The deployment of a High Energy Laser (HEL) weapon in an airborne platform is a challenging task due to size, weight, and power (SWaP) constraints. Recent technology innovations, however, promise that such HEL development may be a reality in the near future. This study models an Unmanned Combat Aerial Vehicle (UCAV) armed with a HEL weapon and simulates the laser beam's atmospheric propagation. The Design of Experiments (DOE) methodology is then applied to determine the significance of the...

Topics: directed energy weapons, high energy lasers, atmospheric propagation, unmanned combat aerial...

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4.0

Jun 29, 2018
06/18

by
Jacob Haqq-Misra; Prabal Saxena; Eric T. Wolf; Ravi Kumar Kopparapu

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The population of known extrasolar planets includes giant and terrestrial planets that closely orbit their host star. Such planets experience significant tidal distortions that can force the planet into synchronous rotation. The combined effects of tidal deformation and centripetal acceleration induces significant asphericity in the shape of these planets, compared to the mild oblateness of Earth, with maximum gravitational acceleration at the poles. Here we show that this latitudinal variation...

Topics: Earth and Planetary Astrophysics, Astrophysics, Instrumentation and Methods for Astrophysics,...

Source: http://arxiv.org/abs/1608.02536

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4.0

Jun 29, 2018
06/18

by
Michael Nauenberg

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Calculations of atmospheric refraction are generally based on a simplified model of atmospheric density in the troposphere which assumes that the temperature decreases at a constant lapse rate from sea level up to a height equal to eleven km, and that afterwards it remains constant. In this model, the temperature divided by the lapse rate determines the length scale in the calculations for altitudes less than this height. But daily balloon measurements across the U.S.A. reveal that in some...

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

Source: http://arxiv.org/abs/1609.08921

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4.0

Jun 29, 2018
06/18

by
David Lannes

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This paper addresses the floating body problem which consists in studying the interaction of surface water waves with a floating body. We propose a new formulation of the water waves problem that can easily be generalized in order to take into account the presence of a floating body. The resulting equations have a compressible-incompressible structure in which the interior pressure exerted by the fluid on the floating body is a Lagrange multiplier that can be determined through the resolution...

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

Source: http://arxiv.org/abs/1609.06136

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3.0

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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3.0

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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3.0

Jun 29, 2018
06/18

by
Nicola Scafetta; Franco Milani; Antonio Bianchini; Sergio Ortolani

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An oscillation with a period of about 2100-2500 years, the Hallstatt cycle, is found in cosmogenic radioisotopes (C-14 and Be-10) and in paleoclimate records throughout the Holocene. Herein we demonstrate the astronomical origin of this cycle. Namely, this oscillation is coherent to the major stable resonance involving the four Jovian planets - Jupiter, Saturn, Uranus and Neptune - whose period is p=2318 yr. The Hallstatt cycle could derive from the rhythmic variation of the circularity of the...

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

Source: http://arxiv.org/abs/1610.03096

The United States Navy's interest in high-energy lasers (HELs) dictates the need for further study into the propagation of laser light through different atmospheric conditions. Due to the amount of energy required to power these laser weapons systems and the limited amount of available energy onboard ships, different energy storage systems need to be explored. For this research, two locations were studied: the coast of Cuba and the coast of Russia. These two locations were studied during...

Topics: energy storage, lithium-ion batteries, lead acid batteries, atmospheric propagation, laser, ANCHOR

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2.0

Jun 29, 2018
06/18

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

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Devastating floods in northeast Pakistan and northern India occurred in July 2010 and September 2014 as a consequence of extreme precipitation events. The 2010 and 2014 flood events had similar synoptic flow patterns that led to an anomalously high moisture content in the flood region. The quasi-geostrophic omega equation is inverted in order to attribute components of the large-scale vertical motion profile to synoptic forcing, diabatic heating, and mechanically forced orographic ascent. The...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1603.01317

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2.0

Jun 29, 2018
06/18

by
Omer San

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A single-layer, quasi-geostrophic (QG), large-scale ocean circulation model is developed in this paper to study available ocean current energy potentials harnessed by using the ocean current turbines. Power extraction is modeled by adding a parameterized Rayleigh friction term in the barotropic vorticity equation. Numerical assessments are performed by simulating a set of mid-latitude ocean basins in the beta plane, which are standard prototypes of more realistic ocean dynamics considering...

Topics: Fluid Dynamics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1604.08486

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Jun 29, 2018
06/18

by
Georg A. Gottwald; Daan T. Crommelin; Christian L. E. Franzke

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In this chapter we review stochastic modelling methods in climate science. First we provide a conceptual framework for stochastic modelling of deterministic dynamical systems based on the Mori-Zwanzig formalism. The Mori-Zwanzig equations contain a Markov term, a memory term and a term suggestive of stochastic noise. Within this framework we express standard model reduction methods such as averaging and homogenization which eliminate the memory term. We further discuss ways to deal with the...

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

Source: http://arxiv.org/abs/1612.07474

To facilitate the study of engagement scenarios with high energy lasers, the Directed Energy Physics Group at the Naval Postgraduate School developed a laser performance code called Atmospheric NPS Code for HEL Optical pRopagation (ANCHOR). This code uses well-known analytical scaling laws and a scriptable user interface to allow the quick exploration of multi-dimensional parameter studies. Recently, a new capability was added that incorporates relative platform / target motion. This study...

Topics: directed energy weapons, high energy lasers, atmospheric propagation, relative platform, target...

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2.0

Jun 29, 2018
06/18

by
Srikanth Toppaladoddi; John S. Wettlaufer

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We study the seasonal changes in the thickness distribution of Arctic sea ice, $g(h)$, under climate forcing. Our analytical and numerical approach is based on a Fokker-Planck equation for $g(h)$ (Toppaladoddi \& Wettlaufer \emph{Phys. Rev. Lett.} {\bf 115}, 148501, 2015), in which the thermodynamic growth rates are determined using observed climatology. In particular, the Fokker-Planck equation is coupled to the observationally consistent thermodynamic model of Eisenman \& Wettlaufer...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1611.01045

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2.0

Jun 29, 2018
06/18

by
Michael P. Byrne; Paul A. O'Gorman

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Climate models simulate a strong land-ocean contrast in the response of near-surface relative humidity to global warming: relative humidity tends to increase slightly over oceans but decrease substantially over land. Surface energy balance arguments have been used to understand the response over ocean but are difficult to apply over more complex land surfaces. Here, a conceptual box model is introduced, involving moisture transport between the land and ocean boundary layers and...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1605.00380

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2.0

Jun 29, 2018
06/18

by
Anna S. von der Heydt; Peter Ashwin

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Equilibrium climate sensitivity (ECS) is a key predictor of climate change. However, it is not very well constrained, either by climate models or by observational data. The reasons for this include strong internal variability and forcing on many time scales. In practise this means that the 'equilibrium' will only be relative to fixing the slow feedback processes before comparing palaeoclimate sensitivity estimates with estimates from model simulations. In addition, information from the late...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1604.03311

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Jun 29, 2018
06/18

by
Arthur P. Guillaumin; Adam M. Sykulski; Sofia C. Olhede; Jeffrey J. Early; Jonathan M. Lilly

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We propose a new class of univariate nonstationary time series models, using the framework of modulated time series, which is appropriate for the analysis of rapidly-evolving time series as well as time series observations with missing data. We extend our techniques to a class of bivariate time series that are isotropic. Exact inference is often not computationally viable for time series analysis, and so we propose an estimation method based on the Whittle-likelihood, a commonly adopted...

Topics: Methodology, Fluid Dynamics, Atmospheric and Oceanic Physics, Applications, Physics, Statistics

Source: http://arxiv.org/abs/1605.09107

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2.0

Jun 29, 2018
06/18

by
Jinkai Li; Edriss S. Titi

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This paper is devoted to reviewing several recent developments concerning certain class of geophysical models, including the primitive equations (PEs) of atmospheric and oceanic dynamics and a tropical atmosphere model. The PEs for large-scale oceanic and atmospheric dynamics are derived from the Navier-Stokes equations coupled to the heat convection by adopting the Boussinesq and hydrostatic approximations, while the tropical atmosphere model considered here is a nonlinear interaction system...

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

Source: http://arxiv.org/abs/1604.01695

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Jun 29, 2018
06/18

by
Grigoris Katsiolides; Eike H. Müller; Robert Scheichl; Tony Shardlow; Michael B. Giles; David J. Thomson

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A common way to simulate the transport and spread of pollutants in the atmosphere is via stochastic Lagrangian dispersion models. Mathematically, these models describe turbulent transport processes with stochastic differential equations (SDEs). The computational bottleneck is the Monte Carlo algorithm, which simulates the motion of a large number of model particles in a turbulent velocity field; for each particle, a trajectory is calculated with a numerical timestepping method. Choosing an...

Topics: Physics, Numerical Analysis, Fluid Dynamics, Atmospheric and Oceanic Physics, Mathematics

Source: http://arxiv.org/abs/1612.07717

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Jun 29, 2018
06/18

by
Aseel Farhat; Evelyn Lunasin; Edriss S. Titi

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Analyzing the validity and success of a data assimilation algorithm when some state variable observations are not available is an important problem in meteorology and engineering. We present an improved data assimilation algorithm for recovering the exact full reference solution (i.e. the velocity and temperature) of the 3D Planetary Geostrophic model, at an exponential rate in time, by employing coarse spatial mesh observations of the temperature alone. This provides, in the case of this...

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

Source: http://arxiv.org/abs/1608.04770

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Jun 29, 2018
06/18

by
Elena Masciadri; Franck Lascaux; Alessio Turchi; Luca Fini

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One of the main goals of the feasibility study MOSE (MOdellig ESO Sites) is to evaluate the performances of a method conceived to forecast the optical turbulence above the ESO sites of the Very Large Telescope and the European-Extremely Large Telescope in Chile. The method implied the use of a dedicated code conceived for the optical turbulence (OT) called Astro-Meso-Nh. In this paper we present results we obtained at conclusion of this project concerning the performances of this method in...

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

Source: http://arxiv.org/abs/1612.00711

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Jun 29, 2018
06/18

by
Alexander M. R. Bakker; Tony E. Wong; Kelsey L. Ruckert; Klaus Keller

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Future sea-level rise poses nontrivial risks for many coastal communities. Managing these risks often relies on consensus projections like those provided by the IPCC. Yet, there is a growing awareness that the surrounding uncertainties may be much larger than typically perceived. Recently published sea-level projections appear widely divergent and highly sensitive to non-trivial model choices and the West Antarctic Ice Sheet (WAIS) may be much less stable than previously believed, enabling a...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1609.07119

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Jun 29, 2018
06/18

by
Kevin Günthner; Imran Khan; Dominique Elser; Birgit Stiller; Ömer Bayraktar; Christian R. Müller; Karen Saucke; Daniel Tröndle; Frank Heine; Stefan Seel; Peter Greulich; Herwig Zech; Björn Gütlich; Sabine Philipp-May; Christoph Marquardt; Gerd Leuchs

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The measurement of quantum signals that traveled through long distances is of fundamental and technological interest. We present quantum-limited coherent measurements of optical signals, sent from a satellite in geostationary Earth orbit to an optical ground station. We bound the excess noise that the quantum states could have acquired after having propagated 38600 km through Earth's gravitational potential as well as its turbulent atmosphere. Our results indicate that quantum communication is...

Topics: Quantum Physics, Atmospheric and Oceanic Physics, Emerging Technologies, Physics, Cryptography and...

Source: http://arxiv.org/abs/1608.03511

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1.0

Jun 29, 2018
06/18

by
Pascal Marquet

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The aim of this note is to derive the mixed-phase version of the moist-air entropy potential temperature $\theta_s$ derived in Marquet (2011). This mixed-phase version is suitable to describe parcels where liquid water and ice are allowed to coexist, with possible under- or super-saturations, with possible supercooled water and with possible different temperatures for dry air and water vapour, on the one hand, condensed water and ice, on the other hand. The impact of this new mixed-phase...

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

Source: http://arxiv.org/abs/1605.04382

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Jun 29, 2018
06/18

by
Bruno Issenmann; Claude Laroche; Eric Falcon

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We experimentally study gravity-capillary wave turbulence on the interface between two immiscible fluids of close density with free upper surface. We locally measure the wave height at the interface between both fluids by means of a highly sensitive laser Doppler vibrometer. We show that the inertial range of the capillary wave turbulence regime is significantly extended when the upper fluid depth is increased: The crossover frequency between the gravity and capillary wave turbulence regimes is...

Topics: Fluid Dynamics, Nonlinear Sciences, Atmospheric and Oceanic Physics, Physics, Classical Physics,...

Source: http://arxiv.org/abs/1610.05899

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Jun 29, 2018
06/18

by
Suhas DL; Jai Sukhatme; Joy M. Monteiro

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The response of the nonlinear shallow water equations (SWE) on a sphere to tropical vorticity forcing is examined with an emphasis on momentum fluxes and the emergence of a superrotating (SR) state. Fixing the radiative damping and momentum drag timescales to be of the order of a few days, a state of SR is shown to emerge under steady large-scale and random small-scale vorticity forcing. In the first example, the stationary response to a pair of equal and oppositely signed vortices placed on...

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1612.01719

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Jun 29, 2018
06/18

by
Joy M. Monteiro; Jai Sukhatme

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The derivation of a quasi-geostrophic (QG) system from the rotating shallow water equations on a midlatitude beta-plane coupled with moisture is presented. Condensation is prescribed to occur whenever the moisture at a point exceeds a prescribed saturation value. It is seen that a slow condensation time scale is required to obtain a consistent set of equations at leading order. Further, since the advecting wind fields are geostrophic, changes in moisture (and hence, precipitation) occur only...

Topics: Fluid Dynamics, Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1604.03656

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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 29, 2018
06/18

by
Kelsey L. Ruckert; Gary Shaffer; David Pollard; Yawen Guan; Tony E. Wong; Chris E. Forest; Klaus Keller

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The response of the Antarctic ice sheet (AIS) to changing climate forcings is an important driver of sea-level changes. Anthropogenic climate change may drive a sizeable AIS tipping point response with subsequent increases in coastal flooding risks. Many studies analyzing flood risks use simple models to project the future responses of AIS and its sea-level contributions. These analyses have provided important new insights, but they are often silent on the effects of potentially important...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1609.06338

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1.0

Jun 29, 2018
06/18

by
A. L. Virovlyansky

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A method is proposed for finding the wave field components which are weakly sensitive to the sound speed perturbation in the ocean acoustic waveguides. Such a component is formed by a narrow beam of rays whose spread in vertical direction, up to the observation range, remains less than the vertical scale of perturbation. These rays pass through practically the same inhomogeneities and therefore their phases acquire close increments. If the ray amplitudes vary insignificantly, then (i) the...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1610.02568

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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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Jun 29, 2018
06/18

by
J. B. Marston; G. P. Chini; S. M. Tobias

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Quasilinear theory is often utilized to approximate the dynamics of fluids exhibiting significant interactions between mean flows and eddies. In this paper we present a generalization of quasilinear theory to include dynamic mode interactions on the large scales. This generalized quasilinear (GQL) approximation is achieved by separating the state variables into large and small zonal scales via a spectral filter rather than by a decomposition into a formal mean and fluctuations. Nonlinear...

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

Source: http://arxiv.org/abs/1601.06720

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Jun 29, 2018
06/18

by
Chongsheng Cao; Jinkai Li; Edriss S. Titi

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In this paper, we consider the initial-boundary value problem of the three-dimensional primitive equations for oceanic and atmospheric dynamics with only horizontal viscosity and horizontal diffusivity. We establish the local, in time, well-posedness of strong solutions, for any initial data $(v_0, T_0)\in H^1$, by using the local, in space, type energy estimate. We also establish the global well-posedness of strong solutions for this system, with any initial data $(v_0, T_0)\in H^1\cap...

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

Source: http://arxiv.org/abs/1607.06252

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Jun 29, 2018
06/18

by
Mohammad Farazmand; Themistoklis P. Sapsis

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We consider the problem of large wave prediction in two-dimensional water waves. Such waves form due to the synergistic effect of dispersive mixing of smaller wave groups and the action of localized nonlinear wave interactions that leads to focusing. Instead of a direct simulation approach, we rely on the decomposition of the wave field into a discrete set of localized wave groups with optimal length scales and amplitudes. Due to the short-term character of the prediction, these wave groups do...

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

Source: http://arxiv.org/abs/1610.09558

Electro-magnetic (EM) propagation is greatly affected by atmospheric conditions. Although this subject has been an active area of research, a comprehensive evaporation ducting study for the Eastern Mediterranean Sea does not exist. The main objective of this thesis is to make detailed analyses of evaporation ducts in the Eastern Mediterranean Sea in support of Navy and civilian activities in the region. In this thesis, the European Center for Medium-Range Weather Forecasts (ECMWF) surface...

Topics: evaporation ducts, ducting, Mediterranean Sea, EM propagation, atmospheric effects on EM...

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Jun 29, 2018
06/18

by
Francisco J. Beron-Vera; Maria J. Olascoaga; Rick Lumpkin

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Recent surveys of marine plastic debris density have revealed high levels in the center of the subtropical gyres. Earlier studies have argued that the formation of great garbage patches is due to Ekman convergence in such regions. In this work we report a tendency so far overlooked of drogued and undrogued drifters to accumulate distinctly over the subtropical gyres, with undrogued drifters accumulating in the same areas where plastic debris accumulate. We show that the observed accumulation is...

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

Source: http://arxiv.org/abs/1606.02649

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Jun 29, 2018
06/18

by
Soumyabrata Dev; Shilpa Manandhar; Yee Hui Lee; Stefan Winkler

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Ground-based sky cameras (popularly known as Whole Sky Imagers) are increasingly used now-a-days for continuous monitoring of the atmosphere. These imagers have higher temporal and spatial resolutions compared to conventional satellite images. In this paper, we use ground-based sky cameras to detect the onset of rainfall. These images contain additional information about cloud coverage and movement and are therefore useful for accurate rainfall nowcast. We validate our results using rain gauge...

Topics: Physics, Computer Vision and Pattern Recognition, Computing Research Repository, Atmospheric and...

Source: http://arxiv.org/abs/1610.06667

Laser weapon systems, unlike conventional weapons, are heavily dependent upon the ever-changing atmospheric conditions in their employment theater. In order to understand the operational effectiveness of a laser weapon, the performance limits due to atmospheric conditions need to be understood. ANCHOR, a laser performance scaling code developed at the Naval Postgraduate School, is one such code used to model a laser's effectiveness for a variety of atmospheric conditions. This thesis focuses on...

Topics: thermal blooming, atmospheric propagation, laser, scaling code, Strehl ratio, ANCHOR, COAMPS,...

Understanding the vertical variations of temperature and humidity in the marine atmospheric surface layer (MASL) is extremely important for naval and civilian applications. In particular, such variations affect the propagation of electromagnetic waves (EM) by forming an evaporation duct. However, direct measurements of these profiles have been difficult from a large ship because of the disturbance introduced by the platform. In this thesis, the design, deployment, and initial data analyses of a...

Topics: evaporative duct, CASPER, maritime atmospheric surface layer, air-sea interaction, vertical profile

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Jun 29, 2018
06/18

by
Ankush Bhaskar; Durbha Sai Ramesh; Geeta Vichare; Triven Koganti; S. Gurubaran

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Identification and quantification of possible drivers of recent climate variability remain a challenging task. This important issue is addressed adopting a non-parametric information theory technique, the Transfer Entropy and its normalized variant. It distinctly quantifies actual information exchanged along with the directional flow of information between any two variables with no bearing on their common history or inputs, unlike correlation, mutual information etc. Measurements of greenhouse...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1607.01529

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Jun 29, 2018
06/18

by
Sylvain Robert; Hans R. Künsch

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The high dimensionality and computational constraints associated with filtering problems in large-scale geophysical applications are particularly challenging for the Particle Filter (PF). Approximate but efficient methods such as the Ensemble Kalman Filter (EnKF) are therefore usually preferred. A key element of these approximate methods is localization, which is in principle a general technique to avoid the curse of dimensionality and consists in limiting the influence of observations to...

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

Source: http://arxiv.org/abs/1610.03701

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Jun 29, 2018
06/18

by
X. San Liang

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The past years have seen the success of a novel multiscale energetic formalism in a variety of ocean and engineering fluid applications. In a self-contained way, this study introduces it to the atmospheric dynamical diagnostics, with important theoretical updates. Multiscale energy equations are derived using a new analysis apparatus, namely, multiscale window transform, with respect to both the primitive equation and quasi-geostrophic models. A reconstruction of the "atomic" energy...

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1606.05793

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Jun 29, 2018
06/18

by
Renzo Mosetti

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The observed pseudo-periodic reversal of the upper layer circulation of the Ionian Sea has been assumed to be related to some internal feedback processes (density driven) by the so called BiOS (Adriatic-Ionian Bimodal Oscillating System) hypothesis. The mechanism seems to be very well described by a non-linear oscillator dynamical system. By setting the state variables as the salinity of Adriatic deep water and the sea level anomaly in the Ionian region a Van der Pol equation has been obtained....

Topics: Atmospheric and Oceanic Physics, Physics

Source: http://arxiv.org/abs/1612.05254

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Jun 29, 2018
06/18

by
Kevin Heng; Shang-Min Tsai

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We present novel, analytical, equilibrium-chemistry formulae for the abundances of molecules in hot exoplanetary atmospheres that include the carbon, oxygen and nitrogen networks. Our hydrogen-dominated solutions involve acetylene (C$_2$H$_2$), ammonia (NH$_3$), carbon dioxide (CO$_2$), carbon monoxide (CO), ethylene (C$_2$H$_4$), hydrogen cyanide (HCN), methane (CH$_4$), molecular nitrogen (N$_2$) and water (H$_2$O). By considering only the gas phase, we prove that the mixing ratio of carbon...

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

Source: http://arxiv.org/abs/1603.05418

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Jun 29, 2018
06/18

by
Christophe Brouzet; Evgeny Ermanyuk; Sylvain Joubaud; Ilias Sibgatullin; Thierry Dauxois

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One of the pivotal questions in the dynamics of the oceans is related to the cascade of mechanical energy in the abyss and its contribution to mixing. Here, we propose internal wave attractors in the large amplitude regime as a unique self-consistent experimental and numerical setup that models a cascade of triadic interactions transferring energy from large-scale monochro-matic input to multi-scale internal wave motion. We also provide signatures of a discrete wave turbulence framework for...

Topics: Fluid Dynamics, Physics, Atmospheric and Oceanic Physics

Source: http://arxiv.org/abs/1602.06852

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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 29, 2018
06/18

by
Cihan Bayindir

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In this paper we study the properties of the chaotic wave fields generated in the frame of the Kundu-Eckhaus equation (KEE). Modulation instability results in a chaotic wave field which exhibits small-scale filaments with a free propagation constant, k. The average velocity of the filaments is approximately given by the average group velocity calculated from the dispersion relation for the plane-wave solution however direction of propagation is controlled by the $\beta$ parameter, the constant...

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

Source: http://arxiv.org/abs/1601.00209

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Jun 29, 2018
06/18

by
James Walsh

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M. Budyko and W. Sellers independently introduced seminal energy balance climate models in 1969, each with a goal of investigating the role played by positive ice albedo feedback in climate dynamics. In this paper we replace the relaxation to the mean horizontal heat transport mechanism used in the models of Budyko and Sellers with diffusive heat transport. We couple the resulting surface temperature equation with an equation for movement of the edge of the ice sheet (called the ice line),...

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

Source: http://arxiv.org/abs/1607.07769

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Jun 29, 2018
06/18

by
Denys Dutykh; Didier Clamond; Marx Chhay

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This manuscript is devoted to the modelling of water waves in the deep water regime with some emphasis on the underlying variational structures. The present article should be considered as a review of some existing models and modelling approaches even if new results are presented as well. Namely, we derive the deep water analogue of the celebrated Serre-Green-Naghdi equations which have become the standard model in shallow water environments. The relation to existing models is discussed....

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

Source: http://arxiv.org/abs/1607.00216

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Jun 29, 2018
06/18

by
Cecilia F. Mondaini; Edriss S. Titi

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We apply the Postprocessing Galerkin method to a recently introduced continuous data assimilation (downscaling) algorithm for obtaining a numerical approximation of the solution of the two-dimensional Navier-Stokes equations corresponding to given measurements from a coarse spatial mesh. Under suitable conditions on the relaxation (nudging) parameter, the resolution of the coarse spatial mesh and the resolution of the numerical scheme, we obtain uniform in time estimates for the error between...

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

Source: http://arxiv.org/abs/1612.06998

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Jun 29, 2018
06/18

by
J. F. Muzy; R. Baïle

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We introduce a variant of continuous random cascade models that extends former constructions introduced by Barral-Mandelbrot and Bacry-Muzy in the sense that they can be supported by sets of arbitrary fractal dimension. The so introduced sets are exactly self-similar stationary versions of random Cantor sets formerly introduced by Mandelbrot as "random cutouts". We discuss the main mathematical properties of our construction and compute its scaling properties. We then illustrate our...

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

Source: http://arxiv.org/abs/1601.03775