 |
| Titel |
Aura MLS observations of the westward-propagating s=1, 16-day planetary wave in the stratosphere, mesosphere and lower thermosphere |
| VerfasserIn |
K. A. Day, R. E. Hibbins, N. J. Mitchell |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 9 ; Nr. 11, no. 9 (2011-05-05), S.4149-4161 |
| Datensatznummer |
250009695
|
| Publikation (Nr.) |
 copernicus.org/acp-11-4149-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Microwave Limb Sounder (MLS) on the Aura satellite has been used to
measure temperatures in the stratosphere, mesosphere and lower thermosphere.
The data used here are from August 2004 to December 2010 and latitudes
75° N to 75° S. The temperature data reveal the regular presence
of a westward-propagating 16-day planetary wave with zonal wavenumber 1. The
wave amplitudes maximise in winter at middle to high latitudes, where
monthly-mean amplitudes can be as large as ~8 K. Significant wave
amplitudes are also observed in the summer-time mesosphere and lower
thermosphere (MLT) and at lower stratospheric heights of up to ~20 km
at middle to high latitudes. Wave amplitudes in the Northern Hemisphere
approach values twice as large as those in the Southern Hemisphere. Wave
amplitudes are also closely related to mean zonal winds and are largest in
regions of strongest eastward flow. There is a reduction in wave amplitudes
at the stratopause. No significant wave amplitudes are observed near the
equator or in the strongly westward background winds of the atmosphere in
summer. This behaviour is interpreted as a consequence of wave/mean-flow
interactions. Perturbations in wave amplitude summer MLT are compared to
those simultaneously observed in the winter stratosphere of the opposite
hemisphere and found to have a correlation coefficient of +0.22, suggesting
a small degrees of inter-hemispheric coupling. We interpret this to mean that
some of the summer-time MLT wave may originate in the winter stratosphere of
the opposite hemisphere and have been ducted across the equator. We do not
observe a significant QBO modulation of the 16-day wave amplitude in the
polar summer-time MLT. Wave amplitudes were also observed to be suppressed
during the major sudden stratospheric warming events of the Northern
Hemisphere winters of 2006 and 2009. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|