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Jun 30, 2018
06/18

by
Navid C. Constantinou

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"Eddy saturation" refers to a regime in which the total mass transport of an oceanic current is insensitive to the wind stress strength. Baroclinicity is currently believed to be key to the development of an eddy-saturated state. Here, we show that eddy saturation occurs in a barotropic flow over topography, without baroclinicity. We show that eddy saturation is a fundamental property of barotropic dynamics above topography. We demonstrate that the main factor controlling the...

Topics: Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1703.06594

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3.0

Jun 28, 2018
06/18

by
Niamh Cahill; Andrew C. Kemp; Benjamin P. Horton; Andrew C. Parnell

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We present a holistic Bayesian hierarchical model for reconstructing the continuous and dynamic evolution of relative sea-level (RSL) change with fully quantified uncertainty. The reconstruction is produced from biological (foraminifera) and geochemical ({\delta}13C) sea-level indicators preserved in dated cores of salt-marsh sediment. Our model is comprised of three modules: (1) A Bayesian transfer function for the calibration of foraminifera into tidal elevation, which is flexible enough to...

Topics: Statistics, Applications, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1508.02010

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Jun 29, 2018
06/18

by
Marc Wiedermann; Alexander Radebach; Jonathan F. Donges; Jürgen Kurths; Reik V. Donner

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El Ni\~no exhibits distinct Eastern Pacific (EP) and Central Pacific (CP) types which are commonly, but not always consistently, distinguished from each other by different signatures in equatorial climate variability. Here, we propose an index based on evolving climate networks to objectively discriminate between both flavors by utilizing a scalar-valued evolving climate network measure that quantifies spatial localization and dispersion in El Ni\~no's associated teleconnections. Our index...

Topics: Data Analysis, Statistics and Probability, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1604.04432

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Jun 29, 2018
06/18

by
Kevin Heng

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We present a dimensionless index that quantifies the degree of cloudiness of the atmosphere of a transiting exoplanet. Our cloudiness index is based on measuring the transit radii associated with the line center and wing of the sodium or potassium line. In deriving this index, we revisited the algebraic formulae for inferring the isothermal pressure scale height from transit measurements. We demonstrate that the formulae of Lecavelier et al. and Benneke & Seager are identical: the former is...

Topics: Earth and Planetary Astrophysics, Astrophysics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1606.07218

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Jun 28, 2018
06/18

by
Sriakr Srinath; Lisa A. Poyneer; Alexander R. Rudy; S. Mark Ammons

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We present a sample-based, autoregressive (AR) method for the generation and time evolution of atmospheric phase screens that is computationally efficient and uses a single parameter per Fourier mode to vary the power contained in the frozen flow and stochastic components. We address limitations of Fourier-based methods such as screen periodicity and low spatial frequency power content. Comparisons of adaptive optics (AO) simulator performance when fed AR phase screens and translating phase...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1512.05424

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Jun 30, 2018
06/18

by
Kazumasa Ohno; Satoshi Okuzumi

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A number of transiting exoplanets have featureless transmission spectra that might suggest the presence of clouds at high altitudes. A realistic cloud model is necessary to understand the atmospheric conditions under which such high-altitude clouds can form. In this study, we present a new cloud model that takes into account the microphysics of both condensation and coalescence. Our model provides the vertical profiles of the size and density of cloud and rain particles in an updraft for a...

Topics: Atmospheric and Oceanic Physics, Physics, Solar and Stellar Astrophysics, Astrophysics, Earth and...

Source: http://arxiv.org/abs/1701.00917

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2.0

Jun 30, 2018
06/18

by
Adam S. Candy

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Geophysical model domains typically contain irregular, complex fractal-like boundaries and physical processes that act over a wide range of scales. Constructing geographically constrained boundary-conforming spatial discretizations of these domains with flexible use of anisotropically, fully unstructured meshes is a challenge. The problem contains a wide range of scales and a relatively large, heterogeneous constraint parameter space. Approaches are commonly ad hoc, model or application...

Topics: Geophysics, Physics, Fluid Dynamics, Computing Research Repository, Computational Geometry,...

Source: http://arxiv.org/abs/1703.08491

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3.0

Jun 30, 2018
06/18

by
Aseel Farhat; Evelyn Lunasin; Edriss S. Titi

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In this paper we survey the various implementations of a new data assimilation (downscaling) algorithm based on spatial coarse mesh measurements. As a paradigm, we demonstrate the application of this algorithm to the 3D Leray-$\alpha$ subgrid scale turbulence model. Most importantly, we use this paradigm to show that it is not always necessary that one has to collect coarse mesh measurements of all the state variables, that are involved in the underlying evolutionary system, in order to recover...

Topics: Physics, Geophysics, Analysis of PDEs, Atmospheric and Oceanic Physics, Mathematics

Source: http://arxiv.org/abs/1702.01506

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3.0

Jun 28, 2018
06/18

by
Georg A. Gottwald; Karsten Peters; Laura Davies

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Observations of tropical convection from precipitation radar and the concurring large-scale atmospheric state at two locations (Darwin and Kwajalein) are used to establish effective stochastic models to parameterise subgrid-scale tropical convective activity. Two approaches are presented which rely on the assumption that tropical convection induces a stationary equilibrium distribution. In the first approach we parameterise convection variables such as convective area fraction as an...

Topics: Data Analysis, Statistics and Probability, Atmospheric and Oceanic Physics, Physics, Adaptation and...

Source: http://arxiv.org/abs/1508.03794

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Jun 27, 2018
06/18

by
Guilherme P. Castelão

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Sampling errors are inevitable when measuring the ocean; thus, to achieve a trustable set of observations requires a quality control (QC) procedure capable to detect spurious data. While manual QC by human experts minimizes errors, it is inefficient to handle large datasets and vulnerable to inconsistencies between different experts. Although automatic QC circumvents those issues, the traditional methods results in high rates of false positives. Here, I propose a novel approach to automatically...

Topics: Atmospheric and Oceanic Physics, Data Analysis, Statistics and Probability, Physics

Source: http://arxiv.org/abs/1503.02714

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Jun 28, 2018
06/18

by
Takeshi Kuroda; Alexander S. Medvedev; Erdal Yiğit; Paul Hartogh

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Global characteristics of the small-scale gravity wave (GW) field in the Martian atmosphere obtained from a high-resolution general circulation model (GCM) are presented for the first time. The simulated GW-induced temperature variances are in a good agreement with available radio occultation data in the lower atmosphere between 10 and 30 km. The model reveals a latitudinal asymmetry with stronger wave generation in the winter hemisphere, and two distinctive sources of GWs: mountainous regions...

Topics: Geophysics, Astrophysics, Atmospheric and Oceanic Physics, Earth and Planetary Astrophysics, Physics

Source: http://arxiv.org/abs/1511.00344

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3.0

Jun 28, 2018
06/18

by
Michael Tsyrulnikov; Alexander Rakitko

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A new ensemble filter that allows for the uncertainty in the prior distribution is proposed and tested. The filter relies on the conditional Gaussian distribution of the state given the model-error and predictability-error covariance matrices. The latter are treated as random matrices and updated in a hierarchical Bayes scheme along with the state. The (hyper)prior distribution of the covariance matrices is assumed to be inverse Wishart. The new Hierarchical Bayes Ensemble Filter (HBEF)...

Topics: Data Analysis, Statistics and Probability, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1509.00652

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4.0

Jun 29, 2018
06/18

by
Adrean Webb; Takuji Waseda; Wataru Fujimoto; Kazutoshi Horiuchi; Keiji Kiyomatsu; Kazuhiro Matsuda; Yasumasa Miyazawa; Sergey Varlamov; Jun Yoshikawa

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The University of Tokyo and JAMSTEC have conducted state-of-the-art wave and current resource assessments to assist with generator site identification and construction in Japan. These assessments are publicly-available and accessible via a web GIS service designed by WebBrain that utilizes TDS and GeoServer software with Leaflet libraries. The web GIS dataset contains statistical analyses of wave power, ocean and tidal current power, ocean temperature power, and other basic physical variables....

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1607.02251

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Jun 27, 2018
06/18

by
Thomas Peacock; Matthieu J. Mercier; Henri Didelle; Samuel Viboud; Thierry Dauxois

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We present the first laboratory experimental results concerning the scattering of a low-mode internal tide by a gaussian topography. Experiments performed at the Coriolis Platform in Grenoble used a recently-conceived internal wave generator as a means of producing a high-quality mode-1 wave field. The evolution of the wave field in the absence and presence of a supercritical Gaussian was studied by performing spatiotemporal modal decompositions of velocity field data obtained using Particle...

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1505.06867

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Jun 29, 2018
06/18

by
L. De Cruz; J. Demaeyer; S. Vannitsem

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This paper describes a reduced-order quasi-geostrophic coupled ocean-atmosphere model that allows for an arbitrary number of atmospheric and oceanic modes to be retained in the spectral decomposition. The modularity of this new model allows one to easily modify the model physics. Using this new model, coined "Modular Arbitrary-Order Ocean-Atmosphere Model" (maooam), we analyse the dependence of the model dynamics on the truncation level of the spectral expansion, and unveil spurious...

Topics: Fluid Dynamics, Chaotic Dynamics, Nonlinear Sciences, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1603.06755

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Jun 27, 2018
06/18

by
Pascal Marquet; Jean-François Mahfouf

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Moist-air norms and inner-products are currently used in atmospheric science for computing dry or moist singular vectors and for determining forecast errors or sensitivity to observations based on tangent linear and adjoint models. A new moist-air norm is defined starting from old results published in Marquet (QJRMS 1993) and based on the "Available Enthalpy" approach, namely one of the Exergy function defined in general thermodynamics. Some interesting and promising impacts of this...

Topics: Atmospheric and Oceanic Physics, Fluid Dynamics, Geophysics, Physics

Source: http://arxiv.org/abs/1503.01652

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0.0

Jun 30, 2018
06/18

by
Markus Gross

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Seven data sources are analyzed and combined to form a surface wind speed climatology for the Gulf of California.

Topics: Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1704.05922

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3.0

Jun 27, 2018
06/18

by
Benjamin Krank; Wolfgang A. Wall

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A novel approach to wall modeling for the incompressible Navier-Stokes equations including flows of moderate and large Reynolds numbers is presented. The basic idea is that a problem-tailored function space allows prediction of turbulent boundary layer gradients with very coarse meshes. The proposed function space consists of a standard polynomial function space plus an enrichment, which is constructed using Spalding's law-of-the-wall. The enrichment function is not enforced but...

Topics: Atmospheric and Oceanic Physics, Computational Physics, Physics, Fluid Dynamics, Mathematics,...

Source: http://arxiv.org/abs/1505.05786

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Jun 28, 2018
06/18

by
Julian Mak; James R. Maddison; David P. Marshall

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Coarse resolution numerical ocean models must typically include a parameterisation for mesoscale turbulence. A common recipe for such parameterisations is to invoke down-gradient mixing, or diffusion, of some tracer quantity, such as potential vorticity or buoyancy. However, it is well known that eddy fluxes include large rotational components which necessarily do not lead to any mixing; eddy diffusivities diagnosed from unfiltered fluxes are thus contaminated by the presence of these...

Topics: Computational Physics, Atmospheric and Oceanic Physics, Mathematics, Fluid Dynamics, Optimization...

Source: http://arxiv.org/abs/1512.04045

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2.0

Jun 27, 2018
06/18

by
Kevin Heng; Aurélien Wyttenbach; Baptiste Lavie; David K. Sing; David Ehrenreich; Christophe Lovis

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We present a theory for interpreting the sodium lines detected in transmission spectra of exoplanetary atmospheres. Previous analyses employed the isothermal approximation and dealt only with the transit radius. By recognising the absorption depth and the transit radius as being independent observables, we develop a theory for jointly interpreting both quantities, which allows us to infer the temperatures and number densities associated with the sodium lines. We are able to treat a...

Topics: Atmospheric and Oceanic Physics, Astrophysics, Physics, Earth and Planetary Astrophysics

Source: http://arxiv.org/abs/1503.05582

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1.0

Jun 26, 2018
06/18

by
Mohammadreza Aminikashani; Murat Uysal; Mohsen Kavehrad

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In this paper, we propose a new probability distribution function which accurately describes turbulence-induced fading under a wide range of turbulence conditions. The proposed model, termed Double Generalized Gamma (Double GG), is based on a doubly stochastic theory of scintillation and developed via the product of two Generalized Gamma (GG) distributions. The proposed Double GG distribution generalizes many existing turbulence channel models and provides an excellent fit to the published...

Topics: Mathematics, Computing Research Repository, Information Theory, Atmospheric and Oceanic Physics,...

Source: http://arxiv.org/abs/1502.00348

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1.0

Jun 29, 2018
06/18

by
Emil Zak; Jonathan Tennyson; Oleg L. Polyansky; Lorenzo Lodi; Nikolay F. Zobov; Sergey A. Tashkun; Valery I. Perevalov

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Atmospheric carbon dioxide concentrations are being closely monitored by remote sensing experiments which rely on knowing line intensities with an uncertainty of 0.5% or better. We report a theoretical study providing rotation-vibration line intensities substantially within the required accuracy based on the use of a highly accurate {\it ab initio} dipole moment surface (DMS). The theoretical model developed is used to compute CO$_2$ intensities with uncertainty estimates informed by cross...

Topics: Computational Physics, Chemical Physics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1601.05334

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0.0

Jun 28, 2018
06/18

by
Alice Nadeau; Richard McGehee

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Common methods for calculating a planet's annual insolation by latitude have relied on computationally heavy or complex computer algorithms. In this paper, we show that mean annual insolation by latitude of a planet with obliquity angle $\beta$ can be found by taking the definite integral of a function of longitude. This leads to faster computations and more accurate results. We discuss differences between our method and selected computational results for insolation found in the literature.

Topics: Astrophysics, Atmospheric and Oceanic Physics, Earth and Planetary Astrophysics, Physics

Source: http://arxiv.org/abs/1510.04542

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Jun 28, 2018
06/18

by
David Collins; Boualem Khouider

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We propose a mathematical methodology to derive a stochastic parameterization of bulk warm cloud micro-physics properties. Unlike previous bulk parameterizations, the stochastic parameterization does not assume any particular droplet size distribution, all parameters have physical meanings which are recoverable from data, and the resultant parameterization has the flexibility to utilize a variety of collision kernels. Our strategy is a new two-fold approach to modelling the kinetic collection...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1512.08517

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0.0

Jun 29, 2018
06/18

by
David Collins; Boualem Khouider

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The representation of clouds and associated processes of rain and snow formation remains one of the major uncertainties in climate and weather prediction models. In a companion paper (Part I), we systematically derived a two moment bulk cloud microphysics model for collision and coalescence in warm rain based on the kinetic coalescence equation (KCE) and used stochastic approximations to close the higher order moment terms, and do so independently of the collision kernel. Conservation of mass...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1605.02724

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Jun 29, 2018
06/18

by
Øyvind Breivik; Jean-Raymond Bidlot; Peter A. E. M. Janssen

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A new approximation to the Stokes drift velocity profile based on the exact solution for the Phillips spectrum is explored. The profile is compared with the monochromatic profile and the recently proposed exponential integral profile. ERA-Interim spectra and spectra from a wave buoy in the central North Sea are used to investigate the behaviour of the profile. It is found that the new profile has a much stronger gradient near the surface and lower normalized deviation from the profile computed...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1601.08092

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1.0

Jun 28, 2018
06/18

by
Francesco Ragone; Gualtiero Badin

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In this study we give a characterization of semi-geostrophic turbulence by performing freely decaying simulations for the case of constant uniform potential vorticity, a set of equations known as surface semi-geostrophic approximation. The equations are formulated as conservation laws for potential temperature and potential vorticity, with a nonlinear Monge-Amp\'{e}re type inversion equation for the streamfunction, expressed in a transformed coordinate system that follows the geostrophic flow....

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1510.07485

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Jun 29, 2018
06/18

by
Joseph G. Fitzgerald; Brian F. Farrell

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Stratified turbulence is characterized by strong anisotropy and a red energy spectrum. Moreover, in many cases the energetic large scales consist of coherent horizontal structures such as vertically sheared horizontal flows, also called stacked jets. Examples of such jets in stratified geophysical flows include the equatorial deep jets in the oceans and the quasi-biennial oscillation in the stratosphere. The mechanism responsible for the formation and maintenance of these jets in stratified...

Topics: Fluid Dynamics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1612.03243

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0.0

Jun 28, 2018
06/18

by
Philippe H. Trinh

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The standard analytical approach for studying gravity free-surface waves generated by a moving body often relies upon a linearization of the physical geometry, where the body is considered asymptotically small in one or several of its dimensions. In this paper, a methodology that avoids any such geometrical simplification is presented for the case of flows at low speeds. The approach is made possible through a reduction of the water-wave equations to a complex-valued integral equation that can...

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Complex Variables, Mathematics, Physics

Source: http://arxiv.org/abs/1510.06647

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1.0

Jun 28, 2018
06/18

by
Jinkai Li; Edriss S. Titi

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In this paper, we consider a nonlinear interaction system between the barotropic mode and the first baroclinic mode of the tropical atmosphere with moisture; that was derived in [Frierson, D.M.W.; Majda, A.J.; Pauluis, O.M.: Dynamics of precipitation fronts in the tropical atmosphere: a novel relaxation limit, Commum. Math. Sci., 2 (2004), 591-626.] We establish the global existence and uniqueness of strong solutions to this system, with initial data in $H^1$, for each fixed convective...

Topics: Atmospheric and Oceanic Physics, Geophysics, Analysis of PDEs, Physics, Fluid Dynamics, Mathematics

Source: http://arxiv.org/abs/1507.05231

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Jun 29, 2018
06/18

by
Mark J. Ablowitz; Yi-Ping Ma; Igor Rumanov

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The appearance of a fundamental long-time asymptotic regime in the two space one time dimensional hyperbolic nonlinear Schr\"odinger (HNLS) equation is discussed. Based on analytical and extensive numerical simulations an approximate self-similar solution is found for a wide range of initial conditions -- essentially for initial lumps of small to moderate energy. Even relatively large initial amplitudes, which imply strong nonlinear effects, eventually lead to local structures resembling...

Topics: Nonlinear Sciences, Atmospheric and Oceanic Physics, Physics, Mathematics, Pattern Formation and...

Source: http://arxiv.org/abs/1606.02782

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Jun 29, 2018
06/18

by
Darren Engwirda; Maxwell Kelley

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A new, high-order slope-limiting procedure for the Piecewise Parabolic Method (PPM) and the Piecewise Quartic Method (PQM) is described. Following a Weighted Essentially Non-Oscillatory (WENO)-type paradigm, the proposed slope-limiter seeks to reconstruct smooth, non-oscillatory piecewise polynomial profiles as a non-linear combination of the natural and monotone-limited PPM and PQM interpolants. Compared to existing monotone slope-limiting techniques, this new strategy is designed to improve...

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Computational Physics, Numerical Analysis,...

Source: http://arxiv.org/abs/1606.08188

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1.0

Jun 29, 2018
06/18

by
Aleš Berkopec

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Cloud-to-ground lightning is the most common among atmospheric discharges. Since electric fields in the vicinity of a thunder-cloud do not exceed 250 kV/m the physical process that triggers the lightning remains unexplained. [1, 2, 3] Recent measurements established a weak correlation between solar wind and incidence of lightning. [4] Here we show, that if an ionized path created by cosmic rays provides a trigger, the distribution of lengths between two successive forking points in a lightning...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1602.02496

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Jun 30, 2018
06/18

by
Didier Clamond; Denys Dutykh

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This paper describes an efficient algorithm for computing steady two-dimensional surface gravity wave in irrotational motion. The algorithm complexity is O(N log N), N being the number of Fourier modes. The algorithm allows the arbitrary precision computation of waves in arbitrary depth, i.e., it works efficiently for Stokes, cnoidal and solitary waves, even for quite large steepnesses. The method is based on conformal mapping, Babenko equation rewritten in a suitable way, pseudo-spectral...

Topics: Physics, Numerical Analysis, Analysis of PDEs, Atmospheric and Oceanic Physics, Classical Physics,...

Source: http://arxiv.org/abs/1702.04132

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Jun 30, 2018
06/18

by
Marsha Berger; Jonathan Goodman

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This paper examines the questions of whether smaller asteroids that burst in the air over water can generate tsunamis that could pose a threat to distant locations. Such air burst-generated tsunamis are qualitatively different than the more frequently studied earthquake-generated tsunamis, and differ as well from impact asteroids. Numerical simulations are presented using the shallow water equations in several settings, demonstrating very little tsunami threat from this scenario. A model...

Topics: Fluid Dynamics, Physics, Dynamical Systems, Atmospheric and Oceanic Physics, Mathematics

Source: http://arxiv.org/abs/1704.03552

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0.0

Jun 28, 2018
06/18

by
V. Klausner; F. C. de Meneses; C. M. N. Candido; J. R. Abalde; P. R. Fagundes; E. A. Kherani

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In this work, we present first report on disturbances over Brazilian atmosphere on 16--17 September, 2015 following the Chile tsunami occurrence. Using all-sky imager and magnetometer located at 2330 km away from the epicenter, the presence of disturbances is noted 1--3 hours after the tsunami beginning time and during time which seismic tremor was also felt in the region. We argue that their presence towards continent at 2000-3000 km away from the epicenter offers another example of similar...

Topics: Space Physics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1510.06591

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1.0

Jun 30, 2018
06/18

by
Aidan Keane; Pablo E. Olmos Aguirre; Hannah Ferchland; Peter Clive; Daniel Gallacher

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An analytical wind turbine wake model is proposed to predict the wind velocity distribution for all distances downwind of a wind turbine, including the near-wake. This wake model augments the Jensen model and subsequent derivations thereof, and is a direct generalization of that recently proposed by Bastankhah and Porte-Agel. The model is derived by applying conservation of mass and momentum in the context of actuator disk theory, and assuming a distribution of the double-Gaussian type for the...

Topics: Fluid Dynamics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1702.00166

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Jun 29, 2018
06/18

by
Juan Simarro; Petra Smolikova; Jozef Vivoda

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An analytical linear solution of the fully compressible Euler equations is found, in the particular case of a stationary two dimensional flow that passes over an orographic feature with small height-width ratio. A method based on the covariant formulation of the Euler equations is used, and the analytical vertical velocity as well as the horizontal velocity, density and pressure, are obtained. The analytical solution is tested against a numerical model in three different regimes, hydrostatic,...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1612.05673

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2.0

Jun 26, 2018
06/18

by
Alexis Tantet; Fiona R. van der Burgt; Henk A. Dijkstra

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The existence of persistent midlatitude atmospheric flow regimes with time-scales larger than 5-10 days and indications of preferred transitions between them motivates to develop early warning indicators for such regime transitions. In this paper, we use a hemispheric barotropic model together with estimates of transfer operators on a reduced phase space to develop an early warning indicator of the zonal to blocked flow transition in this model. It is shown that, the spectrum of the transfer...

Topics: Atmospheric and Oceanic Physics, Nonlinear Sciences, Chaotic Dynamics, Physics

Source: http://arxiv.org/abs/1502.00799

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2.0

Jun 26, 2018
06/18

by
Aviad Levis; Yoav Y. Schechner; Amit Aides; Anthony B. Davis

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This paper introduces a method to preform optical tomography, using 3D radiative transfer as the forward model. We use an iterative approach predicated on the Spherical Harmonics Discrete Ordinates Method (SHDOM) to solve the optimization problem in a scalable manner. We illustrate with an application in remote sensing of a cloudy atmosphere.

Topics: Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1501.06093

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2.0

Jun 28, 2018
06/18

by
Lucas Benney; Anca Radulescu

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Due to climate change, the interest of studying our climatic system using mathematical modeling has become tremendous in recent years. One well-known model is Budyko's system, which represents the coupled evolution of two variables, the ice-line and the average earth surface temperature. The system depends on natural parameters, such as the earth albedo, and the amount A of carbon in the atmosphere. We introduce a 3-dimensional extension of this model in which we regard A as the third coupled...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1512.07635

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Jun 30, 2018
06/18

by
Alberto Alberello; Amin Chabchoub; Jason Monty; Filippo Nelli; Jung Lee; John Elsnab; Alessandro Toffoli

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Nonlinear wave interactions affect the evolution of steep wave groups, their breaking and the associated kinematic field. Laboratory experiments are performed to investigate the effect of the underlying focussing mechanism on the shape of the breaking wave and its velocity field. In this regard, it is found that the shape of the wave spectrum plays a substantial role. Broader underlying wave spectra leads to energetic plungers at a relatively low amplitude. For narrower spectra waves break at a...

Topics: Pattern Formation and Solitons, Physics, Nonlinear Sciences, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1703.01043

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Jun 29, 2018
06/18

by
Cihan Bayindir

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In this paper we propose an extended Kundu-Eckhaus equation (KEE) for modeling the dynamics of skewed rogue waves emerging in the vicinity of a wave blocking point due to opposing current. The equation we propose is a KEE with an additional potential term therefore the results presented in this paper can easily be generalized to study the quantum tunneling properties of the rogue waves and ultrashort (femtosecond) pulses of the KEE. In the frame of the extended KEE, we numerically show that the...

Topics: Fluid Dynamics, Quantum Physics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1602.05339

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Jun 26, 2018
06/18

by
Luke Bennetts; Alberto Alberello; Michael Meylan; Claudio Cavaliere; Alexander Babanin; Alessandro Toffoli

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An experimental model of transmission of ocean waves by an ice floe is presented. Thin plastic plates with different material properties and thicknesses are used to model the floe. Regular incident waves with different periods and steepnesses are used, ranging from gently-sloping to storm-like conditions. A wave gauge is used to measure the water surface elevation in the lee of the floe. The depth of wave overwash on the floe is measured by a gauge in the centre of the floe's upper surface....

Topics: Atmospheric and Oceanic Physics, Physics, Fluid Dynamics

Source: http://arxiv.org/abs/1502.07010

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Jun 27, 2018
06/18

by
Pascal Marquet

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The moist-air entropy is defined in Marquet (QJRMS 2011, arXiv:1401.1097) by $\boxed{s = s_{ref} + c_{pd} \: \ln(\theta_{s})}$ in terms of two constant values ($s_{ref}$, $c_{pd}$) and a potential entropy temperature denoted by $\theta_s$. It is shown in Marquet (2011) that a quantity denoted by $({\theta}_{s})_1$ plays the role of a leading order approximation of ${\theta}_{s}$. The aim of this note is to demonstrate in a more rigorous way that $({\theta}_{s})_1$ is indeed the leading order...

Topics: Atmospheric and Oceanic Physics, Fluid Dynamics, Geophysics, Physics

Source: http://arxiv.org/abs/1503.02287

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Jun 29, 2018
06/18

by
I. G. Usoskin; G. A. Kovaltsov; L. N. Mishina; D. D. Sokoloff; J. Vaquero

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It has been recently claimed (Zolotova and Ponyavin, Solar Phys., 291, 2869, 2016, ZP16 henceforth) that a mid-latitude optical phenomenon, which took place over the city of Astrakhan in July 1670, according to Russian chronicles, was a strong aurora borealis. If this was true, it would imply a very strong or even severe geomagnetic storm during the quietest part of the Maunder minimum. However, as we argue in this article, this conclusion is erroneous and caused by a misinterpretation of the...

Topics: Earth and Planetary Astrophysics, Astrophysics, Geophysics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1612.00705

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Jun 28, 2018
06/18

by
Gregory A. Barnett; Natasha Flyer; Louis J. Wicker

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Polyharmonic spline (PHS) radial basis functions (RBFs) are used together with polynomials to create local RBF-finite-difference (RBF-FD) weights on different node layouts for spatial discretization of the compressible Navier-Stokes equations at low Mach number, relevant to atmospheric flows. Test cases are taken from the numerical weather prediction community and solved on bounded domains. Thus, attention is given on how to handle boundaries with the RBF-FD method, as well as a novel...

Topics: Atmospheric and Oceanic Physics, Computational Physics, Physics, Numerical Analysis, Mathematics

Source: http://arxiv.org/abs/1509.02615

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Jun 28, 2018
06/18

by
Kaitlin Hill; Dorian S. Abbot; Mary Silber

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As Arctic sea ice extent decreases with increasing greenhouse gases, there is a growing interest in whether there could be a bifurcation associated with its loss, and whether there is significant hysteresis associated with that bifurcation. A challenge in answering this question is that the bifurcation behavior of certain Arctic energy balance models have been shown to be sensitive to how ice-albedo feedback is parameterized. We analyze an Arctic energy balance model in the limit as a smoothing...

Topics: Atmospheric and Oceanic Physics, Dynamical Systems, Mathematics, Physics

Source: http://arxiv.org/abs/1509.00059

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Jun 29, 2018
06/18

by
H. Boerner

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This report uses a few well documented cases of Ball Lightning (or BL for short) observations to demonstrate a correlation between BL and positive lightning, especially strong positive lightning. This allows to draw conclusions and predictions about future BL observations and the pro- duction of these objects in the laboratory. Contrary to many current BL theories, these objects can be created without direct contact to a lightning channel. Very high electric fields appear to be essential for...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1606.04421

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Jun 29, 2018
06/18

by
Markus Gross

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Mesoscale forecasts are now routinely performed as elements of operational forecasts and their outputs do appear convincing. However, despite their realistic appearance at times the comparison to observations is less favorable. At the grid scale these forecasts often do not compare well with observations. This is partly due to the chaotic system underlying the weather. Another key problem is that it is impossible to evaluate the risk of making decisions based on these forecasts because they do...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1610.07676