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Climate Model Attractors: Chaos, Quasi-regularity and Sensitivity ...

By: A. S. Gritsoun; V. P. Dymnikov

Description: Institute of Numerical Mathematics, Moscow, Russia. In this paper we discuss some theoretical results obtained for climate models (theorems for the existence of global attractors and inertial manifolds, estimates of attractor dimension and Lyapunov exponents, symmetry property of Lyapunov spectrum). We define the conditions for "quasi-regular behaviour" of a climate system. Under these conditions, the system behaviour is subject to th...

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On the Nonstationarity of the Decadal Periodicities of the Length ...

By: G. Consolini; R. Tozzi; P. De Michelis

Description: Istituto Nazionale di Geofisica e Vulcanologia, 00143 Rome, Italy. The Earth's rotation rate is not constant, but changes on all observable timescales, from subdaily to decadal and longer. These variations are usually discussed in terms of variations in the length of the day (LoD) and are caused by processes acting within the interior, at the surface and outside of the Earth. Here, we investigate the presence of long-standing decadal variations in yearl...

Braginsky, S. I.: Short-period geomagnetic secular variation, Geophys. Astrophys. Fluid Dynam., 30, 1–78, 1984.; Buffet, B. A.: A mechanism for decade fluctuations in the length of day, Geophys. Res. Lett., 23, 3803–3806, 1996.; Currie, R. G.: The 60 year spectral line in length of day fluctuations, S. Afr. J. Sci., 69, 180–182, 1973.; Flandrin, P., Rilling, G., and Goncalvès, P., Empirical mode decomposition as a filter bank, EEE Sig. Proc. Lett., 11, 112–114, 2004.; Gi...

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An Artificial Neural Network Predictor for Tropospheric Surface Du...

By: N. A. Dris; T. D. Xenos; I. N. Dimou; S. A. Isaakidis

Description: Aristotle University of Thessaloniki, Department of Electrical and Computer Engineering, 54006 Thessaloniki, Greece. In this work, an artificial neural network (ANN) model is developed and used to predict the presence of ducting phenomena for a specific time, taking into account ground values of atmospheric pressure, relative humidity and temperature. A feed forward backpropagation ANN is implemented, which is trained, validated and tested using atmosphe...

Babin, S. M., Young, G. S., and Carton, J. E.: A New Model of the Oceanic Evaporation Duct. J. of Applied Meteorology, American Meteorological Society, 36, 193–204, 1997.; Burges, C. J. C.: A Tutorial on Support Vector Machines for Pattern Recognition., Data Min. Knowl. Disc., 2, 121–167, 1998.; Nello Cristianini, N. and Shawe-Taylor, J.: An Introduction to Support Vector Machines and other kernel-based learning methods, Cambridge University Press, 211–231, 2000.; Fawcet...

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Use of the Breeding Technique to Estimate the Structure of the Ana...

By: S.-c. Yang; E. Kalnay; D. J. Patil; M. Cai; R. Morss; J. A. Yorke; I. Szunyogh; M. Corazza; B. R. Hunt

Description: University of Maryland, College Park, MD 20742-2425, USA. A 3D-variational data assimilation scheme for a quasi-geostrophic channel model (Morss, 1998) is used to study the structure of the background error and its relationship to the corresponding bred vectors. The "true" evolution of the model atmosphere is defined by an integration of the model and "rawinsonde observations" are simulated by randomly perturbing the true state at fix...

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Ion Motion in the Current Sheet with Sheared Magnetic Field – Part...

By: A. I. Neishtadt; L. M. Zelenyi; A. V. Artemyev

Description: Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow, Russia. We present a theory of trapped ion motion in the magnetotail current sheet with a constant dawn–dusk component of the magnetic field. Particle trajectories are described analytically using the quasi-adiabatic invariant corresponding to averaging of fast oscillations around the tangential component of the magnetic field. We consider particle dynamics in the quasi-adiaba...

Anastasiadis, A., Gontikakis, C., and Efthymiopoulos, C.: Particle Interactions with Single or Multiple 3D Solar Reconnecting Current Sheets, Sol. Phys., 253, 199–214, doi:10.1007/s11207-008-9234-4, 2008.; Arnold, V. I.: Catastrophe Theory, Springer-Verlag, Berlin, 3rd Edn., 1992.; Arnold, V. I., Kozlov, V. V., and Neishtadt, A. I.: Mathematical Aspects of Classical and Celestial Mechanics, Dynamical Systems III. En...

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Separating Fast and Slow Modes in Coupled Chaotic Systems : Volume...

By: E. Kalnay; M. Peña

Description: SAIC at Environmental Modeling Center, NCEP, Camp Springs, Maryland, USA. We test a simple technique based on breeding to separate fast and slow unstable modes in coupled systems with different time scales of evolution and variable amplitudes. The technique takes advantage of the earlier saturation of error growth rate of the fastest mode and of the lower value of the saturation amplitude of perturbation of either the fast or the slow modes. These prope...

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Time-dependent Prediction Degredation Assessment of Neural-network...

By: S. S. Kouris; A. Casimiro; Th. D. Xenos

Description: Department of Electrical and Comp. Eng., Univ. of Thessaloniki, Greece. An estimation of the difference in TEC prediction accuracy achieved when the prediction varies from 1 h to 7 days in advance is described using classical neural networks. Hourly-daily Faraday-rotation derived TEC measurements from Florence are used. It is shown that the prediction accuracy for the examined dataset, though degrading when time span increases, is always ...

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Generation of Zonal Flows by Rossby Waves in the Atmosphere : Volu...

By: P. K. Shukla; R. Z. Sagdeev; O. A. Pokhotelov; L. Stenflo; O. G. Onishchenko

Description: Institute of Physics of the Earth, 12 3810 Moscow, 10 B. Gruzinskaya Str., Russia. A novel mechanism for the short-scale Rossby waves interacting with long-scale zonal flows in the Earth's atmosphere is studied. The model is based on the parametric excitation of convective cells by finite amplitude Rossby waves. We use a set of coupled equations describing the nonlinear interaction of Rossby waves and zonal flows which admits the excitation of zonal flo...

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Tempting Long-memory - on the Interpretation of Dfa Results : Volu...

By: D. Maraun; H. W. Rust; J. Timmer

Description: Department of Physics, Potsdam University, D-14415 Potsdam, Germany. We study the inference of long-range correlations by means of Detrended Fluctuation Analysis (DFA) and argue that power-law scaling of the fluctuation function and thus long-memory may not be assumed a priori but have to be established. This requires the investigation of the local slopes. We account for the variability characteristic for stochastic processes by calculating empiric...

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Time Dependent Long's Equation : Volume 1, Issue 2 (10/11/2014)

By: M. Humi

Description: Department of Mathematical Sciences, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA. Long's equation describes steady-state two-dimensional stratified flow over terrain. Its numerical solutions under various approximations were investigated by many authors. Special attention was paid to the properties of the gravity waves that are predicted to be generated as a result. In this paper we derive a time-dependent generali...

Durran, D. R.: Two-layer solutions to Long's equation for vertically propagating mountain waves, Q. J. Roy. Meteorol. Soc., 118, 415–433, 1992.; Drazin, P. G.: On the steady flow of a fluid of variable density past an obstacle, Tellus, 13, 239–251, 1961.; Drazin, P. G. and Moore, D. W.: Steady two dimensional flow of fluid of variable density over an obstacle, J. Fluid. Mech., 28, 353–370, 1967.; Baines, P. G.: Topographic Effects in Stratified Flows, Cambridge Univ. Pre...

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Estimation of Sedimentary Proxy Records Together with Associated U...

By: K. Rehfeld; S. Prasad; J. Heitzig; B. Goswami; J. Kurths; A. Ambili; N. Marwan

Description: Potsdam Institute for Climate Impact Research, Transdisciplinary Concepts & Methods, 14412 Potsdam, Germany. Sedimentary proxy records constitute a significant portion of the recorded evidence that allow us to investigate paleoclimatic conditions and variability. However, uncertainties in the dating of proxy archives limit our ability to fix the timing of past events and interpret proxy record inter-comparisons. While there are various ag...

Anoop, A., Prasad, S., Plessen, B., Basavaiah, N., Gaye, B., Naumann, R., Menzel, P., Weise, S., and Brauer, A.: Palaeoenvironmental implications of evaporative Gaylussite crystals from Lonar lake, Central India, J. Quaternary Sci., 28, 349–359, 2013.; Blaauw, M.: Methods and code for classical age-modelling of radiocarbon sequences, Quat. Geochronol., 5, 512–518, 2010.; Blaauw, M., Christen, J. A., Mauquoy, D., van der Plicht, J., and Bennett, K.: Testing the timing of ...

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Nonequilibrium Plankton Community Structures in an Ecohydrodynamic...

By: N. Shigesada; H. Malchow

Description: Dept. of Water Modelling & Wadden Sea Research, Inst. of Physics, GKSS Research Centre, Max-Planck-Strasse, D-21502 Geesthacht, Germany. Due to the local and global impacts of algae blooms and patchiness on water quality, carbon cycling and climate, models of plankton dynamics are of current interest. In this paper, the temporal and spatial patterns in natural plankton communities are interpreted as transient and stationary nonequilibrium solutions of dy...

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Features of Criticality in Precursory Seismic Electric Signals and...

By: E. Dologlou

Description: Solid State Section, Department of Physics, University of Athens, Panepistimiopolis, Zografou, 157 84 Athens, Greece. Very recently the recordings of precursory seismic electric signals (SESsf) in the island of Kozu-shima, Japan, have been reported, and their interrelation with subsequent earthquakes was shown to be beyond chance. Almost simultaneously, the recording of SES activity in northern Greece was also...

Andersen, J. V., Sornette, D., and Leung, K.-T.: Tri-critical behavior in rupture induced by disorder, Phys. Rev. Lett., 78, 2140–2143, 1997.; Dologlou, E.: Power law relationship between parameters of earthquakes and precursory electrical phenomena, Nat. Hazards Earth Syst. Sci., 8, 977–983, doi:10.5194/nhess-8-977-2008, 2008a.; Dologlou, E.: Possible relationship between Seismic Electric Signals (SES) lead time and...

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A Nudging-based Data Assimilation Method: the Back and Forth Nudgi...

By: D. Auroux; J. Blum

Description: Institut de Mathématiques de Toulouse, Université Paul Sabatier Toulouse 3, 31062 Toulouse Cedex 9, France. This paper deals with a new data assimilation algorithm, called Back and Forth Nudging. The standard nudging technique consists in adding to the equations of the model a relaxation term that is supposed to force the observations to the model. The BFN algorithm consists in repeatedly performing forward and backward integrations of the model with rel...

Arnold, M. and Datta, B N.: Single-input eigenvalue assignment algorithms: A close look, SIAM J. Matrix Anal. Appl., 19(2), 444–467, 1998.; Auroux, D.: Etude de différentes méthodes d'assimilation de données pour l'environnement, Ph.D. thesis, University of Nice Sophia-Antipolis, 2003.; Auroux, D. and Blum, J.: Data assimilation methods for an oceanographic problem, vol. XVI of Mathematics in Industry Series: Multidisciplinary methods for analysis, optimization and contr...

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A Novel Method for Analyzing the Process of Abrupt Climate Change ...

By: W. Hou; G. L. Feng; P. C. Yan

Description: College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. A climate system which is transitioning from one state to another is known as an abrupt climate change. Most of the recent studies regarding abrupt climate change have focused on the changes occurring before and after the abrupt change point, while little attention has been given to the transition process which occurs when the system breaks away from the original state to a new state. ...

Alexander, R., Reinhard, C., and Andrey, G.: Multistability and critical thresholds of the Greenland ice sheet, Nat. Clim. Change, 2, 429–432, 2012.; Alley, R. B., Marotzke, J., Nordhaus, W. D., Overpeck, J. T., Peteet, D. M., Pielke, R. A., Pierrehumbert Jr., R. T., Rhines, P. B., Stocker, T. F., Talley, L. D., and Wallace, J. M.: Abrupt climate change, Science, 299, 2005–2010, 2003.; Baker, M. B. and Charlson, R, J.: Bistability of CCN concentrations and thermodynamics...

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Non-extensivity and Long-range Correlations in the Earthquake Acti...

By: F. Vallianatos; P. Sammonds; G. Michas

Description: Institute for Risk and Disaster Reduction, University College London, Gower Street, London, WC1E 6BT, UK. In the present work the statistical properties of the earthquake activity in a highly seismic region, the West Corinth rift (Central Greece), are being studied by means of generalized statistical physics. By using a dataset that covers the period 2001–2008, we investigate the earthquake energy distribution and the distribution of the time intervals (...

Abe, S. and Suzuki, N.: Law for the distance between successive earthquakes, J. Geophys. Res., 108, 2113, doi:10.1029/2002JB002220, 2003.; Abe, S. and Suzuki, N.: Scale-free statistics of time interval between successive earthquakes, Physica A, 350, 588–596, doi:10.1016/j.physa.2004.10.040, 2005.; Ambraseys, N. N. and Jackson, J. A.: Seismicity and associated stra...

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Multi-scale Interactions of Geological Processes During Mineraliza...

By: Q. Cheng; L. Yao

Description: State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China. Relations between mineralization and certain geological processes are established mostly by geologist's knowledge of field observations. However, these relations are descriptive and a quantitative model of how certain geological processes strengthen or hinder mineralization is not clear, that is to say, the mechanism of the interactio...

Agterberg, F.: New applications of the model of de Wijs in regional geochemistry, Math. Geol., 39, 1–25, doi:10.1007/s11004-006-9063-7, 2007{a}.; Agterberg, F. and Cheng, Q.: Conditional independence test for weights-of-evidence modelling, Natural Resources Research, 11, 249–255, doi:10.1023/A:1021193827501, 2002.; Agterberg, F., Bonham-Carter, G., and Wright, D....

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Bayesian Modeling and Significant Features Exploration in Wavelet ...

By: F. Godtliebsen; D. V. Divine

Description: Department of Mathematics and Statistics, Faculty of Science, University of Troms\o, 9037, Norway. This study proposes and justifies a Bayesian approach to modeling wavelet coefficients and finding statistically significant features in wavelet power spectra. The approach utilizes ideas elaborated in scale-space smoothing methods and wavelet data analysis. We treat each scale of the discrete wavelet decomposition as a sequence of independent random variab...

Berger, J. (Ed.): Statistical decision theory and Bayesian analysis, Springer Verlag, 1985.; Box, E., Jenkins, G., and Reinsel, G.: Time series analysis: Forecasting and control, Prentice-Hall, Englewood Cliffs, 1994.; Chaudhuri, P. and Marron, J.: SiZer for exploration of structures in curves, J. Am. Statist. Assoc., 94, 807–823, 1999.; Dansgaard, W., Johnsen, S., Clausen, H., Dahl-Jensen, D., Gundestrup, N., Hammer, C., Hvidberg, C., Steffensen, J., Sveinbjornsdottir, ...

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Mhd Effects of the Solar Wind Flow Around Planets : Volume 7, Issu...

By: C. J. Farrugia; N. V. Erkaev; D. F. Vogl; H. K. Biernat; W. Schaffenberger

Description: Space Research Institute, Austrian Academy of Sciences, Graz, Austria. The study of the interaction of the solar wind with magnetized and unmagnetized planets forms a central topic of space research. Focussing on planetary magnetosheaths, we review some major developments in this field. Magnetosheath structures depend crucially on the orientation of the interplanetary magnetic field, the solar wind Alfvén Mach number, the shape of the obstacle (axisymme...

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Solar Wind Interaction with the Earth's Magnetosphere: the Role of...

By: F. Valentini; M. Faganello; F. Pegoraro; F. Califano

Description: Physics Dept., University of Pisa, Pisa, Italy. The Earth's magnetosphere and solar wind environment is a laboratory of excellence for the study of the physics of collisionless magnetic reconnection. At low latitude magnetopause, magnetic reconnection develops as a secondary instability due to the stretching of magnetic field lines advected by large scale Kelvin-Helmholtz vortices. In particular, reconnection takes place in the sheared magnetic layer th...

Attico, N., Califano, F., and Pegoraro, F.: Fast collisionless reconnection in the whistler frequency range, Phys. Plasmas, 7, 2381–2387, doi:10.1063/1.874076, 2000.; Bian, N. and Vekstein, G.: On the two-fuid modification of the resistive tearing instability, Phys. Plasmas, 14, 120702, doi:10.1063/1.2820904, 2007.; Belmont, G. and Chanteur, G.: Kelvin-Helmholtz instability: nonlinear evolution, in: Turbulence and Nonlinear Dynamics in MHD Flows, edited by: Meneguzzi, M....

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