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Observational Tests of the Properties of Turbulence in the Very Lo...

By: A. H. Savage; S. Redfield; S. R. Spangler

Description: Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA. The Very Local Interstellar Medium (VLISM) contains clouds which consist of partially-ionized plasma. These clouds can be effectively diagnosed via high resolution optical and ultraviolet spectroscopy of the absorption lines they form in the spectra of nearby stars. Information provided by these spectroscopic measurements includes values for ξ, the root-mean-square veloci...

Armstrong, J. W., Coles, W. A., Kojima, M., and Rickett, B. J.: Observations of field-aligned density fluctuations in the inner solar wind, Astrophys. J., 358, p. 685, 1990.; Bavassano, B., Dobrowolny, M., Fanfoni, G., Mariani, F., and Ness, N. F.: Statistical properties of MHD fluctuations associated with high-speed streams from Helios-2 observations, Sol. Phys., 78, p. 373, 1982.; Bird, M. K. and Edenhofer, P.: Remote sensing observations of the solar corona, in: Physi...

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Synchronicity as an Essential Property of Solar–terrestrial Relati...

By: V. A. Tartakovsky

Description: Institute of Monitoring of Climatic and Ecological Systems SB RAS, Tomsk, Russia. It is assumed that external forcing synchronizes processes initiated by it. The concept of the synchronicity of processes is defined, based on their essential signs. The processes under study are decomposed on latent orthogonal components, which differ because of the coincidence and non-coincidence of the essential signs. The information from the original da...

Lyubushin, A. A.: Analiz dannyh sistem geofizicheskogo i ekologicheskogo monitoringa, Nauka, Moskva, 2007.; Met Office Hadley Centre Observations Datasets: available at: http://www.metoffice.gov.uk/hadobs/crutem4/data/download.html, last access: 17 June 2015.; Alekseev, G. V., Luk'janova, R. Ju., and Ivanov, T. E.: Vlijanie fluktuacij i izmenenij solnechnoj aktivnosti na harakteristiki klimata vyso...

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A Study of Magnetic Fluctuations and Their Anomalous Scaling in th...

By: A. Balogh; C. Pagel

Description: The Blackett Laboratory, Imperial College, London, UK. The solar wind is a highly turbulent and intermittent medium at frequencies between 10-4 and 10-1 Hz. Power spectra are used to look at fluctuations in the components of the magnetic field at high frequencies over a wide range of latitudes. Results show steady turbulence in the polar regions of the Sun and a more varied environment in the equatorial region. The m...

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Structuring of Turbulence and Its Impact on Basic Features of Ekma...

By: S. Outten; S. Tyuryakov; I. Esau; S. Zilitinkevich; R. Davy

Description: Nansen Environmental and Remote Sensing Center, Thormohlensgt. 47, 5006 Bergen, Norway. The turbulent Ekman boundary layer (EBL) has been studied in a large number of theoretical, laboratory and modeling works since F. Nansen's observations during the Norwegian Polar Expedition 1893–1896. Nevertheless, the proposed analytical models, analysis of the EBL instabilities, and turbulence-resolving numerical simulations are not fully consistent. In particular,...

Zhang, G., Xu, X., and Wang, J.: A dynamic study of Ekman characteristics by using 1998 SCSMEX and TIPEX boundary layer data, Adv. Atmos. Sci., 30, 349–356, 2003.; Andren, A. and Moeng, C.-H.: Single-point closures in a neutrally stratified boundary layer, J. Atmos. Sci., 50, 3366–3379, 1993.; Andren, A., Brown, A. R., Graf, J., Mason, P. J., Moeng, C.-H., Nieuwstadt, F. T. N., and Schumann, U.: Large-eddy simulation of a neutrally stratified layer: A comparison of four ...

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Response of an Ocean-atmosphere Climate Model to Milankovic Forcin...

By: E. S. Posmentier

Description: Southhampton College of long Island University, Southhampton, NY 11968, USA. There is considerable evidence in support of Milankovic's theory that variations in high-latitude summer insolation caused by Earth orbital variations are the cause of the Pleistocene ice cycles. The enigmatic discrepancy between the spectra of Milankovic forcing and of Pleistocene climate variations is believed to be resolved by the slow, nonlinear response of ice sheets to cha...

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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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A Quasi-normal Scale Elimination Model of Turbulence and Its Appli...

By: V. Perov; B. Galperin; S. Sukoriansky

Description: Department of Mechanical Engineering/Perlstone Center for Aeronautical Engineering Studies,Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel. Models of planetary, atmospheric and oceanic circulation involve eddy viscosity and eddy diffusivity, KM and KH, that account for unresolved turbulent mixing and diffusion. The most sophisticated turbulent closure models used today for geophysical applications belong in ...

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Self-organized Criticality: Does it Have Anything to Do with Criti...

By: D. L. Turcotte

Description: Department of Earth and Atmospheric Sciences, Snee Hall, Cornell University, Ithaca, NY 14853, USA. Three aspects of complexity are fractals, chaos, and self-organized criticality. There are many examples of the applicability of fractals in solid-earth geophysics, such as earthquakes and landforms. Chaos is widely accepted as being applicable to a variety of geophysical phenomena, for instance, tectonics and mantle convection. Several sim...

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On the Interaction of Wind and Steep Gravity Wave Groups Using Mil...

By: C. Kharif; E. Pelinovsky; J.-p. Giovanangeli; J. Touboul

Description: Laboratoire de Sondages Electromagnétiques de l'Environnement Terrestre, Toulon, France. The interaction of wind and water wave groups is investigated theoretically and numerically. A steep wave train is generated by means of dispersive focusing, using both the linear theory and fully nonlinear equations. The linear theory is based on the Schrödinger equation while the nonlinear approach is developed numerically within the framework of the potential the...

Banner, M. I. and Song, J.-B.: On determining the onset and strength of breaking for deep water waves. part ii : Influence of wind forcing and surface shear, J. Phys. Oceanogr., 32(9), 2559–2570, 2002.; Belcher, S. E. and Hunt, J. C. R.: Turbulent flows over hill and waves, Annu. Rev. Fluid. Mech., 30, 507–538, 1998.; Benney, D. J. and Newell, A. C.: The propagation of nonlinear wave envelop, J. Math. Phys., 46, 133–139, 1967.; Brown, M. G. and Jensen, A.: Experiments on...

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Detecting Spatial Patterns with the Cumulant Function – Part 2: an...

By: P. Yiou; P. Naveau; M. Vrac; A. Bernacchia

Description: Dipartimento di Fisica, Università La Sapienza, Roma, Italy. The spatial coherence of a measured variable (e.g. temperature or pressure) is often studied to determine the regions of high variability or to find teleconnections, i.e. correlations between specific regions. While usual methods to find spatial patterns, such as Principal Components Analysis (PCA), are constrained by linear symmetries, the dependence of variables such as temperature or pressur...

Alexander, M. A., Blade, I., Newman, M., Lanzante, J. R., Lau, N. C., and Scott, J.D.: The atmospheric bridge: the influence of ENSO teleconnections on air-sea interaction over the global oceans, J. Climate, 15, 2205–2231, 2002.; Arfken, G.: The Method of Steepest Descents, in: Mathematical Methods for Physicists, 3rd Ed., Orlando, FL, Academic Press, 428–436, 1985.; Bernacchia, A. and Naveau, P.: Detecting spatial patterns with the cumulant function – Part 1: The theory...

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Intermittent Chaos Driven by Nonlinear Alfvén Waves : Volume 11, I...

By: A. J. Preto; A. C.-l. Chian; S. Stephany; E. L. Rempel

Description: National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, São José dos Campos, SP-12227-010, Brazil. We investigate the relevance of chaotic saddles and unstable periodic orbits at the onset of intermittent chaos in the phase dynamics of nonlinear Alfvén waves by using the Kuramoto-Sivashinsky (KS) equation as a model for phase dynamics. We focus on the role of nonattracting chaotic solutions o...

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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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A Chaotically Driven Model Climate: Extreme Events and Snapshot At...

By: T. Tél; Gy. Károlyi; T. Bódai

Description: Institute for Theoretical Physics, Eötvös University, Pázmány P. s. 1/A, Budapest, 1117, Hungary. In a low-order chaotic global atmospheric circulation model the effects of deterministic chaotic driving are investigated. As a result of driving, peak-over-threshold type extreme events, e.g. cyclonic activity in the model, become more extreme, with increased frequency of recurrence. When the characteristic time of the driving is comparable to that of the ...

Altmann, E. G. and Kantz, H.: Recurrence time analysis, long-term correlations, and extreme events, Phys. Rev. E, 71, 056106, doi:10.1103/PhysRevE.71.056106, 2005.; Arnold, L.: Random Dynamical Systems, Springer-Verlag, Berlin, 1998.; Blender, R., Fraedrich, K., and Sienz, F.: Extreme event return times in long-term memory processes near 1/f, Nonlin. Processes Geophys., 15, 557–565, doi:10.5194/npg-15-557-2008, 2008.;...

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Weather Regime Dependence of Extreme Value Statistics for Summer T...

By: Z. X. Li; M. Nogaj; P. Yiou; K. Goubanova

Description: Laboratoire des Sciences du Climat et de l'Environnement/IPSL, CE Saclay l'Orme des Merisiers, 91191 Gif-sur-Yvette, France. Extreme Value Theory (EVT) is a useful tool to describe the statistical properties of extreme events. Its underlying assumptions include some form of temporal stationarity in the data. Previous studies have been able to treat long-term trends in datasets, to obtain the time dependence of EVT parameters in a parametric form. Since...

Beck, C., Jacobeit, J., and Jones, P.: Frequency and within-type variations of large-scale circulation types and their effects on low-frequency climate variability in Central Europe since 1780, Int. J. Climatol., 27, 473–491, 2007.; Bernacchia, A. and Naveau, P.: Detecting spatial patterns with the cumulant function. Part I: The theory, Nonlin. Processes Geophys., 15, 159–167, 2007.; Bradley, R S.: Paleoclimatology: Reconstructing Climates of the Quaternary, Academic Pre...

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The Effect of Upstream Turbulence and Its Anisotropy on the Effici...

By: Z. Vörös; J. Šimkanin; D. Jankovičová

Description: Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic. The importance of space weather and its forecasting is growing as interest in studying geoeffective processes in the Sun – solar wind – magnetosphere – ionosphere coupled system is increasing. This paper introduces the proper selection criteria for solar wind magnetic turbulence events during duskward electric field and southward Bz dri...

Borovsky, J. E. and Funsten, H. O.: Role of solar wind turbulence in the coupling of the solar wind to the Earth's magnetosphere, J. Geophys. Res., 108(A6), 1246, doi:10.1029/2002JA009601, 2003.; Bruno, R. and Carbone, V.: The solar wind as a turbulence laboratory, Living Rev. Solar Phys., 4, 1–186, 2005.; Burlaga, L. F.: Intermittent turbulence in the solar wind, J. Geophys. Res., 96, 5847–5851, 1991.; Burlaga, L. F. and Forman, M. A.: Large-scale speed fluctuations at ...

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Fractal Trajectories in a Numerical Model of the Upper Indian Ocea...

By: S. D. Meyers; J. J. O'Brien; J. F. Magnan

Description: Mesoscale Air-Sea Interaction Group, The Florida State University, Tallahassee, FL 32303, USA. A wind-driven numerical model of the Indian Ocean is used to examine the horizontal statistics of hundreds of passive tracers spread evenly over the model domain. The distribution covers several dynamically distinct regions, revealing a variety of Lagrangian behaviours associated with different geographic locations. In particular, a cluster of trajectories with...

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Can an Ensemble Give Anything More Than Gaussian Probabilities? : ...

By: J. C. W. Denholm-price

Description: School of Mathematics, Kingston University, Kingston upon Thames, KT1 2EE, UK. Can a relatively small numerical weather prediction ensemble produce any more forecast information than can be reproduced by a Gaussian probability density function (PDF)? This question is examined using site-specific probability forecasts from the UK Met Office. These forecasts are based on the 51-member Ensemble Prediction System of the European Centre for ...

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Estimating the Diffusive Heat Flux Across a Stable Interface Force...

By: C. Staquet; J.-p. Chollet; C. Chemel

Description: NCAS-Weather, Centre for Atmospheric & Instrumentation Research, University of Hertfordshire, Hatfield, UK. Entrainment at the top of the convectively-driven boundary layer (CBL) is revisited using data from a high-resolution large-eddy simulation (LES). In the range of values of the bulk Richardson number RiB studied here (about 15–25), the entrainment process is mainly driven by the scouring of the interfacial layer (IL) by convective...

Taylor, G. I.: Diffusion by continuous movements, Proc. London Math. Soc., 20, 196–212, 1921.; Taylor, G. I.: The spectrum of turbulence, P. Roy. Soc. Lond. A Mat., 164, 476–490, 1938.; Betts, A. K.: Reply to comment on the paper {N}on-precipitating cumulus convection and its parameterization, Q. J. Roy. Meteor. Soc., 100, 469–471, 1974.; Bretherton, C. S., MacVean, M. K., Bechtold, P., Chlond, A., Cotton, W. R., Cuxart, J., Cuijpers, H., Khairoutdinov, M., Kosovic, B., ...

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Estimating Model Error Covariance Matrix Parameters in Extended Ka...

By: A. Ilin; J. Hakkarainen; A. Solonen; A. Bibov; M. Abbas

Description: Lappeenranta University of Technology, Lappeenranta, Finland. The extended Kalman filter (EKF) is a popular state estimation method for nonlinear dynamical models. The model error covariance matrix is often seen as a tuning parameter in EKF, which is often simply postulated by the user. In this paper, we study the filter likelihood technique for estimating the parameters of the model error covariance matrix. The approach is based on computing the likeli...

Dee, D. P.: On-line estimation of error covariance parameters for atmospheric data assimilation, Mon. Weather Rev., 123, 1128–1145, 2.0.CO;2>doi:10.1175/1520-0493(1995)123<1128:OLEOEC>2.0.CO;2, 1995.; Durbin, J. and Koopman, S. J.: Time series analysis by state space methods, Oxford University Press, New York, 2001.; Evensen, G.: Data assimilation: The ensemble Kalman filter, Springer, Berlin, 2007.; Do...

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Sub-inertial Modulation of Nonlinear Kelvin Waves in the Coastal Z...

By: D. V. Stepanov; V. V. Novotryasov

Description: V. I. Ilichev Pacific Oceanological Institute, Vladivostok, Russia. Observational evidence is presented for interaction between nonlinear internal Kelvin waves at the Ωt,i (where the Ωt is the semidiurnal frequency and the Ωi is the inertial frequency) and random oscillations of the background coastal current at the sub-inertial Ω frequency in the Japan/East Sea. Enhanced coastal currents at the sum Ω+ and di...

Emery, W. J. and Thomson, R. E.: Data Analysis Methods in Physical Oceanography, Pergamon Press, New York, 1997.; Filonov, A. and Novotryasov, V.: Features of the nonlinear wave spectrum in the coastal zone. Geophiys. Res. Lett., 32, L15602, doi:10.1029/2005GL023046, 2005.; Filonov, A. and Novotryasov, V.: On a spectrum of nonlinear internal waves in the oceanic coastal zone, Nonlin. Processes Geophys., 14, 757–762,

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