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| Titel |
Multivariate statistical data analysis methods for detecting baroclinic wave interactions in the thermally driven rotating annulus |
| VerfasserIn |
Thomas von Larcher, Uwe Harlander, Kiril Alexandrov, Yongtai Wang |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250045302
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| Zusammenfassung |
| Experiments on baroclinic wave instabilities in a rotating cylindrical gap have been long
performed, e.g., to unhide regular waves of different zonal wave number, to better understand
the transition to the quasi-chaotic regime, and to reveal the underlying dynamical processes
of complex wave flows.
We present the application of appropriate multivariate data analysis methods on time
series data sets acquired by the use of non-intrusive measurement techniques of a quite
different nature. While the high accurate Laser-Doppler-Velocimetry (LDV ) is
used for measurements of the radial velocity component at equidistant azimuthal
positions, a high sensitive thermographic camera measures the surface temperature
field.
The measurements are performed at particular parameter points, where our former studies
show that kinds of complex wave patterns occur [1, 2]. Obviously, the temperature data set
has much more information content as the velocity data set due to the particular measurement
techniques.
Both sets of time series data are analyzed by using multivariate statistical techniques.
While the LDV data sets are studied by applying the Multi-Channel Singular Spectrum
Analysis (M - SSA), the temperature data sets are analyzed by applying the Empirical
Orthogonal Functions (EOF ).
Our goal is (a) to verify the results yielded with the analysis of the velocity data and (b)
to compare the data analysis methods. Therefor, the temperature data are processed in a way
to become comparable to the LDV data, i.e. reducing the size of the data set in such a
manner that the temperature measurements would imaginary be performed at equidistant
azimuthal positions only. This approach initially results in a great loss of information. But
applying the M - SSA to the reduced temperature data sets enable us to compare the
methods.
[1] Th. von Larcher and C. Egbers, Experiments on transitions of baroclinic waves in a
differentially heated rotating annulus, Nonlinear Processes in Geophysics, 2005, 12,
1033-1041, NPG Print: ISSN 1023-5809, NPG Online: ISSN 1607-7946
[2] U. Harlander, Th. von Larcher, Y. Wang and C. Egbers, PIV- and LDV-measurements of
baroclinic wave interactions in a thermally driven rotating annulus, Experiments in Fluids,
2009, DOI: 10.1007/s00348-009-0792-5 |
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