Forcing mechanisms of the 6 h tide in the mesosphere/lower thermosphere
<p>Solar tides such as the diurnal and semidiurnal tide, are forced in the lower and middle atmosphere through the diurnal cycle of solar radiation absorption. This is also the case with higher harmonics like the quarterdiurnal tide (QDT), but for these also non-linear interaction of tides...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | deu |
| Published: |
Copernicus Publications
2018-09-01
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| Series: | Advances in Radio Science |
| Online Access: | https://www.adv-radio-sci.net/16/141/2018/ars-16-141-2018.pdf |
| Summary: | <p>Solar tides such as the diurnal and semidiurnal tide, are
forced in the lower and middle atmosphere through the diurnal cycle of solar
radiation absorption. This is also the case with higher harmonics like the
quarterdiurnal tide (QDT), but for these also non-linear interaction of
tides such as the self-interaction of the semidiurnal tide, or the
interaction of terdiurnal and diurnal tides, are discussed as possible
forcing mechanism. To shed more light on the sources of the QDT, 12 years of
meteor radar data at Collm (51.3° N, 13° E) have been
analyzed with respect to the seasonal variability of the QDT at 82–97 km
altitude, and bispectral analysis has been applied. The results indicate
that non-linear interaction, in particular self-interaction of the
semidiurnal tide probably plays an important role in winter, but to a lesser
degree in summer. Numerical modelling of 6 h amplitudes qualitatively
reproduces the gross seasonal structure of the observed 6 h wave at Collm.
Model experiments with removed tidal forcing mechanisms lead to the
conclusion that, although non-linear tidal interaction is one source of the
QDT, the major forcing mechanism is direct solar forcing of the 6 h tidal
components.</p> |
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| ISSN: | 1684-9965 1684-9973 |