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Detailed Reference Information |
Sivjee, G.G. and Walterscheid, R.L. (2002). Low-frequency intraseasonal variations of the wintertime very high latitude mesopause regions. Journal of Geophysical Research 107: doi: 10.1029/2001JA000164. issn: 0148-0227. |
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We have performed a spectral analysis of three fall and winter airglow data sets each for South Pole Station and for Eureka, Canada (80¿N). These analyses show significant spectral features in the mesopause region at very high latitudes that are similar in period to low-frequency intraseasonal (IS) variations seen in analysis of length of day, atmospheric angular momentum variations, and outgoing long wave radiation, as well as in height or wind fields up to 10 hPa (~32 km). These are fairly broadband spectral features centered approximately at 17, 23, and 45 days. The 17-day oscillation we find is more prominent than that found in the data sets reflecting variations mainly in the troposphere and stratosphere. This oscillation is most likely associated with the second symmetric s = 1 free Rossby mode. The data from South Pole Station should not reflect this mode, as such, because the spectral components that produce airglow variations should vanish at the pole unless they are zonally symmetric; however, free oscillations having zonal wave number zero with such long periods should not exist. We suggest that, at least at South Pole Station, the 17-day oscillation is driven by interactions between the global Rossby mode and stationary wave number one planetary waves. In addition to the low-frequency oscillations that have been reported in the IS literature, we see a wave in the 12--14 day period range. At South Pole Station that wave may also reflect forcing by a global free mode. |
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Abstract |
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Keywords
Meteorology and Atmospheric Dynamics, Middle atmosphere dynamics (0341, 0342), Atmospheric Composition and Structure, Middle atmosphere--energy deposition, Atmospheric Composition and Structure, Airglow and aurora, Meteorology and Atmospheric Dynamics, Remote sensing |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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