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Hilbert Problems for the Geosciences in the 21St Century : Volume ...

By: M. Ghil

Description: Dept. of Atmospheric Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1565, USA. The scientific problems posed by the Earth's fluid envelope, and its atmosphere, oceans, and the land surface that interacts with them are central to major socio-economic and political concerns as we move into the 21st century. It is natural, therefore, that a certain impatience should prevail in atte...

Particle-in-cell Simulations of a Lens on an F-plane : Volume 4, I...

By: C. E. Grosch; J. J. Holdzkom II.; A. D. Kirwan, Jr.

Description: Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, Virginia, 23529 USA. A particle-in-cell ansatz for solving the Euler equations in a rotating frame is described. The approach is ideally suited for layered models of flows with sharp density and velocity fronts. The material and Coriolis accelerations in the Euler equations are solved at each particle while the gradient accelerations are evaluated on a grid and interpolated at e...

Diagnostics of Solar Flare Reconnection : Volume 11, Issue 4 (01/1...

By: M. Bárta; M. Karlický

Description: Astronomical Institute, Academy of Sciences of the Czech Republic, 251 65 Ondřejov, Czech Republic. We present new diagnostics of the solar flare reconnection, mainly based on the plasma radio emission. We propose that the high-frequency (600-2000 MHz) slowly drifting pulsating structures map the flare magnetic field reconnection. These structures correspond to the radio emission from plasmoids which are formed in the extended current sheet due to tearin...

Inhomogeneous Dominance Patterns of Competing Phytoplankton Groups...

By: U. Feudel; D. Bastine

Description: Institute for Chemistry and Biology of the Marine Environment, Theoretical Physics/Complex Systems, Carl von Ossietzky University Oldenburg, Germany. We investigate the competition between two different functional groups of phytoplankton in the wake of an island close to a coastal upwelling region. We couple a simple biological model with three trophic levels and a hydrodynamic model of a von Kármán vortex street. The spatio-temporal abundance shows that...

Abraham, E. R.: The generation of plankton patchiness by turbulent stirring, Nature, 391, 577–580, 1998.; Aristegui, J., Tett, P., Hernández-Guerra, A., Basterretxea, G., Montero, M. F., Wild, K., Sangra, P., Hernández-Leon, S., Canton, M., Garc\'ia-Braun, J. A., Pacheco, M., and Barton, E. D.: The influence of island-generated eddies on chlorophyll distribution: A study of mesoscale variation around Gran Canaria, Deep-Sea Res. Part I-Oceanographic Research Papers, 44, 7...

Localized Alfvénic Solutions of Nondissipative and Compressible Mh...

By: G. Chanteur

Description: Centre d'étude des Environnments Terrestre et Planetéaires, Vélizy, France. Alfvénic solutions of nondissipative MHD are entirely determined by their magnetic configuration. With the supplementary assumption of incompressibility any solenoidal field can be used to construct an Alfvénic solution. It is demonstrated that for nondissipative and compressible MHD the energy equation constrains the magnetic field of Alfvénic solutions to have a constant stren...

Obliquely Propagating Electron Acoustic Solitons in Magnetized Pla...

By: H. R. Pakzad; K. Javidan

Description: Department of Physics, Bojnourd Branch, Islamic Azad University, Bojnourd, Iran. The problem of small amplitude electron-acoustic solitary waves (EASWs) is discussed using the reductive perturbation theory in magnetized plasmas consisting of cold electrons, hot electrons obeying nonextensive distribution and stationary ions. The presented investigation shows that the presence of nonextensive distributed hot electrons (due to the effects of long-range in...

Mamun, A. A., Shukla, P. K., and Stenflo, L.: Obliquely propagating electron-acoustic solitary waves, Phys. Plasmas, 9, 4 pp., doi:10.1063/1.1462635, 2002.; Amour, R. and Tribeche, M.: Variable charge dust acoustic solitary waves in a dusty plasma with a q-nonextensive electron velocity distribution, Phys. Plasmas, 7 pp., doi:10.1063/1.3428538, 2010.; Anowar, M. G. M. and Mamun, A. A.: Multidimensional instability of electron-acoustic solitary waves in a magnetized plasm...

A Mechanistic Modelling and Data Assimilation Approach to Estimate...

By: M. Lévy; O. Bernard; A. Sciandra; B. Faugeras

Description: Institut de Recherche pour le Développement (IRD), Sète, France. The principal objective of hydrodynamical-biological models is to provide estimates of the main carbon fluxes such as total and export oceanic production. These models are nitrogen based, that is to say that the variables are expressed in terms of their nitrogen content. Moreover models are calibrated using chlorophyll data sets. Therefore carbon to chlorophyll (C:Chl) and carbon to nitrogen...

Vertical Mixing and Coherent Anticyclones in the Ocean: the Role o...

By: A. Bracco; I. Koszalka; L. Ceballos

Description: Institute of Geosciences, University of Oslo, 1022 Blinden, 0315 Oslo, Norway. The role played by wind-forced anticyclones in the vertical transport and mixing at the ocean mesoscale is investigated with a primitive-equation numerical model in an idealized configuration. The focus of this work is to determine how the stratification impacts such transport.

The flows, forced only at the surface by an idealized wind forcing, are predominantly hor...

Arai, M. and Yamagata, T.: Asymmetric evolution of eddies in rotation shallow water, Chaos, 4, 163–173, 1994.; Arbic, B. K., Flierl, G. R., and Scott, R. B.: Cascade inequalities for forced-dissipated geostrophic turbulence, J. Phys. Oceanogr., 37, 1470–2177, 2007.; Babiano, A. and Provenzale, A.: Coherent vortices and tracer cascades in two-dimensional turbulence, J. Fluid Mech., 574, 429–448, 2007.; Bracco, A. and Pedlosky, J.: Vortex generation by topography in locall...

A Spectral Model for Turbulence and Microphysics Dynamics in an Ic...

By: A. J. Palmer

Description: NOAA, Environmental Technology Laboratory, 325 Broadway, Boulder, CO 80303, USA. A one-dimensional, nine-mode spectral model for temperature, velocity, and the mixing ratios of suspended and precipitating ice-particle components is shown to be consistent with ice-cloud observations. The observations include Doppler radar time-series measurements of a single winter ice cloud and direct measurements of mean particl...

Consequences of Entropy Bifurcation in Non-maxwellian Astrophysica...

By: M. P. Leubner

Description: Institute for Astro- and Particle Physics, University of Innsbruck, Innsbruck, Austria. Non-extensive systems, accounting for long-range interactions and correlations, are fundamentally related to non-Maxwellian distributions where a duality of equilibria appears in two families, the non-extensive thermodynamic equilibria and the kinetic equilibria. Both states emerge out of particular entropy generalization leading to a class of probability distributio...

Bruno, R., Carbone, V., Veltri, P., Pietropaolo, E., and Bavassano, B.: Identifying intermittency events in the solar wind, Planetary Space Sci., 49, 1201, 2001.; Bruno R. and Carbone, V.: The Solar Wind as a Turbulence Laboratory, Living Rev. Solar Phys., 2, 1,2005.; Burkert, A.: The Structure of Dark Matter Halos in Dwarf Galaxies, Astrophys. J., 447, L25, 1995.; Burlaga, L. F.: Multifractal structure of speed fluctuations in recurrent streams at 1 AU and near 6 AU, Ge...

Using Magnetic Fluids to Simulate Convection in a Central Force Fi...

By: W.-g. Früh

Description: School of Engineering and Physical Sciences, Heriot Watt University, Riccarton, Edinburgh, EH14 4AS, UK. Large-scale convection in planetary or stellar interiors plays a significant role but it is difficult to reproduce the central force field of those systems in experimental studies. A technique to approximate a central force field through the magnetic field from magnets acting on a magnetic liquid is presented. The thermomagnetic convection in a spheri...

Representation of Model Error in a Convective-scale Ensemble Predi...

By: R. N. Bannister; S. Migliorini; A. C. Rudd; L. H. Baker

Description: Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading, RG6 6BB, UK. In this paper ensembles of forecasts (of up to six hours) are studied from a convection-permitting model with a representation of model error due to unresolved processes. The ensemble prediction system (EPS) used is an experimental convection-permitting version of the UK Met Office's 24-member Global and Regional Ensemble Prediction System (MOGREPS). The me...

Berner, J., Shutts, G. J., Leutbecher, M., and Palmer, T. N.: A spectral stochastic kinetic energy backscatter scheme and its impact on flow-dependent predictability in the ECMWF Ensemble Prediction System, J. Atmos. Sci., 66, 603–629, 2009.; Berner, J., Ha, S.-Y., Hacker, J. P., Fournier, A., and Snyder, C.: Model uncertainty in a mesoscale ensemble prediction system: Stochastic versus multiphysics representations, Mon. Weather Rev., 139, 1972–1995, 2011.; Bishop, C. H....

A Delay Differential Model of Enso Variability – Part 2: Phase Loc...

By: M. Ghil; I. Zaliapin

Description: Department of Mathematics and Statistics, University of Nevada, Reno, Nevada, USA. We consider a highly idealized model for El Niño/Southern Oscillation (ENSO) variability, as introduced in an earlier paper. The model is governed by a delay differential equation for sea-surface temperature T in the Tropical Pacific, and it combines two key mechanisms that participate in ENSO dynamics: delayed negative feedback and seasonal forcing. We perform a t...

Battisti, D. S.: The dynamics and thermodynamics of a warming event in a coupled tropical atmosphere/ocean model, J. Atmos. Sci., 45, 2889–2919, 1988.; Battisti, D. S. and Hirst, A. C.: Interannual variability in the tropical atmosphere-ocean system: Influence of the basic state and ocean geometry, J. Atmos. Sci., 46, 1687–1712, 1989.; Bjerknes, J.: Atmospheric teleconnections from the equatorial Pacific, Mon. Weather Rev., 97, 163–172, 1969.; Burgers, G. and Stephenson,...

A Tri-stage Cluster Identification Model for Accurate Analysis of ...

By: G. Panda; K. F. Tiampo; A. Mignan; L. Mansinha; N. Cho; S. J. Nanda

Description: School of Electrical Sciences, Indian Institute of Technology Bhubaneswar, Orissa, 751013, India. In this paper we propose a tri-stage cluster identification model that is a combination of a simple single iteration distance algorithm and an iterative K-means algorithm. In this study of earthquake seismicity, the model considers event location, time and magnitude information from earthquake catalog data to efficiently classify events as either background ...

Advanced National Seismic System: available at: http://www.ncedc.org/anss/catalog-search.html, last access: 15 August 2012.; Baiesi, M. and Paczuski M.: Scale-free networks of earthquakes and aftershocks, Phys. Rev., 1–7, doi:10.1103/PhysRevE.69.066106, 2004.; Bansal, A. R. and Ogata, Y.: Seismicity activation before the mega-earthquake of 26 December 2004 b...

Numerical Wind Wave Model with a Dynamic Boundary Layer : Volume 9...

By: F. A. Pogarskii; Y. A. Volkov; V. G. Polnikov

Description: A. M. Obukhov Institute for Atmospheric Physics of the Russian Academy of Sciences, Pyzhevskii lane, 3, 109017 Moscow, Russia. A modern version of a numerical wind wave model of the fourth generation is constructed for a case of deep water. The following specific terms of the model source function are used: (a) a new analytic parameterization of the nonlinear evolution term proposed recently in Zakharov and Pushkarev (1999); (b) a traditi...

Null Modes Effect in Rossby Wave Model : Volume 11, Issue 3 (28/05...

By: V. Pavlov; V. Goncharov

Description: Radio Science Center for Space and Atmosphere (RASC), Kyoto University Gokasho, Uji, Kyoto 611-0011, Japan. The problem of the null-modes existence and some particularities of their interaction with nonlinear vortex-wave-like structures is discussed. We show that the null-modes are fundamental elements of nonlinear wave fields. The conditions under which null-modes can manifest themselves are elucidated. The Rossby-Hasegawa-Mima (RHM) model is used for ...

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...

One-dimensional Modelling of Upper Ocean Mixing by Turbulence Due ...

By: M. Ghantous; A. V. Babanin

Description: Swinburne University of Technology, Hawthorn, Victoria, Australia. Mixing of the upper ocean affects the sea surface temperature by bringing deeper, colder water to the surface. Because even small changes in the surface temperature can have a large impact on weather and climate, accurately determining the rate of mixing is of central importance for forecasting. Although there are several mixing mechanisms, one that has until recently been overlooked is ...

Anis, A. and Moum, J. N.: Surface wave-turbulence interactions: scaling $\epsilon(z)$ near the sea surface, J. Phys. Oceanogr., 25, 2025–2045, 1995.; Ardhuin, F. and Jenkins, A. D.: On the Interaction of Surface Waves and Upper Ocean Turbulence, J. Phys. Oceanogr., 36, 551–557, 2006.; Babanin, A.: Breaking and Dissipation of Ocean Surface Waves, Cambridge University Press, 2011.; Ardhuin, F., Chapron, B., and Collard, F.: Observation of swell dissipation across oceans, G...

A Method to Calculate Finite-time Lyapunov Exponents for Inertial ...

By: D. Garaboa; V. Pérez-muñuzuri

Description: Group of Nonlinear Physics, Faculty of Physics, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain. The present study aims to improve the calculus of Finite-Time Lyapunov Exponents (iFTLEs) applied to describe the transport of inertial particles in a fluid flow. To this aim, the deformation tensor used to obtain the iFTLE is modified to take into account that the stretching rate between particles separated by a certain ...

Babiano, A., Cartwright, H. H. E., Piro, O., and Provenzale, A. Dynamics of a small neutrally buoyant sphere in a fluid and targeting in Hamiltonian systems, Phys. Rev. Lett., 84, 5764–5767, 2000.; Bec, J.: Fractal clustering of inertial particles in random flows, Phys. Fluids 15, L81–L84, 2003.; Beron-Vera, F. J., Olascoaga, M. J., Haller, G., Farazmand, M., Triñanes, J., and Wang, Y.: Dissipative inertial transport patterns near coherent Lagrangian eddies in the ocean,...

A Simplified Model of the Martian Atmosphere - Part 2: a Pod-galer...

By: I. M. Moroz; S. R. Lewis; P. L. Read; S. G. Whitehouse

Description: Mathematical Institute, University of Oxford, UK. In Part I of this study Whitehouse et al. (2005) performed a diagnostic analysis of a simplied model of the Martian atmosphere, in which topography was absent and in which heating was modelled as Newtonian relaxation towards a zonally symmetric equilibrium temperature field. There we derived a reduced-order approximation to the vertical and the horizonal structure of the baroclinically unstable Martian ...

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