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| Titel |
Characteristics of atmospheric Kelvin waves during warm and cold ENSO phases observed with GPS RO |
| VerfasserIn |
Barbara Scherllin-Pirscher, Florian Ladstädter, Andrea Steiner, Gottfried Kirchengast |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110372
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| Publikation (Nr.) |
 EGU/EGU2015-10367.pdf |
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| Zusammenfassung |
| Inter-annual variability in the Earth’s troposphere at low and middle latitudes is dominated by
the El Niño–Southern Oscillation (ENSO) phenomenon. While ENSO emerges from an
atmosphere-ocean interaction in the tropical Pacific, it has a significant impact on global
weather and climate. Atmospheric wave dynamics plays a crucial role in this context.
However, current understanding of this wave dynamics is mostly based on climate model
output and reanalysis data.
We use observational data from Global Positioning System (GPS) radio occultation (RO)
measurements to investigate characteristics of atmospheric Kelvin waves during warm and
cold ENSO phases. Due to their high accuracy and vertical resolution, RO data provide
reliable and valuable information on wave-induced temperature oscillations with short
vertical wavelengths of a few kilometers.
After the launch of the six micro-satellites of the Formosat-3/COSMIC mission in April
2006, the number of RO measurements per day increased significantly compared to earlier
time periods. With an appropriate binning strategy, the sampling is therefore sufficiently
dense from mid-2006 onwards in order to capture the main characteristics of large-scale
atmospheric waves. Frequencies and wavelengths of atmospheric Kelvin waves are extracted
from space-time spectral analysis for overlapping 60-day time series centered on each
month.
In this study we focus on the northern hemisphere winter season DJF (December,
January, February) using data from DJF 2006/07 to DJF 2011/12. Comparative results
are presented for warm ENSO phases, which occurred in DJF 2006/07 and DJF
2009/10, and for cold ENSO phases in DJF 2007/08, DJF 2010/11, and DJF 2011/12. |
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