This paper constructs and analyzes a reduced nonlinear stochastic model of extratropical low-frequency variability. To do so, it applies multilevel quadratic regression to the output of a long simulation of a global baroclinic, quasigeostrophic, three-level (QG3) model with topography; the model's phase space has a dimension of O(104). The reduced model has 45 variables and captures well the non-Gaussian features of the QG3 model's probability density function (PDF). In particular, the reduced model's PDF shares with the QG3 model its four anomalously persistent flow patterns, which correspond to opposite phases of the Arctic Oscillation and the North Atlantic Oscillation, as well as the Markov chain of transitions between these regimes. In addition, multichannel singular spectrum analysis identifies intraseasonal oscillations with a period of 35–37 days and of 20 days in the data generated by both the QG3 model and its low-dimensional analog. An analytical and numerical study of the reduced model starts with the fixed points and oscillatory eigenmodes of the model's deterministic part and uses systematically an increasing noise parameter to connect these with the behavior of the full, stochastically forced model version. The results of this study point to the origin of the QG3 model's multiple regimes and intraseasonal oscillations and identify the connections between the two types of behavior.
Statistical methods
Empirical mode reduction in a model of extratropical low-frequency variability. Journal of the Atmospheric Sciences. 2006;63 (7) :1859–1877.Abstract
.
The Role of Oscillatory Modes in U.S. Business Cycles. Fondazione Eni Enrico Mattei (FEEM) [Internet]. 2012;26 :1. Publisher's VersionAbstract
.
Predicting weather regime transitions in Northern Hemisphere datasets. Climate Dynamics. 2007;29 (5) :535–551.
.
Oscillatory Climate Modes in the Eastern Mediterranean and Their Synchronization with the North Atlantic Oscillation. Journal of Climate. 2010;23 (15) :4060–4079.Abstract
.
Gap Filling of Solar Wind Data by Singular Spectrum Analysis. Geophysical Research Letters. 2010;37 :L15101.Abstract
.
Reduced models of atmospheric low-frequency variability: Parameter estimation and comparative performance. Physica D: Nonlinear Phenomena. 2010;239 (3) :145–166.Abstract
.
Quasi-quadrennial and quasi-biennial variability in the equatorial Pacific. Climate Dynamics. 1995;12 :101–112.Abstract
.
Cluster analysis of typhoon tracks. Part II: Large-scale circulation and ENSO. Journal of Climate. 2007;20 (14) :3654–3676.
.
Interdecadal oscillations and the warming trend in global temperature time series. Nature. 1991;350 (6316) :324–327.Abstract
.
Singular spectrum analysis in nonlinear dynamics, with applications to paleoclimatic time series. Physica D. 1989;35 (3) :395–424.Abstract
.
Low-order stochastic model and ``past-noise forecasting" of the Madden-Julian oscillation. Geophysical Research Letters. 2013;40 :5305–5310.
.
Oscillatory modes of extended Nile River records (A.D. 622–1922). Geophysical Research Letters. 2005;32 (10) :L10702.Abstract
.
Trends, interdecadal and interannual oscillations in global sea-surface temperatures. Climate Dynamics. 1998;14 (7) :545–569.Abstract
.
Probabilistic clustering of extratropical cyclones using regression mixture models. Climate Dynamics. 2007;29 (4) :423–440.
.
Impacts of natural disasters on a dynamic economy. In: Extreme Events : Observations, Modeling, and Economics. American Geophysical Union and Wiley-Blackwell ; 2015. pp. 343–360.Abstract
.