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| Titel |
QBO and ENSO indices from GPS Radio Occultation to describe atmospheric variability |
| VerfasserIn |
Hallgeir Wilhelmsen, Barbara Scherllin-Pirscher, Florian Ladstädter, Andrea K. Steiner |
| 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 |
250144453
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| Publikation (Nr.) |
 EGU/EGU2017-8279.pdf |
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| Zusammenfassung |
| The GPS Radio Occultation (RO) satellite technique provides 15 years (since 2001)
of high quality measurements with global coverage and high vertical resolution.
These properties make RO a valuable dataset for the characterization of atmospheric
variability.
Atmospheric variability arises from different physical processes and manifests itself on
different time-scales. In this study, we focus on inter-annual atmospheric variability of the
tropical troposphere and stratosphere, which mainly results from El Niño-Southern
Oscillation (ENSO) and the Quasi Biennial Oscillation (QBO). To describe these modes of
variability proxies (so called indices) are used.
The ENSO index is commonly computed from tropical sea surface temperature
anomalies. For describing the QBO, usually wind speeds at the 30 hPa and/or 50 hPa levels
are used. However, both atmospheric variability patterns change with height. Thus, when
computing, e.g., height-resolved trends, it is essential to account for these height-varying
variability patterns in order to properly remove their contributions.
We perform a principle component analysis of the RO temperature record from 2001 to
2016 to identify dominating variability modes. Then we use these principal component time
series to provide vertically high resolved QBO and ENSO indices based on temperatures
from RO. |
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