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Jun 26, 2018
06/18

by
Ashwin K. Seshadri

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Carbon-dioxide (CO2) is the main contributor to anthropogenic global warming, and the timing of its peak concentration in the atmosphere is likely to govern the timing of maximum radiative forcing. It is well-known that dynamics of atmospheric CO2 is governed by multiple time-constants, and here we approximate the solutions to a linear model of atmospheric CO2 dynamics with four time-constants to identify factors governing the time-delay between peaks in CO2 emissions and concentrations, and...

Topics: Atmospheric and Oceanic Physics, Physics, Physics and Society

Source: http://arxiv.org/abs/1502.00805

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Jun 30, 2018
06/18

by
Nishant K. Singh; Axel Brandenburg; Matthias Rheinhardt

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We show that in the presence of a harmonically varying magnetic field the fundamental or $f$-mode in a stratified layer is altered in such a way that it fans out in the diagnostic $k\omega$ diagram, but with mode power also within the fan. In our simulations, the surface is defined by a temperature and density jump in a piecewise isothermal layer. Unlike our previous work (Singh et al. 2014) where a uniform magnetic field was considered, we employ here a nonuniform magnetic field together with...

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

Source: http://arxiv.org/abs/1407.0356

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Jun 30, 2018
06/18

by
Sander Wildeman; Sebastian Sterl; Chao Sun; Detlef Lohse

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A drop of water that freezes from the outside-in presents an intriguing problem: the expansion of water upon freezing is incompatible with the self-confinement by a rigid ice shell. Using high-speed imaging we show that this conundrum is resolved through an intermittent fracturing of the brittle ice shell and cavitation in the enclosed liquid, culminating in an explosion of the partially frozen droplet. We propose a basic model to elucidate the interplay between a steady build-up of stresses...

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

Source: http://arxiv.org/abs/1701.06818

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Jun 29, 2018
06/18

by
Erica Rosenblum; Ian Eisenman

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The downward trend in Arctic sea ice extent is one of the most dramatic signals of climate change during recent decades. Comprehensive climate models have struggled to reproduce this, typically simulating a slower rate of sea ice retreat than has been observed. However, this bias has been widely noted to have decreased in models participating in the most recent phase of the Coupled Model Intercomparison Project (CMIP5) compared with the previous generation of models (CMIP3). Here we examine...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1605.07698

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Jun 30, 2018
06/18

by
Peng Shi; Shi-Cheng Zhao; Wen-Dong Li; Yong-Jian Gu

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We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater...

Topics: Quantum Physics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1402.4666

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Jun 30, 2018
06/18

by
Juliette Voyez; Clélia Robert; Jean-Marc Conan; Laurent M. Mugnier; Etienne Samain; Aziz Ziad

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COupled SLope and scIntillation Detection And Ranging (CO-SLIDAR) is a recent profiling method of the vertical distribution of atmospheric turbulence strength ($C_n^2$ profile). It takes advantage of correlations of slopes and of scintillation, both measured with a Shack-Hartmann wavefront sensor on a binary star. In this paper, we present the improved CO-SLIDAR reconstruction method of the $C_n^2$ profile and the first on-sky results of the CO-SLIDAR profiler. We examine CO-SLIDAR latest...

Topics: Physics, Instrumentation and Methods for Astrophysics, Atmospheric and Oceanic Physics, Astrophysics

Source: http://arxiv.org/abs/1402.4295

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Jun 30, 2018
06/18

by
Enrico Ser-Giacomi; Vincent Rossi; Cristobal Lopez; Emilio Hernandez-Garcia

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We represent transport between different regions of a fluid domain by flow networks, constructed from the discrete representation of the Perron-Frobenius or transfer operator associated to the fluid advection dynamics. The procedure is useful to analyze fluid dynamics in geophysical contexts, as illustrated by the construction of a flow network associated to the surface circulation in the Mediterranean sea. We use network-theory tools to analyze the flow network and gain insights into transport...

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

Source: http://arxiv.org/abs/1409.4171

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Jun 29, 2018
06/18

by
M. Alamgir Hossain; Jahrul M Alam

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Urbanization is one of the extreme process that increases uncertainty in future climate projections. Flow regimes of mesoscale circulations associated with surface heating due to urbanization have been investigated using a wavelet based computational fluid dynamics~(CFD) model. The results of our numerical model have been validated against that of a laboratory model, as well as reference numerical simulations. Characteristics of urban induced circulations have been studied for surface heat flux...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1611.08912

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Jun 27, 2018
06/18

by
Luca Bonaventura; Roberto Ferretti

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A semi-Lagrangian method for parabolic problems is proposed, that extends previous work by the authors to achieve a fully conservative, flux-form discretization of linear and nonlinear diffusion equations. A basic consistency and convergence analysis are proposed. Numerical examples validate the proposed method and display its potential for consistent semi-Lagrangian discretization of advection--diffusion and nonlinear parabolic problems.

Topics: Atmospheric and Oceanic Physics, Computational Engineering, Finance, and Science, Physics,...

Source: http://arxiv.org/abs/1505.00940

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Jun 30, 2018
06/18

by
Niklas Brännström; Leif Å Persson

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Footprint analysis, also known as the study of Influence areas, is a first order method for solving inverse atmospheric dispersion problems. We revisit the concept of footprints giving a rigorous definition of the concept (denoted posterior footprints and posterior zero footprints) in terms of spatio-temporal domains. The notion of footprints is then augmented the to the forward dispersion problem by defining prior footprints and prior zero footprints. We then study how posterior footprints and...

Topics: Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1409.5419

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Jun 29, 2018
06/18

by
Vassilios Dallas; Steve Tobias

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The effects of large scale mechanical forcing on the dynamics of rotating turbulent flows are studied by means of numerical simulations, varying systematically the nature of the mechanical force in time. We demonstrate that the statistically stationary solutions of these flows depend on the nature of the forcing mechanism. Rapidly enough rotating flows with a forcing that has a persistent direction relatively to the axis of rotation bifurcate from a non-helical state to a helical state despite...

Topics: Fluid Dynamics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1601.04310

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Jun 29, 2018
06/18

by
Ji Nie; Daniel A. Shaevitz; Adam H. Sobel

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Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent and large latent heat release. The causal relationships between these factors are often not obvious, however, and the roles of different physical processes in producing the extreme precipitation event can be difficult to disentangle. Here, we examine the large-scale forcings and convective heating feedback in the precipitation events which caused the 2010 Pakistan flood within the...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1603.01218

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Jun 27, 2018
06/18

by
Franck Lascaux; Elena Masciadri; Luca Fini

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This article aims at proving the feasibility of the forecast of all the most relevant classical atmospherical parameters for astronomical applications (wind speed and direction, temperature) above the ESO ground-base site of Cerro Paranal with a mesoscale atmospherical model called Meso-Nh. In a precedent paper we have preliminarily treated the model performances obtained in reconstructing some key atmospherical parameters in the surface layer 0-30~m studying the bias and the RMSE on a...

Topics: Atmospheric and Oceanic Physics, Instrumentation and Methods for Astrophysics, Astrophysics, Physics

Source: http://arxiv.org/abs/1504.01525

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Jun 30, 2018
06/18

by
Alessio Turchi; Elena Masciadri; Luca Fini

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In this paper we quantify the performances of an automated weather forecast system implemented on the Large Binocular Telescope (LBT) site at Mt. Graham (Arizona) in forecasting the main atmospheric parameters close to the ground. The system employs a mesoscale non-hydrostatic numerical model (Meso-Nh). To validate the model we compare the forecasts of wind speed, wind direction, temperature and relative humidity close to the ground with the respective values measured by instrumentation...

Topics: Atmospheric and Oceanic Physics, Physics, Instrumentation and Methods for Astrophysics, Astrophysics

Source: http://arxiv.org/abs/1701.07341

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Jun 29, 2018
06/18

by
Alessio Turchi; Elena Masciadri; Luca Fini

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In this paper we study the abilities of an atmospherical mesoscale model in forecasting the classical atmospherical parameters relevant for astronomical applications at the surface layer (wind speed, wind direction, temperature, relative humidity) on the Large Binocular Telescope (LBT) site - Mount Graham, Arizona. The study is carried out in the framework of the ALTA project aiming at implementing an automated system for the forecasts of atmospherical parameters (Meso-Nh code) and the optical...

Topics: Astrophysics, Instrumentation and Methods for Astrophysics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1609.00237

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Jun 27, 2018
06/18

by
Navid C. Constantinou

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This thesis presents a newly developed theory for the formation and maintenance of eddy-driven jets in planetary turbulence. The novelty is that jet formation and maintenance is studied as a dynamics of the statistics of the flow rather than a dynamics of individual realizations. This is pursued using Stochastic Structural Stability Theory (S3T) which studies the closed dynamics of the first two cumulants of the full statistical state dynamics of the flow after neglecting or parameterizing...

Topics: Atmospheric and Oceanic Physics, Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1503.07644

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Jun 28, 2018
06/18

by
Pascal Marquet; Jean-François Geleyn

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Internal energy, enthalpy and entropy are the key quantities to study thermodynamic properties of the moist atmosphere, because they correspond to the First (internal energy and enthalpy) and Second (entropy) Laws of thermodynamics. The aim of this chapter is to search for analytical formulas for the specific values of enthalpy and entropy and for the moist-air mixture composing the atmosphere. The Third Law of thermodynamics leads to the definition of absolute reference values for thermal...

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

Source: http://arxiv.org/abs/1510.03239

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Jun 30, 2018
06/18

by
Satish Kumar; Manfred Cuntz; Zdzislaw E. Musielak

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The rise of oxygen in Earth's atmosphere that occurred 2.4 to 2.2 billion years ago is known as the Earth's Great Oxidation, and its impact on the development of life on Earth has been profound. Thereafter, the increase in Earth's oxygen level persisted, though at a more gradual pace. The proposed underlying mathematical models for these processes are based on physical parameters whose values are currently not well-established owing to uncertainties in geological and biological data. In this...

Topics: Physics, Nonlinear Sciences, Astrophysics, Chaotic Dynamics, Atmospheric and Oceanic Physics, Earth...

Source: http://arxiv.org/abs/1402.3243

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Jun 30, 2018
06/18

by
A. G. O. Goulart; M. J. Lazo; J. M. S. Suarez; D. M. Moreira

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In the present work, we investigate the potential of fractional derivatives to model atmospheric dispersion of pollutants. We propose simple fractional differential equation models for the steady state spatial distribution of concentration of a non-reactive pollutant in Planetary Boundary Layer. We solve these models and we compare the solutions with a real experiment. We found that the fractional derivative models perform far better than the traditional Gaussian model and even better than...

Topics: Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1702.06345

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Jun 30, 2018
06/18

by
Yuri S. Djikaev; Eli Ruckenstein

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Using the formalism of the classical nucleation theory, we derive an expression for the reversible work $W_*$ of formation of a binary crystal nucleus in a liquid binary solution of non-stoichiometric composition (incongruent crystallization). Applied to the crystallization of aqueous nitric acid (NA) droplets, the new expression more adequately takes account of the effect of nitric acid vapor compared to the conventional expression of MacKenzie, Kulmala, Laaksonen, and Vesala (MKLV)...

Topics: Physics, Chemical Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1702.02500

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Jun 29, 2018
06/18

by
J. D. Carter; A. Govan

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In this paper, we derive a viscous generalization of the Dysthe (1979) system from the weakly viscous generalization of the Euler equations introduced by Dias, Dyachenko, and Zakharov (2008). This "viscous Dysthe" system models the evolution of a weakly viscous, nearly monochromatic wave train on deep water. It contains a term which provides a mechanism for frequency downshifting in the absence of wind and wave breaking. The equation does not preserve the spectral mean. Numerical...

Topics: Pattern Formation and Solitons, Fluid Dynamics, Nonlinear Sciences, Physics, Atmospheric and...

Source: http://arxiv.org/abs/1601.03932