Quasi-Biennial Oscillations extracted from the monthly NAO index and temperature records are phase-synchronized

Milan Palus
Institute of Computer Science, Academy of Sciences of the Czech Republic
Pod vodárenskou vezí 2, 182 07 Prague 8, Czech Republic
E-mail: mp@cs.cas.cz

Dagmar Novotna
Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic
Bocni II/1401, 141 31 Prague 4, Czech Republic
E-mail: nov@ufa.cas.cz

Abstract:

Using the extension of the Monte Carlo Singular System Analysis (MC SSA), based on evaluating and testing regularity of dynamics of the SSA modes against the colored noise null hypothesis, we demonstrate detection of oscillatory modes with period about 27 months in records of monthly average near-surface air temperature from several European locations, as well as in the monthly North Atlantic Oscillation index. According to their period, the detected modes can be attributed to the quasi-biennial oscillations (QBO). The QBO modes extracted from the temperature and from the NAO index underwent the synchronization analysis and their phase synchronization has been confirmed with high statistical significance.