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Development and Analysis of a Simple Model to Represent the Zero R...

By: D. Schertzer; I. Tchiguirinskaia; S. Lovejoy; A. Gires

Description: Université Paris Est, Ecole des Ponts ParisTech, LEESU, Marne-la-Vallée, France. High-resolution rainfall fields contain numerous zeros (i.e. pixels or time steps with no rain) which are either real or artificial – that is to say associated with the limit of detection of the rainfall measurement device. In this paper we revisit the enduring discussion on the source of this intermittency, e.g. whether it requires specific modelling. We first review the f...

de Lima, M. I. P. and de Lima, J. L. M. P.: Investigating the multifractality of point precipitation in the Madeira archipelago, Nonlin. Processes Geophys., 16, 299–311, doi:10.5194/npg-16-299-2009, 2009.; de Lima, M. I. P. and Grasman, J.: Multifractal analysis of 15-min and daily rainfall from a semi-arid region in Portugal, J. Hydrol., 220, 1–11, 1999.; de Montera, L., Barthes, L., Mallet, C., and Gole, P.: The Eff...

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...

Coronal Heating and Wind Acceleration by Nonlinear Alfvén Waves – ...

By: T. K. Suzuki

Description: School of Arts and Sciences, University of Tokyo, Komaba, Meguro, 153-8902 Tokyo, Japan. We review our recent results of global one-dimensional (1-D) MHD simulations for the acceleration of solar and stellar winds. We impose transverse photospheric motions corresponding to the granulations, which generate outgoing Alfvén waves. We treat the propagation and dissipation of the Alfvén waves and consequent heating from the photosphere by dynamical simulatio...

Chandran, B. D. G.: Weak Compressible Magnetohydrodynamic Turbulence in the Solar Corona Phys. Rev. Lett., 95, 265004, 2005.; Boynton, G. C. and Torkelsson, U.: Dissipation of nonlinear Alfvén waves, Astron. Astrophys., 308, 299–308, 1996.; Airapetian, V. S., Ofman, L., Robinson, R. D., Carpenter, K., and Davila, J.: Winds from Luminous Late-Type Stars. I. The Effects of Nonlinear Alfvén Waves, Astrophys. J., 528, 965–971, 2000.; Axford, W. I. and McKenzie, J. F.: The So...

Seasonal Variability of the Subpolar Gyres in the Southern Ocean: ...

By: C. Horenkamp; G. Froyland; K. Padberg-gehle; M. Dellnitz; A. Sen Gupta

Description: Department of Mathematics, University of Paderborn, 33095 Paderborn, Germany. The detection of regions in the ocean that are coherent over an extended period of time is a fundamental problem in many oceanic applications. For instance such regions are important for studying the transport of marine species and for the distribution of nutrients. In this study we demonstrate the efficacy of transfer operators in detecting and analysing such structures. We f...

Aumont, O., Orr, J., Jamous, D., Monfray, P., Marti, O., and Madec, G.: A degradation approach to accelerate simulations to steady-state in a 3-D tracer transport model of the global ocean, Clim. Dynam., 14, 101–116, 1998.; Barnier, B., Madec, G., Penduff, T., Molines, J.-M., Treguier, A.-M., Sommer, J. L., Beckmann, A., Biastoch, A., Boening, C., Dengg, J., Derval, C., Durand, E., Gulev, S., Remy, E., Talandier, C., Theetten, S., Maltrud, M., McClean, J., and De Cuevasm...

Comment on Obliquely Propagating Large Amplitude Solitary Waves in...

By: E. Dubinin; K. Sauer; J. F. McKenzie

Description: Schools of Pure and Applied Physics and Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa. No abstract available.

Adlam, J. H. and Allen, E.: The structure of strong collision-free hydromagnetic waves, Phil. Mag., 3, 448, 1958.; Braginskii, S. I.: Transport processes in a plasma, in: Reviews of Plasma Physics, v. 1, edited by: Leontovich, M. A., Consultants Bureau, New-York, 1965.; Chen, F. F.: in: Plasma Physics. Controlled Fusion, p. 77, Plenum Press, New-York, 1984.; Dubinin, E., Sauer, K., and McKenzie, J. F.: Nonlinear stationary whistler waves and whistler solitons (oscilliton...

Excitation of Low Frequency Oscillations in a Planetary Magnetoshe...

By: N. Borisov; M. Fränz

Description: Institute of Terrestrial Magnetism, Ionosphere and Radio Waves Propagation, (IZMIRAN), 142190 Troitsk, Moscow region, Russia. We show that the slow magnetosonic (SM) perturbations generated in the vicinity of the magnetopause, due to the excitation of the Kelvin-Helmholtz (K.-H.) instability in the case of a supersonic flow velocity, are transformed into fast magnetosonic (FM) waves which can propagate into the magnetosheath. Under the conditions discuss...

Anderson, B. J. and Fuselier, S. A.: Magnetic pulsations from 0.1 Hz to 4.0 Hz and associated plasma properties in the Earth's subsolar magnetosheath and plasma depletion layer, J. Geophys. Res., 98, 1461–1479, 1993.; Biernat, H. K., Erkaev, N. V., Amerstofer U. V., Penz, T., and Lichtenegger, H. I. M.: Solar wind flow past Venus and its applications for the occurrence of the Kelvin-Helmholtz instability, Planet. Space Sci., 55, 1793–1803, 2007.; Chandrasekhar, S.: Hydro...

Kinetic Simulations of the Coupling Between Current Instabilities ...

By: J. Büchner; T. Wiegelmann

Description: Max-Planck Institut für Aeronomie, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany. We investigate the coupling between current and tearing instability modes of a thin current sheet using the particle code GISMO. We identify pure tearing modes (kx≠ 0), instabilities in the current flow direction (ky≠ 0) and general 3D reconnection modes (kx≠ 0 and ky≠ 0). Our results give evidence that the coupling between ...

Multi-scale Analysis of Teleconnection Indices: Climate Noise and ...

By: C. Franzke

Description: British Antarctic Survey, Natural Environment Research Council, Cambridge, UK. The multi-scale nature and climate noise properties of teleconnection indices are examined by using the Empirical Mode Decomposition (EMD) procedure. The EMD procedure allows for the analysis of non-stationary time series to extract physically meaningful intrinsic mode functions (IMF) and nonlinear trends. The climatologically relevant monthly mean teleconnection indices of th...

Bengtsson, L., Hagemann, S., and Hodges, K. I.: Can climate trends be calculated from reanalysis data?, J. Geophys. Res., 109, D11111, doi:10.1029/2004JD004536.; Cash, B. A. and Lee, S.: Observed Nonmodal Growth of the Pacific-North American Teleconnection Pattern, J. Climate, 14, 1017–1028, 2001.; Crommelin, D. T. and Vanden-Eijnden, E.: Reconstruction of Diffusions using spectral data from timeseries, Comm. Math. Sci., 4, 651–668, 2006.; Czaja, A., Robertson, A. W., an...

Site Effect Classification Based on Microtremor Data Analysis Usin...

Description: Department of Mining Engineering, Faculty of Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran. The aim of this study is to classify the site effect using concentration–area (CA) fractal model in Meybod city, central Iran, based on microtremor data analysis. Log–log plots of the frequency, amplification and vulnerability index (kg) indicate a multifractal nature for the parameters in the area. The resul...

Architectural Institute of Japan: Earthquake Motion and Ground Condition, AIJ, AIJ, 5-26-20 Shiba, Minato-ku, Tokyo 108, Japan, 1993.; Afzal, P., Fadakar Alghalandis, Y., Khakzad, A., Moarefvand, P., and Rashidnejad Omran, N.: Delineation of mineralization zones in porphyry Cu deposits by fractal concentration-volume modeling, J. Geochem. Explor., 108, 220–232, 2011.; Afzal, P., Dadashzadeh Ahari, H., Rashidnejad Omran, N., and Aliyari, F.: Delineation of gold mineralize...

Evolution of Atmospheric Connectivity in the 20Th Century : Volume...

By: M. Barreiro; A. C. Martí; F. Arizmendi

Description: Instituto de Física, Facultad de Ciencias, Universidad de la República, Igua 4225, Montevideo, Uruguay. We aim to study the evolution of the upper atmosphere connectivity over the 20th century as well as to distinguish the oceanically forced component from the atmospheric internal variability. For this purpose we build networks from two different reanalysis data sets using both linear and nonlinear statistical similarity measures to determine the existe...

Albert, R. and Barabási, A. L.: Statistical mechanics of complex networks, Rev. Mod. Phys., 74, 47–97, 2002.; Bandt, C. and Pompe, B.: Permutation entropy: A natural complexity measure for time series, Phys. Rev. Lett., 88, 174102, 2002.; Barab\'asi, A. L. and Albert, R.: Emergence of scaling in random networks, Science, 286, 509–512, 1999.; Barreiro, M.: Influence of ENSO and the South Atlantic Ocean on climate predictability over Southeastern South America, Clim. Dynam...

Logit-normal Mixed Model for Indian Monsoon Precipitation : Volume...

By: S. Chatterjee; L. R. Dietz

Description: University of Minnesota, School of Statistics, Minneapolis, Minnesota, USA. Describing the nature and variability of Indian monsoon precipitation is a topic of much debate in the current literature. We suggest the use of a generalized linear mixed model (GLMM), specifically, the logit-normal mixed model, to describe the underlying structure of this complex climatic event. Four GLMM algorithms are described and simulations are performed to vet the...

Ajayamohan, R., Merryfield, W., and Kharin, V.: Increasing trend of synoptic activity and its relationship with extreme rain events over central India, J. Climate, 23, 1004–1013, 2008.; Attri, S. D. and Tyagi, A.: Climate Profile of India, Tech. rep., Government of India, Ministry of Earth Sciences, India Meteorological Department, New Delhi, India, 2010.; Bates, D.: lme4: Mixed-effects modeling with R (Preprint), Springer,

Size-frequency Relation of Earthquakes in Load-transfer Models of ...

By: A. F. Pacheco; D. Iñiguez; J. B. Gómez

Description: Department of Geological Sciences, University College London, Gower Street, London WC1 6BT,U.K.. Using Monte Carlo simulations of the process of breaking in arrays of elements with load-transfer rules, we have obtained the size- frequency relation of the avalanches occurring in 1- and 2-dimensional stochastic fracture models. The resulting power-law behaviour resembles the Gutenberg-Richter law for the relation between the size (liberated energy) of eart...

Estimation of Flow Velocity for a Debris Flow Via the Two-phase Fl...

By: P. Xu; Y. Gao; Z. Zheng; S. Guo

Description: School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China. The two-phase fluid model is applied in this study to calculate the steady velocity of a debris flow along a channel bed. By using the momentum equations of the solid and liquid phases in the debris flow together with an empirical formula to describe the interaction between two phases, the steady velocities of the solid and liquid phases are obta...

Anderson, T. B. and Jackson, R.: Fluid mechanical description of fluidized beds: equations of motion, Ind. Eng. Chem. Fundam., 6, 527–539, 1967.; Bagnold, R. A.: Experiments on a gravity-free dispersion of large solid spheres in a Newtonian fluid under shear, Proc. R. Soc. Lond. Ser. A, 225, 49–63, 1954.; Brunelli, S.: Trasporto solido annuo dei corsi d'acqua in funzione delle loro caratteristiche idrologiche e morfologiche, Tesi di Laurea, Università degli Studi di Pado...

On the Kalman Filter Error Covariance Collapse Into the Unstable S...

By: L. Palatella; A. Trevisan

Description: Istituto di Scienze dell'Atmosfera e del Clima del CNR, via Gobetti 101, 40129 Bologna, Italy. When the Extended Kalman Filter is applied to a chaotic system, the rank of the error covariance matrices, after a sufficiently large number of iterations, reduces to N+ + N0 where N+ and N0 are the number of positive and null Lyapunov exponents. This is due to the collapse into the unstable a...

Evensen, G.: Sequential data assimilation with a nonlinear quasi-geostrophic model using Monte Carlo methods to forecast error statistics, J. Geophys. Res., 99, 10143–10162, 1994.; Ghil, M. and Malanotte Rizzoli, P.: Data assimilation in meteorology and oceanography, Adv. Geophys., 33, 141–266, 1991.; Golub, G. H. and von Loan, C. F.: Matrix Computation, John Hopkins University Press, Baltimore and London, 3$^{\rm rd}$ Edition, ISBN 0-8018-5413-X, 1996.; Hamill, T. M. an...

Multi-point Observations of Intermittency in the Cusp Regions : Vo...

By: T. Chang; H. Lamy; M. M. Echim

Description: Belgian Institute for Space Aeronomy, Avenue Circulaire 3, 1180 Bruxelles, Belgium. In this paper we investigate the statistical properties of magnetic field fluctuations measured by the four Cluster spacecraft in the cusp and close to the interface with the magnetospheric lobes, magnetopause and magnetosheath. At lower altitudes along the outbound orbit of 26 February 2001, the magnetic field fluctuations recorded by all four spacecraft are random and ...

Alexandrova, O., Mangeney, A., Maksimovici, M., et al.: Alfvén vortex filaments observed in the magnetosheath downstream of a quasi-perpendicular bow shock, J. Geophys. Res., 111, A12208, doi:10.1029/2006JA011934, 2006.; Balogh, A., Carr, C. M., Acuna, M. H., et al.: The Cluster Magnetic Field Instrument: overview of in-flight performance and initial results, Ann. Geophys., 19, 1207–1217, 2001.; Bruno, R., Carbone, V., Veltri, P., et al.: Identifying intermittency events...

Instability and Change Detection in Exponential Families and Gener...

By: S. Chatterjee; Y. Lu

Description: Amazon.com, Seattle, Washington, USA. Exponential family statistical distributions, including the well-known Normal, Binomial, Poisson, and exponential distributions, are overwhelmingly used in data analysis. In the presence of covariates, an exponential family distributional assumption for the response random variables results in a generalized linear model. However, it is rarely ensured that the parameters of the assumed distributions are stable throug...

Albers, W. and Kallenberg, W. C. M.: CUMIN Charts, Metrika, 70, 111–130, 2009.; Alwan, L. C.: Designing an Effective EF-CUSUM Chart without the Use of Nomographs, Commun. Stat. A-Theor., 29, 2879–2893, 2000.; Atienza, O. O., Tang, L. C., and Ang, B. W.: A Uniform Most Powerful Cumulative Sum Scheme Based on Symmetry, J. Roy. Stat. Soc. D-Sta., 49, 209–217, 2000.; Bolton, R. J. and Hand, D. J.: Statistical fraud detection: A review, Stat. Sci., 17, 235–255, 2002.; Brown, ...

A Model for Large-amplitude Internal Solitary Waves with Trapped C...

By: K. R. Helfrich; B. L. White

Description: Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, USA. Large-amplitude internal solitary waves in continuously stratified systems can be found by solution of the Dubreil-Jacotin-Long (DJL) equation. For finite ambient density gradients at the surface (bottom) for waves of depression (elevation) these solutions may develop recirculating cores for wave speeds above a critical value. As typically modeled, these recir...

Aigner, A. and Grimshaw, R.: Numerical simulations of the flow of a continuously stratified fluid, incorporating inertial effects, Fluid Dyn. Res., 28, 323–347, 2001.; Aigner, A., Broutman, D., and Grimshaw, R.: Numerical simulations of internal solitary waves with vortex cores, Fluid Dyn. Res., 25, 315–333, 1999.; Akylas, T. and Grimshaw, R.: Solitary internal waves with oscillatory tails, J. Fluid Mech., 242, 279–298, 1992.; Barad, M. F. and Fringer, O. B.: Simulations...

Constrained Robust Estimation of Magnetotelluric Impedance Functio...

By: D. Sutarno

Description: Physics of Complex System Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia. Robust impedance estimation procedures are now in standard use in magnetotelluric (MT) measurements and research. These always yield impedance estimates which are better than the conventional least square (LS) estimation because the 'real' MT data almost never satisfy the statistical assumptions of Gaussian distribution upon which norma...

Chave, A. D. and Thomson, D. J.: Some comments on magnetotelluric response function estimation, J. Geophys. Res., 94, 14 215–14 225, 1989.; Boehl, J. E., Bostick, F. X., and Smith, H. W.: An application of the Hilbert transform to the magnetotelluric method, Tech. Rep. Electr. Geophys. Res. Lab., University of Texas, Austin, 1977.; Chave, A. D. and Thomson, D. J.: A bounded influence regression M-estimator based on the statistic of the hat matrix, J. Roy. Stat. Soc., Ser...

Climate of Utopia : Volume 15, Issue 4 (07/07/2008)

By: M. Gedalin; M. Balikhin

Description: Department of Physics, Ben-Gurion University, Beer-Sheva, Israel. Climate is usually considered to depend on a large number of parameters, this being essentially a functional in multi-dimensional parameter space. We propose a low-dimensional model of a climate where the temperature field on a thermally conducting planet depends on the external energy input and very limited number of internal parameters, like thermal conductivity and reflectivity. Equili...

Alley, R. B., Marotzke, J., Nordhauset, W. D., et al.: Abrupt climate change, Science, 299, 2005–2010, 2003.; Boer, G. J., Hamilton, K., and Zhu, W., Climate sensitivity and climate change under strong forcing, Clim. Dynam., 24, 685–700, 2005.; Braun, H., Christl, M., Rahmstorf, S., et al.: Possible solar origin of the 1,470-year glacial climate cycle demonstrated in a coupled model, Nature, 438, 208–211, 2005.; Braun, H., Ganopolski, A., Christl, M., and Chialvo, D. R.:...

Earthquake Sequencing: Chimera States with Kuramoto Model Dynamics...

By: M. Cavers; K. Vasudevan; A. Ware

Description: Department of Mathematics and Statistics, University of Calgary, Calgary, Alberta, T2N 1N4, Canada. Earthquake sequencing studies allow us to investigate empirical relationships among spatio-temporal parameters describing the complexity of earthquake properties. We have recently studied the relevance of Markov chain models to draw information from global earthquake catalogues. In these studies, we considered directed graphs as graph theoretic representa...

Abrams, D. M. and Strogatz, S. H.: Chimera states for coupled oscillators, Phys. Rev. Lett., 93, 174102, doi:10.1103/PhysRevLett.93.174102, 2004.; Abrams, D. M., Mirollo, R., Strogatz, S. H., and Wiley, D. A.: Solvable model for chimera states of coupled oscillators, Phys. Rev. Lett., 101, 084103, doi:10.1103/PhysRevLett.101.084103, 2008.; Arenas, A., ...

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