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| Titel |
Does strong tropospheric forcing cause large amplitude mesospheric gravity waves? A Deepwave Case Study |
| VerfasserIn |
Martina Bramberger, Andreas Dörnbrack, Benedikt Ehard, Bernd Kaifler, Natalie Kaifler, Stephan Rahm, Benjamin Witschas, Markus Rapp, Simon Vosper, Andrew Orr, Bifford P. Williams, David C. Fritts, P.-Dominique Pautet, Michael J. Taylor, Christian Mallaun |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250148281
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| Publikation (Nr.) |
 EGU/EGU2017-12524.pdf |
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| Zusammenfassung |
| On 4 July 2014, during the Deep Propagating Gravity Wave Experiment (DEEPWAVE),
strong horizontal winds up to 35 ms−1 caused the excitation of gravity waves containing the
largest energy fluxes of the complete campaign (38 W m−2). At the same time, large
amplitude mesospheric gravity waves were detected by the Temperature Lidar for Middle
Atmospheric Research (TELMA) located in Lauder (45.0∘ S, 169.7∘ E). This combination
lead to the question whether the observed mesospheric gravity waves are generated by the
tropospheric forcing.
For our study we use an extensive data set which comprises TELMA data, in situ
measurements of the two aircraft, radiosondes, wind lidar measurements aboard DLR Falcon
as well as Rayleigh lidar and advanced mesospheric temperature mapper (AMTM)
measurements aboard the NSF/NCAR GV. To complement the measurements, studies with
limited area simulations of the Unified Model are taken into account. This unique data set
allows for the observation of the evolution of the gravity waves from the troposphere to the
mesosphere.
Our investigations revealed a complicated situation where the propagation of mountain waves
is influenced by partial reflection at the tropopause, a valve layer in the lower stratosphere
filtering a part of the wave spectrum and possibly partial reflection at the polar night jet.
Nevertheless stationary waves are found in the AMTM measurements with horizontal
wavelengths between 30 and 130 km. Although the measurements comprised all altitudes
from the troposphere to the mesosphere, still numerical studies proved to be a valuable asset
in order to answer the question raised. |
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