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On the Dependence of Third- and Fourth-order Moments on Stability ...

By: A. Maurizi

Description: Institute of Atmospheric Sciences and Climate via Gobetti 101,I-40129 Bologna, Italy. Analysis of published data on the third- and fourth-order moments of vertical velocity in the atmospheric boundary layer is performed, and it is shown that turbulence is non-Gaussian even when almost symmetric. It is also proposed that the relationship between third- and fourth-order moments depends on stability. New data from a wind tunnel experiment roughly support t...

Alberghi, S., Maurizi, A., and Tampieri, F.: Relationship between the vertical velocity skewness and kurtosis observed during sea-breeze convection, J. Appl. Meteorol., 41, 885-889, 2002.; Anfossi, D., Ferrero, E., Sacchetti, D., and Trini Castelli, S.: Comparison among empirical probability density functions of the vertical velocity in the surface layer based on higher order correlations, Boundary-Layer Meteorol., 82, 193-218, 1997.; Baskaran, V., Smits, A J., and Joube...

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Earthquake Simulations with Time-dependent Nucleation and Long-ran...

By: J. H. Dieterich

Description: U.S. Geological Survey, 345 Middlefield Road, MS/977, Menlo Park, California 94025, USA. A model for rapid simulation of earthquake sequences is introduced which incorporates long-range elastic interactions among fault elements and time-dependent earthquake nucleation inferred from experimentally derived rate- and state-dependent fault constitutive properties. The model consists of a planar two-dimensional fault surface which is periodic in both the x...

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Synchronization in a Coupled Two-layer Quasigeostrophic Model of B...

By: P. L. Read; A. A. Castrejón-pita

Description: Atmospheric, Oceanic & Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK. Synchronization is studied using a pair of diffusively-coupled, two-layer quasi-geostrophic systems each comprising a single baroclinic wave and a zonal flow. In particular, the coupling between the systems is in the well-known master-slave or one-way configuration. Nonlinear time series analysis, phase dynamics, and bifurcation diagram...

Andrews, D.: An Introduction to Atmospheric Physics, Cambridge University Press, pp. 140–153, 2000.; Anishchenko, V. S., Silchenko, A. N., and Khovanov, I. A.: Synchronization of switching processes in coupled Lorenz systems, Phys. Rev. E, 57(1), 316–322, 1998.; Appleby, J.: Comparative theoretical and experimental studies of baroclinic waves in a two-layer system, PhD Thesis, University of Leeds, UK, 1982.; Boccaletti, S., Kurths, J., Osipov, G., Valladares, D. K., and ...

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Characteristic Scales in Landslide Modelling : Volume 16, Issue 4 ...

By: R. Di Maio; L. Milano; E. Piegari

Description: Dipartimento di Scienze della Terra, Napoli, Italy. Landslides are natural hazards occurring in response to triggers of different origins, which can act with different intensities and durations. Despite the variety of conditions that cause a landslide, the analysis of landslide inventories has shown that landslide events associated with different triggers can be characterized by the same probability distribution. We studied a cellular automaton, able t...

Christensen, K. and Olami, Z.: Scaling, phase transitions, and nonuniversality in a self-organized critical cellular-automaton model, Phys. Rev. A., 46, 1829–1838, 1992.; Fredlund, D. G. and Rahardjo H.: Soil Mechanics for Unsatured Soils, Wiley-Interscience, New York, 1993.; Dietrich, W. E., Reiss, R., Hsu, M. L., and Montgomery, D.: A process-based model for colluvial soil depth and shallow landslides using digital elevation data, Hydrol. Processes, 9, 383–400, 1995.; ...

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A Weakly Nonlinear Model for Multi-modal Evolution of Wind-generat...

By: L. G. Redekopp; T. Sakai

Description: Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA. A weakly nonlinear evolution model that accounts for multi-modal interaction in a small, continuously stratified lake of variable depth is derived. In particular, an evolution model for the first two vertical modes in a lake that is subject to wind stress forcing is numerically simulated. Defining modal energies, energy transfer between ...

Antenucci, J., Imberger, J., and Saggio, A.: Seasonal evolution of the basin-scale internal wave field in a large stratified lake, Limnol. Oceanogr., 45(7), 1621–1638, 2000.; Baines, P. G.: Topographic effects in strafified flows, Cambridge University press, , 1995.; Boehrer, B.: Modal response of a deep stratified lake: western Lake Constance, J. Goephys. Res., 105, 28837–28845, 2000.; Bogucki, D. J., Redekopp, L. G., and Barth, J.: Internal solitary waves in the coasta...

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Logit-normal Mixed Model for Indian Monsoon Rainfall Extremes : Vo...

By: L. R. Dietz; S. Chatterjee

Description: University of Minnesota, School of Statistics, Minneapolis, Minnesota, USA. Describing the nature and variability of Indian monsoon rainfall extremes 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. Several GLMM algorithms are described and simulations are performed to...

Attri, S. D. and Tyagi, A.: Climate Profile of India, Tech. rep., Government of India, Ministry of Earth Sciences, India Meteorological Department, 2010.; Breslow, N. and Clayton, D.: Approximate inference in generalized linear mixed models, J. Am. Stat. Assoc.,88, 9–25, 1993.; Ghosh, S., Luniya, V., and Gupta, A.: Trend analysis of Indian summer monsoon rainfall at different spatial scales, Atmos. Sci. Lett., 10, 285–290, 2009.; Bates, D.: lme4: Mixed-Effects Modeling l...

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Quasiadiabatic Description of Nonlinear Particle Dynamics in Typic...

By: A. I. Neishtadt; L. M. Zelenyi; J. Büchner; D. L. Vainchtein

Description: Space Research Institute, ul.Profsouznaya, 84/32, Moscow, Russia, GSP-7, 117997. In the present paper we discuss the motion of charged particles in three different regions of the Earth magnetotail: in the region with magnetic field reversal and in the vicinities of neutral line of X- and O-types. The presence of small parameters (ratio of characteristic length scales in and perpendicular to the equatorial plane and the smallness of the elect...

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Large Eddy Simulation of Sediment Transport Over Rippled Beds : Vo...

By: S. T. Grilli; J. C. Harris

Description: Department of Ocean Engineering, University of Rhode Island, Narragansett, RI, USA. Wave-induced boundary layer (BL) flows over sandy rippled bottoms are studied using a numerical model that applies a one-way coupling of a far-field inviscid flow model to a near-field large eddy simulation (LES) Navier–Stokes (NS) model. The incident inviscid velocity and pressure fields force the LES, in which near-field, wave-induced, turbulent bottom BL flows ar...

Chou, Y. J. and Fringer, O. B.: Consistent discretization for simulations of flows with moving generalized curvilinear coordinates, Int. J. Numer. Meth. Fl., 62, 802–826, 2009.; Chou, Y.-J. and Fringer, O. B.: A model for the simulation of coupled flow-bed form evolution in turbulent flows, J. Geophys. Res., 115, C10041, doi:10.1029/2010JC006103, 2010.; Chow, F. K. and Street, R. L.: Explicit filtering and reconstruction...

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A Comparison of the Performance of 4D-var in an Explicit and Impli...

By: H. A. Dijkstra; A. D. Terwisscha Van Scheltinga

Description: Institute for Marine and Atmospheric research Utrecht, Department of Physics and Astronomy, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands. A comparison is made of the performance of the four-dimensional variational data assimilation (4D-Var) method in an explicit and implicit version of a barotropic quasi-geostrophic model of the wind-driven double-gyre ocean circulation. As is well known, implicit methods have the advantage that...

Courtier, P., Thépaut, F.-N., and Hollingsworth, A.: A strategy for operational implementation of 4D-Var, using an incremental approach, Q. J. Roy. Meteor. Soc., 120, 1367–1388, 1994.; De~Niet, A., Wubs, F., Dijkstra, H., and Terwisscha~van Scheltinga, A.: A tailored solver for bifurcation analysis of high-resolution ocean models, J. Comp. Phys., 227, 654–679, 2007.; Dijkstra, H A.: Nonlinear Physical Oceanography: A Dynamical Systems Approach to the Large Scale Ocean Ci...

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An Etkf Approach for Initial State and Parameter Estimation in Ice...

By: C. Ritz; V. Peyaud; M. Nodet; B. Bonan

Description: INRIA, Laboratoire Jean Kuntzmann (LJK), Grenoble, France. Estimating the contribution of Antarctica and Greenland to sea-level rise is a hot topic in glaciology. Good estimates rely on our ability to run a precisely calibrated ice sheet evolution model starting from a reliable initial state. Data assimilation aims to provide an answer to this problem by combining the model equations with observations. In this paper we aim to study a state-of-the-art en...

Anderson, J. L. and Anderson, S. L.: A Monte Carlo implementation of the nonlinear filtering problem to produce ensemble assimilations and forecasts, Mon. Weather Rev., 127, 2741–2758, 1999.; Arthern, R. J.: Optimal estimation of changes in the mass of ice sheets, J. Geophys. Res., 108, 6007, doi:10.1029/2003JF000021, 2003.; Arthern, R. J. and Gudmundsson, G. H.: Initialization of ice-sheet forecasts viewed as an inverse...

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High Frequency Ion Sound Waves Associated with Langmuir Waves in T...

By: G. Thejappa; R. J. MacDowall

Description: Department of Astronomy, University of Maryland, College Park, MD 20742, USA. Short wavelength ion sound waves (2-4kHz) are detected in association with the Langmuir waves (~15-30kHz) in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir wave...

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Empirical Study of Multifractal Phase Transitions in Atmospheric T...

By: D. Schertzer; Y. Brunet; S. Lovejoy; F. Schmitt

Description: Laboratoire de Météorologie Dynamique (CNRS), Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05, France. We study atmospheric wind turbulence in the framework of universal multifractals, using several medium resolution (10 Hz) time series. We cut these original time series into 704 scale invariant realizations. We then compute the moment scaling exponent of the energy flux K(q) for 4 and 704 realizations, in order to study qu...

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Scaling Properties of Gravity-driven Sediments : Volume 2, Issue 3...

By: D. H. Rothman; J. P. Grotzinger

Description: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Recent field observations of the statistical distribution of turbidite and debris flow deposits are discussed. In some cases one finds a good fit over 1.5-2 orders of magnitude to the scaling law N(h) α h-B, where N(h) is the number of layers thicker than h. Observations show that the scaling ex...

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Influence of Thresholding in Mass and Entropy Dimension of 3-d Soi...

By: J. M. Antón; R. J. Heck; J. B. Grau; M. E. Sanchez; J. Fabregat; A. M. Tarquis

Description: C.E.I.G.R.A.M. E.T.S. Ing. Agrónomos (E.T.S.I.A.), Universidad Politécnica de Madrid (U.P.M.), Ciudad Universitaria, s.n. 28040 Madrid, Spain. With the advent of modern non-destructive tomography techniques, there have been many attempts to analyze 3-D pore space features mainly concentrating on soil structure. This analysis opens a challenging opportunity to develop techniques for quantifying and describe pore space properties, one of them being fractal ...

Anderson, S. H., Gantzer, C. J., Boone, J. M., and Tully, R. J.: Rapid nondestructive bulk density and soil-water content determination by computed tomography, Soil. Sci. Soc. A. J., 52, 35–40, 1988.; Anderson, A. N., McBratney, A. B., and FitzPatrick, E. A.: Soil Mass, Surface, and Spectral Fractal Dimensions Estimated from Thin Section Photographs, Soil. Sci. Soc. A. J., 60, 962–969, 1996.; Anderson, S. H., Wang, H., Peyton, R. L., and Gantzer, C. J.: Estimation of por...

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The Impact of Nonlinearity in Lagrangian Data Assimilation : Volum...

By: A. Apte; C. K. R. T. Jones

Description: TIFR Centre for Applicable Mathematics, P. O. Bag 6503, Chikkabommasandra, Bangalore 560064, India. The focus of this paper is on how two main manifestations of nonlinearity in low-dimensional systems – shear around a center fixed point (nonlinear center) and the differential divergence of trajectories passing by a saddle (nonlinear saddle) – strongly affect data assimilation. The impact is felt through their leading to non-Gaussian distribution functi...

Anderson, J. L.: An Ensemble Adjustment Kalman Filter for Data Assimilation, Mon. Weather Rev., 129, 2884, 2001.; Apte, A., Hairer, M., Stuart, A., and Voss, J.: Sampling the posterior: an approach to non-Gaussian data assimilation, Physica D, 230, 50–64, 2007.; Apte, A., Jones, C., Stuart, A., and Voss, J.: Data assimilation: Mathematical and statistical perspectives, Int. J. Numer. Meth. Fluids, 56, 1033–1046, 2008{a}.; Apte, A., Jones, C., and Stuart, A. M.: A B}ayesi...

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Finding Recurrence Networks' Threshold Adaptively for a Specific T...

By: S. Prasad; J. Kurths; N. Marwan; D. Eroglu

Description: Potsdam Institute for Climate Impact Research, Potsdam, Germany. Recurrence plot based recurrence networks are an approach to analyze time series using complex networks theory. In both approaches, recurrence plots and recurrence networks, a threshold to identify recurrent states is required. The selection of the threshold is important in order to avoid bias of the recurrence network results. In this paper we propose a novel method to choose a recurrence...

Asghari, N., Broeg, C., Carone, L., Casas-Miranda, R., Palacio, J. C. C., Csillik, I., Dvorak, R., Freistetter, F., Hadjivantsides, G., Hussmann, H., Khramova, A., Khristoforova, M., Khromova, I., Kitiashivilli, I., Kozlowski, S., Laakso, T., Laczkowski, T., Lytvinenko, D., Miloni, O., Morishima, R., Moro-Martin, A., Paksyutov, V., Pal, A., Patidar, V., Pecnik, B., Peles, O., Pyo, J., Quinn, T., Rodriguez, A., Romano, M. C., Saikia, E., Stadel, J., Thiel, M., Todorovic, ...

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Anomalous Width Variation of Rarefactive Ion Acoustic Solitary Wav...

By: S. S. Ghosh; G. S. Lakhina

Description: Indian Institute of Geomagnetism, Kalamboli, New Panvel (W), Navi Mumbai, 410 218, India. The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. Since their velocities are of the order of the ion acoustic speed, they may well be considered as being generated from the nonlinear evolution of ion acoustic waves. However, they do not show the expected width-amplitude correlation for K-dV solitons. Recent POLAR...

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Fractal Dimensions of Wildfire Spreading : Volume 21, Issue 4 (07/...

By: S.-p. Li; H.-i. Lee; S.-l. Wang

Description: Institute of Physics, Academia Sinica 128 Sec. 2, Academia Rd., Nankang, Taipei, 11529, Taiwan (ROC). The time series data of 31 wildfires in 2012 in the US were analyzed. The fractal dimensions (FD) of the wildfires during spreading were studied and their geological features were identified. A growth model based on the cellular automata method is proposed here. Numerical study was performed and is shown to give good agreement with the fractal dimensions...

Alexandridis, A., Vakalis, D., Siettos, C. I., and Bafas, G. V.: A cellular automata model for forest fire spread prediction: The case of the wildfire that swept through Spetses Island in 1990, Appl. Math. Comput., 204, 191–201, 2008.; Anderson, D. G., Catchpole, E. A., DeMestre, N. J., and Parkes, E.: Modeling the spread of grass fires, J. Austral. Math. Soc., Series B, 23, 451–466, 1982.; Bak, P., Chen, K., and Tang, C.: A forest-fire model and some thoughts on turbule...

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Multivariate Non-normally Distributed Random Variables in Climate ...

By: P. Friederichs; C. Schölzel

Description: Laboratoire des Sciences du Climat et l'Environnement (LSCE), Gif-sur-Yvette, France. Probability distributions of multivariate random variables are generally more complex compared to their univariate counterparts which is due to a possible nonlinear dependence between the random variables. One approach to this problem is the use of copulas, which have become popular over recent years, especially in fields like econometrics, finance, risk man...

Aslan, B. and Zech, G.: Comparison of different goodness-of-fit tests, ArXiv Mathematics e-prints, math/0207300, 2002.; Bardossy, A. and Li, J.: Geostatistical interpolation using copulas, Water Resour. Res., 44, W07412, doi:10.1029/2007WR006115, 2008.; Beirlant, J., Goegebeur, Y., Segers, J., and Teugels, J.: Statistics of Extremes: Theory and Applications, Wiley, 2004.; Berg, D. and Bakken, H.: A Goodness-of-fit Test for Copulae Based on the Probability Integral Transf...

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Kinetic Slow Mode-type Solitons : Volume 12, Issue 2 (11/02/2005)

By: E. Dubinin; K. Sauer; K. Baumgärtel

Description: Astrophysikalisches Institut Potsdam, Germany. One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-Β plasma (Βi=0.25) and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions (Stasiewicz et al., 2003; Stasiewicz, 2004) against kinetic theory. In the simulations, a variety of strongly obl...

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