Long-term changes and trends of mesosphere/lower thermosphere gravity waves over Collm, Germany
<p>Time series of mesosphere/lower thermosphere half-hourly winds over Collm (51.3° N, 13.0° E) have been obtained from 1984–2007 by low frequency (LF) spaced receiver measurements and from 2004 to date by very high frequency (VHF) meteor radar Doppler wind observations in the height range 82–...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | deu |
| Published: |
Copernicus Publications
2025-05-01
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| Series: | Advances in Radio Science |
| Online Access: | https://ars.copernicus.org/articles/23/21/2025/ars-23-21-2025.pdf |
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| Summary: | <p>Time series of mesosphere/lower thermosphere half-hourly winds over Collm (51.3° N, 13.0° E) have been obtained from 1984–2007 by low frequency (LF) spaced receiver measurements and from 2004 to date by very high frequency (VHF) meteor radar Doppler wind observations in the height range 82–97 km. These observations are analysed with respect to gravity wave (GW) climatology and trends. From half-hourly differences of zonal and meridional winds, GW variance proxies have been calculated that describe amplitude variations in the period range 1–3 h. After applying corrections to account for instrumental differences, the GW climatology and time series have been obtained. The mean GW activity in the upper mesosphere shows maximum amplitudes in summer, while in the lower thermosphere GWs maximize in winter. At altitudes around 90 km, positive/negative long-term trends are visible in winter/summer, consistent with increasing/decreasing mesospheric winds. In the lower thermosphere, however, long-term amplitude trends are generally positive. We notice qualitative correspondence of these trends with those derived from satellite observations of potential energy despite of different wavelength ranges seen by radar and satellite. Quasi-decadal and interannual variations of GW amplitudes and mean winds are also visible, showing a possible influence of the 11-year solar cycle or lower atmosphere circulation patterns.</p> |
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| ISSN: | 1684-9965 1684-9973 |