TY - JOUR
A1 - Malik, Nishant
A1 - Bookhagen, Bodo
A1 - Marwan, Norbert
A1 - Kurths, Jürgen
T1 - Analysis of spatial and temporal extreme monsoonal rainfall over South Asia using complex networks
JF - Climate dynamics : observational, theoretical and computational research on the climate system
N2 - We present a detailed analysis of summer monsoon rainfall over the Indian peninsular using nonlinear spatial correlations. This analysis is carried out employing the tools of complex networks and a measure of nonlinear correlation for point processes such as rainfall, called event synchronization. This study provides valuable insights into the spatial organization, scales, and structure of the 90th and 94th percentile rainfall events during the Indian summer monsoon (June-September). We furthermore analyse the influence of different critical synoptic atmospheric systems and the impact of the steep Himalayan topography on rainfall patterns. The presented method not only helps us in visualising the structure of the extreme-event rainfall fields, but also identifies the water vapor pathways and decadal-scale moisture sinks over the region. Furthermore a simple scheme based on complex networks is presented to decipher the spatial intricacies and temporal evolution of monsoonal rainfall patterns over the last 6 decades.
KW - Indian summer monsoon
KW - Event synchronization
KW - Complex networks
KW - Rainfall patterns
Y1 - 2012
U6 - http://dx.doi.org/10.1007/s00382-011-1156-4
SN - 0930-7575 (print)
VL - 39
IS - 3-4
SP - 971
EP - 987
PB - Springer
CY - New York
ER -
TY - JOUR
A1 - Thiel, Marco
A1 - Romano, Maria Carmen
A1 - Kurths, Jürgen
A1 - Rolfs, Martin
A1 - Kliegl, Reinhold
T1 - Generating surrogates from recurrences
N2 - In this paper, we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i.e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be only one centre in the brain that produces the fixational movements in both eyes or a close link between the two centres.
Y1 - 2008
UR - http://rsta.royalsocietypublishing.org/
SN - 1364-503X
ER -
TY - JOUR
A1 - Baptista, Murilo S.
A1 - Pereira, Tiago
A1 - Sartorelli, J. C.
A1 - Caldas, I. L.
A1 - Kurths, Jürgen
T1 - Non-transitive maps in phase synchronization
N2 - Concepts from Ergodic Theory are used to describe the existence of special non-transitive maps in attractors of phase synchronous chaotic oscillators. In particular, it is shown that, for a class of phase-coherent oscillators, these special maps imply phase synchronization. We illustrate these ideas in the sinusoidally forced Chua's circuit and two coupled Rossler oscillators. Furthermore, these results are extended to other coupled chaotic systems. In addition, a phase for a chaotic attractor is defined from the tangent vector of the flow. Finally, it is discussed how these maps can be used for the real-time detection of phase synchronization in experimental systems. (c) 2005 Elsevier B.V. All rights reserved
Y1 - 2005
ER -
TY - JOUR
A1 - Landa, Polina S.
A1 - Zaikin, Alexei A.
A1 - Ushakov, V. G.
A1 - Kurths, Jürgen
T1 - Influence of additive noise on transitions in nonlinear systems
N2 - The effect of additive noise on transitions in nonlinear systems far from equilibrium is studied. It is shown that additive noise in itself can induce a hidden phase transition, which is similar to the transition induced by multiplicative noise in a nonlinear oscillator [P. Landa and A. Zaikin, Phys. Rev. E 54, 3535 (1996)]. Investigation of different nonlinear models that demonstrate phase transitions induced by multiplicative noise shows that the influence of additive noise upon such phase transitions can be crucial: additive noise can either blur such a transition or stabilize noise-induced oscillations.
Y1 - 2000
UR - http://link.aps.org/abstract/PRE/v61/p4809
ER -
TY - JOUR
A1 - Zaks, Michael A.
A1 - Pikovskij, Arkadij S.
A1 - Kurths, Jürgen
T1 - On the generalized dimensions for the fourier spectrum of the thue-morse sequence
Y1 - 1999
ER -
TY - JOUR
A1 - Gowin, W.
A1 - Saparin, Peter
A1 - Kurths, Jürgen
A1 - Felsenberg, D.
T1 - Bone Architecture assessment with Measures of Complexity
Y1 - 2001
ER -
TY - JOUR
A1 - Feudel, Fred
A1 - Witt, Annette
A1 - Gellert, Marcus
A1 - Kurths, Jürgen
A1 - Grebogi, Celso
A1 - Sanjuan, Miguel Angel Fernandez
T1 - Intersections of stable and unstable manifolds : the skeleton of Lagrangian chaos
N2 - We study Hamiltonian chaos generated by the dynamics of passive tracers moving in a two-dimensional fluid flow and describe the complex structure formed in a chaotic layer that separates a vortex region from the shear flow. The stable and unstable manifolds of unstable periodic orbits are computed. It is shown that their intersections in the Poincare map as an invariant set of homoclinic points constitute the backbone of the chaotic layer. Special attention is paid to the finite time properties of the chaotic layer. In particular, finite time Lyapunov exponents are computed and a scaling law of the variance of their distribution is derived. Additionally, the box counting dimension as an effective dimension to characterize the fractal properties of the layer is estimated for different duration times of simulation. Its behavior in the asymptotic time limit is discussed. By computing the Lyapunov exponents and by applying methods of symbolic dynamics, the formation of the layer as a function of the external forcing strength, which in turn represents the perturbation of the originally integrable system, is characterized. In particular, it is shown that the capture of KAM tori by the layer has a remarkable influence on the averaged Lyapunov exponents. (C) 2004 Elsevier Ltd. All rights reserved
Y1 - 2005
ER -
TY - JOUR
A1 - Sitz, Andre
A1 - Schwarz, Udo
A1 - Kurths, Jürgen
A1 - Voss, Henning U.
T1 - Estimation of parameters and unobserved components for nonlinear systems from noisy time series
N2 - We study the problem of simultaneous estimation of parameters and unobserved states from noisy data of nonlinear time-continuous systems, including the case of additive stochastic forcing. We propose a solution by adapting the recently developed statistical method of unscented Kalman filtering to this problem. Due to its recursive and derivative-free structure, this method minimizes the cost function in a computationally efficient and robust way. It is found that parameters as well as unobserved components can be estimated with high accuracy, including confidence bands, from heavily noise-corrupted data.
Y1 - 2002
UR - http://pre.aps.org/
ER -
TY - JOUR
A1 - Spahn, Frank
A1 - Schwarz, Udo
A1 - Kurths, Jürgen
T1 - Clustering of granular assemblies with temperature dependent restitution under Keplerian differential rotation
Y1 - 1997
ER -
TY - JOUR
A1 - Schwache, A.
A1 - Kurths, Jürgen
A1 - Mitschke, F.
A1 - Voss, Henning U.
T1 - Equations of motion from chaotic data : a driven optical fiber ring resonator
Y1 - 1999
ER -