GB) and satellite instruments (2000-2002). The relatively new MFR
(medium frequency radar) at Platteville (40° N, 105° W) has provided
the opportunity to create an operational network of middle-latitude MFRs,
stretching from 81° W-142° E, which provides winds and tides 70-100km.
CUJO (Canada U.S. Japan Opportunity) comprises systems at London (43° N,
81° W), Platteville (40° N, 105° W),
Saskatoon (52° N, 107° W), Wakkanai (45° N, 142° E) and Yamagawa (31° N, 131° E). It
offers a significant 7000-km longitudinal sector in the North
American-Pacific region, and a useful range of latitudes (12-14°) at two
longitudes. Satellite data mainly involve the daily values of the total
ozone column measured by the Earth Probe (EP) TOMS (Total Ozone Mapping
Spectrometer) and provide a measure of tropopause-lower stratospheric
planetary wave activity, as well as ozone variability.
Climatologies of ozone and winds/tides involving frequency versus time
(wavelet) contour plots for periods from 2-d to 30-d and the interval from
mid 2000 to 2002, show that the changes with altitude, longitude and
latitude are very significant and distinctive. Geometric-mean wavelets for
the region of the 40° N MFRs demonstrate occasions during the autumn,
winter and spring months when there are similarities in the spectral
features of the lower atmosphere and at mesopause (85km) heights. Both
direct planetary wave (PW) propagation into the MLT, nonlinear PW-tide
interactions, and disturbances in MLT tides associated with fluctuations in
the ozone forcing are considered to be possible coupling processes. The
complex horizontal wave numbers of the longer period oscillations are
provided in frequency contour plots for the TOMS satellite data to
demonstrate the differences between lower atmospheric and MLT wave motions
and their directions of propagation.
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