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| Titel |
A Hidden Markov Model Perspective on Regimes in Atmospheric Flows |
| VerfasserIn |
Christian Franzke |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048210
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| Zusammenfassung |
| A controversial topic in the recent climate modeling literature is the fashion in which persistent circulation regimes in the atmosphere occur despite nearly Gaussian statistics of the large-scale planetary waves. In my presentation I will introduce a hierarchy of circulation models and examine their regime behavior through hidden Markov model (HMM) analysis of the time series of suitable low-frequency planetary waves. This analysis elucidates how statistically significant regime transitions occur despite nearly Gaussian behavior in the associated probability distribution function and without a significant role for the low-order truncated nonlinear dynamics alone. I will show that in a batrotropic model the turbulent backscatter onto a three-dimensional subspace of low-frequency modes is responsible for these effects and not fixed points of the corresponding truncated low-order system. Furthermore, I will discuss the predictability of regime transitions and the interannual variability of the frequency of occurence of circulation regimes in reanalysis data. |
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