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Modelling Hierarchical FlockingApr 21 2019We present a general framework for modeling a wide selection of flocking scenarios under free boundary conditions. Several variants have been considered - including examples for the widely observed behavior of hierarchically interacting units. The models ... More

Detecting regime transitions in time series using dynamic mode decompositionApr 19 2019We employ the framework of the Koopman operator and dynamic mode decomposition to devise a method to detect transient dynamics and regime changes in time series. We argue that typically transient dynamics experiences the full phase space dimension with ... More

Why do some probabilistic forecasts lack reliability?Apr 18 2019In this work, we investigate the reliability of the probabilistic binary forecast. We mathematically prove that a necessary, but not sufficient, condition for achieving a reliable probabilistic forecast is maximizing the Peirce skill score (PSS) at the ... More

Improving solution accuracy and convergence for stochastic physics parameterizations with colored noiseApr 18 2019Stochastic parameterizations are used in numerical weather prediction and climate modeling to help improve the statistical distributions of the simulated phenomena. Earlier studies (Hodyss et al 2013, 2014) have shown that convergence issues can arise ... More

Spike-burst chimera states in an adaptive exponential integrate-and-fire neuronal networkApr 17 2019Chimera states are spatiotemporal patterns in which coherence and incoherence coexist. We observe the coexistence of synchronous (coherent) and desynchronous (incoherent) domains in a neuronal network. The network is composed of coupled adaptive exponential ... More

Power law error growth in multi-hierarchical chaotic systems -- a dynamical mechanism for finite prediction horizon in weather forecastsApr 17 2019We propose a dynamical mechanism for a scale dependent error growth rate, by the introduction of a class of hierarchical models. The coupling of time scales and length scales is motivated by atmospheric dynamics. This model class can be tuned to exhibit ... More

CloudSegNet: A Deep Network for Nychthemeron Cloud Image SegmentationApr 16 2019We analyze clouds in the earth's atmosphere using ground-based sky cameras. An accurate segmentation of clouds in the captured sky/cloud image is difficult, owing to the fuzzy boundaries of clouds. Several techniques have been proposed that use color ... More

Multiple-interaction kinetic modelling of a virtual-item gambling economyApr 16 2019In recent years, there has been a proliferation of online gambling sites, which made gambling more accessible with a consequent rise in related problems, such as addiction. Hence, the analysis of the gambling behaviour at both the individual and the aggregate ... More

The Fraction of Broken Waves in Natural Surf ZonesApr 15 2019This paper presents a novel quantification of the fraction of broken waves (Qb) in natural surf zones using data from seven wave-dominated Australian beaches. Qb is a critical, but rarely quantified, parameter for parametric surf zone energy dissipation ... More

Improved reliability and accuracy of CMIP5 global mean surface temperature projectionsApr 14 2019Climate predictions are only meaningful if the associated uncertainty is reliably estimated. A standard practice for providing climate projections is to use an ensemble of projections. The ensemble mean serves as the projection while the ensemble spread ... More

Martian cloud climatology and life cycle extracted from Mars Express OMEGA spectral imagesApr 12 2019A Martian water-ice cloud climatology has been extracted from OMEGA data covering 7 Martian years (MY 26-32). We derived two products, the Reversed Ice Cloud Index (ICIR) and the Percentage of Cloudy Pixels (PCP), indicating the mean cloud thickness and ... More

Effects of vorticity on the travelling waves of some shallow water two-component systemsApr 12 2019In the present study we consider three two-component (integrable and non-integrable) systems which describe the propagation of shallow water waves on a constant shear current. Namely, we consider the two-component Camassa-Holm equations, the Zakharov-Ito ... More

Extreme wave statistics in co-propagating windsea and swellApr 11 2019We investigate how the extreme wave statistics of a windsea is modified by a following swell, by means of laboratory experiments and simulations using a High Order Spectral Method (HOSM) of long-crested sea. The windsea spectrum is kept equal for all ... More

Analytic Reconstruction of a Two-Dimensional Velocity Field from an Observed Diffusive ScalarApr 09 2019Inverting an evolving diffusive scalar field to reconstruct the underlying velocity field is an underdetermined problem. Here we show, however, that for two-dimensional incompressible flows, this inverse problem can still be uniquely solved if high-resolution ... More

Analytic Reconstruction of a Two-Dimensional Velocity Field from an Observed Diffusive ScalarApr 09 2019Apr 11 2019Inverting an evolving diffusive scalar field to reconstruct the underlying velocity field is an underdetermined problem. Here we show, however, that for two-dimensional incompressible flows, this inverse problem can still be uniquely solved if high-resolution ... More

Constraining stochastic parametrisation schemes using high-resolution simulationsApr 09 2019Stochastic parametrisations are used in weather and climate models to improve the representation of unpredictable unresolved processes. When compared to a deterministic model, a stochastic model represents `model uncertainty', i.e., sources of error in ... More

The paradoxes of the Late Hesperian Mars oceanApr 08 2019The long-standing debate on the existence of ancient oceans on Mars has been recently revived by evidence for tsunami resurfacing events that date from the Late Hesperian geological era. It has been argued that these tsunami events originated from the ... More

Comparison of two early warning systems for regional flash flood hazard forecastingApr 07 2019The anticipation of flash flood events is crucial to issue warnings to mitigate their impact. This work presents a comparison of two early warning systems for real-time flash flood hazard forecasting at regional scale. The two systems are based in a gridded ... More

A Model of the Enhanced Vertical Mixing Induced by Wind-WavesApr 07 2019In the Navier-Stokes equations, a current is decomposed into four constituents: the mean flow, wave-orbital motion, wave-induced-turbulent and background-turbulent currents. Under certain statistical assumptions, this allows to separate the wave-induced ... More

Practical rare event sampling for extreme mesoscale weatherApr 06 2019Extreme mesoscale weather, including tropical cyclones, squall lines, and floods, can be enormously damaging and yet challenging to simulate; hence, there is a pressing need for more efficient simulation strategies. Here we present a new rare event sampling ... More

Spatially Extended Tests of a Neural Network Parametrization Trained by Coarse-grainingApr 06 2019General circulation models (GCMs) typically have a grid size of 25--200 km. Parametrizations are used to represent diabatic processes such as radiative transfer and cloud microphysics and account for sub-grid-scale motions and variability. Unlike traditional ... More

Long-term analysis of gauge-adjusted radar rainfall accumulations at European scaleApr 04 2019Monitoring continental precipitation over Europe with high resolution (2 km, 15 minutes) has been possible since the operational production of the OPERA composites from the European weather radar networks. The OPERA data are the essential input to a hazard ... More

Inferring the dynamics of oscillatory systems using recurrent neural networksApr 04 2019We investigate the predictive power of recurrent neural networks for oscillatory systems not only on the attractor, but in its vicinity as well. For this we consider systems perturbed by an external force. This allows us to not merely predict the time ... More

Graph clustering in industrial networksApr 03 2019The present work investigates clustering of a graph-based representation of industrial connections derived from international trade data by Hidalgo et al (2007) and confirms existence of around ten industrial clusters that are reasonably consistent with ... More

Novel transition and Bellerophon state in coupled Stuart-Landau oscillatorsApr 03 2019We study synchronization in a system of Stuart-Landau oscillators with frequency-weighted coupling. For three typical unimodal frequency distributions, namely, the Lorentzian, the triangle, and the uniform, we found that the first-order transition occurs ... More

A variable Prandtl number power spectrum of optical turbulence and its application to oceanic light propagationApr 03 2019Apr 12 2019Light interaction with the turbulent ocean can be fully characterized with the help of the power spectrum of the water's refractive index fluctuations, resulting from the combined effect of two scalars, temperature and salinity concentration advected ... More

A variable Prandtl number power spectrum of optical turbulence and its application to oceanic light propagationApr 03 2019Apr 09 2019Light interaction with the turbulent ocean can be fully characterized with the help of the power spectrum of the water's refractive index fluctuations, resulting from the combined effect of two scalars, temperature and salinity concentration advected ... More

A variable Prandtl number power spectrum of optical turbulence and its application to oceanic light propagationApr 03 2019Light interaction with the turbulent ocean can be fully characterized with the help of the power spectrum of the water's refractive index fluctuations, resulting from the combined effect of two scalars, temperature and salinity concentration advected ... More

Modulational stability of nonlinear saturated gravity wavesApr 01 2019Stationary gravity waves, such as mountain lee waves, are effectively described by Grimshaw's dissipative modulation equations even in high altitudes where they become nonlinear due to their large amplitudes. In this theoretical study, a wave-Reynolds ... More

Air-Sea Interactions on Titan: Lake Evaporation, Atmospheric Circulation, and Cloud FormationMar 30 2019Titan's abundant lakes and seas exchange methane vapor and energy with the atmosphere via a process generally known as air-sea interaction. This turbulent exchange process is investigated with an atmospheric mesoscale model coupled to a slab model representation ... More

Deep learning for ocean acoustic source localization using one sensorMar 29 2019A deep learning approach based on big data is proposed to locate broadband acoustic sources with one hydrophone in ocean waveguides. Several 50-layer residual neural networks, trained on a huge number of sound field replicas generated by an acoustic propagation ... More

An axisymmetric limit for the width of the Hadley cell on planets with large obliquity and long seasonalityMar 27 2019Hadley cells dominate the meridional circulation of terrestrial atmospheres. The Solar System terrestrial atmospheres, Venus, Earth, Mars and Titan, exhibit a large variety in the strength, width and seasonality of their Hadley circulation. Despite the ... More

The effects of crustal magnetic fields and solar EUV flux on ionopause formation at MarsMar 25 2019We study the ionopause of Mars using a database of 6,893 ionopause detections obtained over 11 years by the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) radar sounder. The ionopause, in this work, is defined as a steep density gradient ... More

A data-driven approach to precipitation parameterizations using convolutional encoder-decoder neural networksMar 25 2019Numerical Weather Prediction (NWP) models represent sub-grid processes using parameterizations, which are often complex and a major source of uncertainty in weather forecasting. In this work, we devise a simple machine learning (ML) methodology to learn ... More

Active topolectrical circuitsMar 25 2019We develop design principles for active topolectrical circuits (ATCs) by exploiting a mathematical correspondence between active mechanical metamaterials and nonlinear electronic circuits. Building on a generic nonlinear oscillator representation of active ... More

The exact geostrophic streamfunction for neutral surfacesMar 25 2019McDougall (1989) proved that neutral surfaces possess an exact geostrophic streamfunction, but its form has remained unknown. The exact geostrophic streamfunction for neutral surfaces is derived here. It involves a path integral of the specific volume ... More

Neutral surface topologyMar 25 2019Neutral surfaces, along which most of the mixing in the ocean occurs, are notoriously difficult objects: they do not exist as well-defined surfaces, and as such can only be approximated. In a hypothetical ocean where neutral surfaces are well-defined, ... More

A Generalized Linear Response Theory of Complex Networks with an Application to Renewable Fluctuations in MicrogridsMar 22 2019In this work we study the general linear response theory for the distribution of energy fluctuations through complex networks. We develop the response equations for oscillators coupled on arbitrary, directed and weighted networks, when subjected to stationary ... More

Fish aggregating devices drift like oceanographic drifters in the near-surface currents of the Atlantic and Indian OceansMar 22 2019Knowledge of ocean surface dynamics is crucial for oceanographic and climate research. The satellite-tracked movements of hundreds of drifters deployed by research and voluntary observing vessels provide high-frequency and high-resolution information ... More

Lifetimes of rogue wave events in direct numerical simulations of deep-water irregular sea wavesMar 21 2019The issue of rogue wave lifetimes is addressed in this study, which helps to detail the general picture of this dangerous oceanic phenomenon. The direct numerical simulations of irregular wave ensembles are performed to obtain the complete accurate data ... More

The CO2-broadened H2O continuum in the 100-1500 cm-1 region. Measurements, predictions and empirical modelMar 21 2019Transmission spectra of H$_2$O+CO$_2$ mixtures have been recorded, at 296, 325 and 366 K, for various pressures and mixture compositions using two experimental setups. Their analysis enables to retrieve values of the 'continuum' absorption by the CO$_2$-broadened ... More

Forecasting of the Thermosphere via Assimilation of Electron Density and Temperature DataMar 20 2019The paper presents experiments of driving a physics-based thermosphere model by assimilating electron density (Ne) and temperature (Tn) data using the ensemble adjustment Kalman filter (EAKF) technique. This study not only helps to gauge the accuracy ... More

Turing-like patterns in an asymmetric dynamic Ising modelMar 20 2019To investigate novel aspects of pattern formation in spin systems, we propose a mapping between reactive concentrations in a reaction-diffusion system and spin orientations in a dynamic multiple-spin Ising model. This specifically designed Ising model ... More

Global Stability Properties of the Climate: Melancholia States, Invariant Measures, and Phase TransitionsMar 20 2019For a wide range of values of the incoming solar radiation, the Earth features at least two attracting states, which correspond to competing climates. The warm climate is analogous to the present one; the snowball climate features global glaciation and ... More

NeuralHydrology - Interpreting LSTMs in HydrologyMar 19 2019Despite the huge success of Long Short-Term Memory networks, their applications in environmental sciences are scarce. We argue that one reason is the difficulty to interpret the internals of trained networks. In this study, we look at the application ... More

Emergent regularities and scaling in armed conflict dataMar 18 2019Mar 30 2019Large-scale armed conflict is a characteristic feature of modern societies. The statistics of conflict show remarkable regularities like power law distributions of fatalities and duration, but lack a unifying framework. We explore a large, detailed data ... More

Emergent regularities and scaling in armed conflict dataMar 18 2019Large-scale armed conflict is a characteristic feature of modern civilization. The statistics of conflict show remarkable regularities like power law distributions of fatalities and durations, but these properties have remained disparate, albeit prominent, ... More

Long wave interaction with a partially immersed body. Part I: Mathematical modelsMar 18 2019In the present article we consider the problem of wave interaction with a partially immersed, but floating body. We assume that the motion of the body is prescribed. The general mathematical formulation for this problem is presented in the framework of ... More

Predicting GPS-based PWV Measurements Using Exponential SmoothingMar 15 2019Global Positioning System (GPS) derived precipitable water vapor (PWV) is extensively being used in atmospheric remote sensing for applications like rainfall prediction. Many applications require PWV values with good resolution and without any missing ... More

Co-Contagion Diffusion on Multilayer NetworksMar 15 2019We study the interface of three elements of diffusion: the synergy between contagions, the dormancy rate of each individual contagion, and the multiplex network topology. Dormancy is defined as a weaker form of "immunity," where dormant nodes no longer ... More

Markov-chain-inspired search for MH370Mar 14 2019Markov-chain models are constructed for the probabilistic description of the drift of marine debris from Malaysian Airlines flight MH370. En route from Kuala Lumpur to Beijing, the MH370 mysteriously disappeared in the southeastern Indian Ocean on 8 March ... More

Multivariate statistical modelling of future marine stormsMar 13 2019Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design purposes. Such description should contain information on both the univariate behaviour and the joint-dependence of storm-variables. These two aspects have ... More

On the Perturbation of Self-Organized Urban Street NetworksMar 13 2019We investigate urban street networks as a whole within the frameworks of information physics and statistical physics. Urban street networks are envisaged as evolving social systems subject to a Boltzmann-mesoscopic entropy conservation. For self-organized ... More

Lightning and charge processes in brown dwarf and exoplanet atmospheresMar 11 2019Mar 13 2019The study of the composition of brown dwarf atmospheres helped to understand their formation and evolution. Similarly, the study of exoplanet atmospheres is expected to constrain their formation and evolutionary states. We use results from 3D simulations, ... More

Turing patterns mediated by network topology in homogeneous active systemsMar 09 2019Mechanisms of pattern formation---of which the Turing instability is an archetype---constitute an important class of dynamical processes occurring in biological, ecological and chemical systems. Recently, it has been shown that the Turing instability ... More

The transport and deposition of heavy particles in complex terrain: insights from an Eulerian model for large eddy simulationMar 08 2019The transport and deposition of heavy particles over complex surface topography by turbulent fluid flow is an important problem in a number of disciplines, including sediment and snow transport, ecology and plant pathology, aeolian processes, and geomorphology. ... More

Characterizing Evaporation Ducts Within the Marine Atmospheric Boundary Layer Using Artificial Neural NetworksMar 07 2019We apply a multilayer perceptron machine learning (ML) regression approach to infer electromagnetic (EM) duct heights within the marine atmospheric boundary layer (MABL) using sparsely sampled EM propagation data obtained within a bistatic context. This ... More

Morphology and dynamics of Venus's middle clouds with Akatsuki/IR1Mar 07 2019The Venusian atmosphere is covered by clouds with super-rotating winds whose accelerating mechanism is still not well understood. The fastest winds, occurring at the cloud tops ($\sim$70 km height), have been studied for decades thanks to their visual ... More

Collective movement in alarmed animals groups: a simple model with positional forces and a limited attention fieldMar 06 2019We perform a numerical analysis of a recent introduced model for describing collective movement in alarmed animals groups. This model, derived from a position-based interaction and a limited attention field, displays a non-equilibrium phase transition ... More

Classical many-body time crystalsMar 06 2019Discrete time crystals are a many-body state of matter where the extensive system's dynamics are slower than the forces acting on it. Nowadays, there is a growing debate regarding the specific properties required to demonstrate such a many-body state, ... More

Significant Impact of Rossby Waves on Air Pollution Detected by Network AnalysisMar 06 2019Air pollution is associated with human diseases and has been found to be related to premature mortality. In response, environmental policies have been adopted in many countries, to decrease anthropogenic air pollution for the improvement of long-term ... More

From cosmic explosions to terrestrial fires?Mar 04 2019Multiple lines of evidence point to one or more moderately nearby supernovae, with the strongest signal ~2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent ... More

Autumnal deep scattering layer from moored acoustic sensing in the subtropical Canary BasinMar 04 2019An enhanced acoustic scatterer reflectance layer was observed in the bathypelagic zone around 1650 m in the subtropical NE-Atlantic Ocean for about two months during autumn. It resembles a classic pattern of diapause-resting, possibly of large zooplankton, ... More

Analytical Estimation of the Width of Hadley Cells in the Solar SystemMar 01 2019The angular width of Earth's Hadley cell has been related to the square root of the product of the tropospheric thickness and the buoyancy frequency, and to the inverse of the square root of the angular velocity and the planetary radius. Here, this formulation ... More

Offshore Wind Turbines will encounter very low Atmospheric TurbulenceFeb 28 2019The rapid growth of offshore wind energy requires accurate modeling of the wind resource, which can be depleted by wind farm wakes. Turbulence dissipation rate governs the accuracy of model predictions of hub-height wind speed and the development and ... More

Improved Representation of Ocean Heat Content in Energy Balance ModelsFeb 27 2019Anomaly-diffusing energy balance models (AD-EBM) are routinely employed to analyze and emulate the warming response of both observed and simulated Earth systems. We demonstrate a deficiency in common multi-layer as well as continuous-diffusion AD-EBM ... More

Energy Constraints for Climate Models from Hydrologic PartitioningFeb 27 2019It is well known that evaporative cooling of Earth's surface water reduces the amount of radiation that goes into sensible heat, namely the portion of radiation that produces higher temperatures. However, a rigorous use of long-term hydrologic measurements ... More

Anomalous bulk-edge correspondence in continuous mediaFeb 26 2019Topology plays an increasing role in physics beyond the realm of topological insulators in condensed mater. From geophysical fluids to active matter, acoustics or photonics, a growing family of systems presents topologically protected chiral edge modes. ... More

Learning Dynamical Systems from Partial ObservationsFeb 26 2019We consider the problem of forecasting complex, nonlinear space-time processes when observations provide only partial information of on the system's state. We propose a natural data-driven framework, where the system's dynamics are modelled by an unknown ... More

Longwave radiative analysis of cloudy scattering atmospheres using a Net Exchange FormulationFeb 22 2019The Net Exchange Formulation (NEF) is an alternative to the usual radiative transfer equation. It was proposed in 1967 by Green [1] for atmospheric sciences and by Hottel [2] for engineering sciences. Until now, the NEF has been used only in a very few ... More

Heat and water vapor transfer in the wake of a falling ice sphere and its implication for secondary ice formation in cloudsFeb 21 2019We perform direct numerical simulations of the settling of an ice sphere in an ambient fluid accounting for heat and mass transfer with the aim of studying in a meteorological context the case of falling graupel in humid air. The study is motivated by ... More

Meridional Structure and Future Changes of Tropopause Height and TemperatureFeb 21 2019We use a simple, semi-analytic, column model to better understand the meridional structure of the tropopause height and the future changes in its height and temperature associated with global warming. The model allows us to separate the effects of tropospheric ... More

Optical turbulence forecast in the Adaptive Optics realmFeb 21 2019(35-words maximum) In this talk I present the scientific drivers related to the optical turbulence forecast applied to the ground-based astronomy supported by Adaptive Optics, the state of the art of the achieved results and the most relevant challenges ... More

Complex bifurcations in fast-slow climate dynamicsFeb 21 2019We consider a class of quadratic systems with slow and fast variables, which exhibit complicated bifurcations when the dynamic parameter (physically interpreted as the load on a system) is changing. We prove that this system with any two different structurally ... More

The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical modelsFeb 20 2019We use a hierarchy of numerical models (a 3-D Global Climate Model, a 1-D radiative-convective model and a 2-D Mantle Dynamics model) to explore the environmental effects of very large impacts on the atmosphere, surface and interior of early Mars. Using ... More

Unlikely existence of $k_x^{-1}$ spectral law in wall turbulence: an observation of the atmospheric surface layerFeb 20 2019For wall turbulence, there has been predicted a range of streamwise wavenumbers $k_x$ such that the spectral density of streamwise velocity fluctuations is proportional to $k_x^{-1}$. The existence or nonexistence of this $k_x^{-1}$ law is examined here. ... More

Cascading failures in scale-free interdependent networksFeb 19 2019Large cascades are a common occurrence in many natural and engineered complex systems. In this paper we explore the propagation of cascades across networks using realistic network topologies, such as heterogeneous degree distributions, as well as intra- ... More

Tropical and Extratropical General Circulation with a Meridional Reversed Temperature Gradient as Expected in a High Obliquity PlanetFeb 18 2019Planets with high obliquity receive more radiation in the polar regions than at low latitudes, and thus, assuming an ocean-covered surface with sufficiently high heat capacity, their meridional temperature gradient was shown to be reversed for the entire ... More

Open-ocean interior moored sensor turbulence estimates, below a MeddyFeb 18 2019A one-year time series of moored high-resolution temperature T-sensor data from 1455 m depth on a 3900 m long line in about 5300 m of water in the NE-Atlantic Canary Basin are dominated by salinity (over-)compensated intrusions arising from the effects ... More

Super-Resolution Simulation for Real-Time Prediction of Urban MicrometeorologyFeb 14 2019We propose a super-resolution (SR) simulation system that consists of a physics-based meteorological simulation and an SR method based on a deep convolutional neural network (CNN). The CNN is trained using pairs of high-resolution (HR) and low-resolution ... More

A Consistent Reduced Network for HCN Chemistry in Early Earth and Titan Atmospheres: Quantum Calculations of Reaction Rate CoefficientsFeb 14 2019HCN is a key ingredient for synthesizing biomolecules such as nucleobases and amino acids. We calculate 42 reaction rate coefficients directly involved with or in competition with the production of HCN in the early Earth or Titan atmospheres. These reactions ... More

Understanding the dynamics of biological and neural oscillator networks through mean-field reductions: a reviewFeb 14 2019Many biological and neural system can be seen as networks of interacting periodic processes. Importantly, the function of these networks depends on the collective dynamics: Synchrony of oscillations is probably amongst the most prominent examples of collective ... More

Understanding the dynamics of biological and neural oscillator networks through mean-field reductions: a reviewFeb 14 2019Feb 27 2019Many biological and neural systems can be seen as networks of interacting periodic processes. Importantly, the function of these networks depends on the collective dynamics: Synchrony of oscillations is probably amongst the most prominent examples of ... More

Wave attenuation and dispersion due to floating ice coversFeb 14 2019Experiments investigating the attenuation and dispersion of surface waves in a variety of ice covers are performed using a refrigerated wave flume. The ice conditions tested in the experiments cover naturally occurring combinations of continuous, fragmented, ... More

Observing Microscopic Transitions from Macroscopic Bursts: Instability-Mediated Resetting in the Incoherent Regime of the $D$-dimensional Generalized Kuramoto ModelFeb 13 2019We consider a recently introduced $D$-dimensional generalized Kuramoto model for many $(N\gg 1)$ interacting agents in which the agent states are $D$-dimensional unit vectors. It was previously shown that, for even $D$, similar to the original Kuramoto ... More

A method for generating coherent spatially explicit maps of seasonal palaeoclimates from site-based reconstructionsFeb 13 2019We describe a new method for reconstructing spatially explicit maps of seasonal palaeoclimate variables from site based reconstructions. Using a 3D-Variational technique, the method finds the best linear unbiased estimate of the palaeoclimate given the ... More

Numerical analysis of the multi-fluid equations with applications for convection modellingFeb 13 2019Convection schemes are a large source of error in global weather and climate models, and modern resolutions are often too fine to parameterize convection but are still too coarse to fully resolve it. Recently, numerical solutions of multi-fluid equations ... More

A theoretical model for realistic local climatesFeb 13 2019We address the question of writing a model that ---considering the doubly-periodic forcing induced by solar radiation and the laws of irradiance and conduction--- reproduces realistic annual and daily modulations of temperatures on the surface of a small ... More

A new diagnostic tool for water, energy and entropy budgets in climate modelsFeb 12 2019This work presents a novel diagnostic tool for studying the thermodynamics of the climate systems with a wide range of applications, from sensitivity studies to model tuning. It includes a number of modules for assessing the internal energy budget, the ... More

Deep Learning for Scientific Inference from Geophysical Data: The Madden-Julian Oscillation as a Test CaseFeb 12 2019Deep learning can recognize complex geophysical phenomena by inferring which variables are important for their identification and understanding their spatial characteristics. We use a particular mode of multi-scale tropical atmospheric variability, the ... More

The emission of energetic electrons from the complex streamer corona adjacent to leader steppingFeb 12 2019We here propose a model to capture the complexity of the streamer corona adjacent to leader stepping and relate it to the production of energetic electrons serving as a source of X-rays and $\gamma$-rays, manifesting in terrestrial gamma-ray flashes (TGFs). ... More

Surface waves enhance particle dispersionFeb 11 2019We study the horizontal dispersion of passive tracer particles on the free surface of gravity waves in deep water. For random linear waves with the JONSWAP spectrum, the Lagrangian particle trajectories are computed using an exact nonlinear model known ... More

Precipitable Water Vapor, Temperature, and Wind Statistics At Sites Suitable for mm and Submm Wavelength Astronomy in Northern ChileFeb 11 2019Atmospheric water vapor is the main limiting factor of atmospheric transparency in the mm and submm wavelength spectral windows. Thus, dry sites are needed for the installation and successful operation of radio astronomy observatories exploiting those ... More

Diffusion of inertia-gravity waves by geostrophic turbulenceFeb 11 2019The scattering of inertia-gravity waves by large-scale geostrophic turbulence in a rapidly rotating, strongly stratified fluid leads to the diffusion of wave energy on the constant-frequency cone in wavenumber space. We derive the corresponding diffusion ... More

Diffusion of inertia-gravity waves by geostrophic turbulenceFeb 11 2019Apr 09 2019The scattering of inertia-gravity waves by large-scale geostrophic turbulence in a rapidly rotating, strongly stratified fluid leads to the diffusion of wave energy on the constant-frequency cone in wavenumber space. We derive the corresponding diffusion ... More

Classifying attention deficit hyperactivity disorder in children with non-linearities in actigraphyFeb 10 2019Objective This study provides an objective measure based on actigraphy for Attention Deficit Hyperactivity Disorder (ADHD) diagnosis in children. We search for motor activity features that could allow further investigation into their association with ... More

Statistical Lyapunov theory based on bifurcation analysis of energy cascade in isotropic homogeneous turbulence: a physical--mathematical reviewFeb 09 2019This work presents a review of the previous articles dealing with an original turbulence theory proposed by the author, and provides new theoretical insights into some related issues. The new theoretical procedures and methodological approaches confirm ... More

The Influence of Time Series Distance Functions on Climate NetworksFeb 08 2019Network theory has established itself as an important tool for the analysis of complex systems such as the climate. In this context, climate networks are constructed using a spatiotemporal climate dataset and a time series distance function. It consists ... More

Derivation of Delay Equation Climate Models Using the Mori-Zwanzig FormalismFeb 08 2019Models incorporating delay have been frequently used to understand climate variability phenomena, but often the delay is introduced through an ad-hoc physical reasoning, such as the propagation time of waves. In this paper, the Mori-Zwanzig formalism ... More

Quantitative analysis of self-organized patterns in ombrotrophic peatlandsFeb 07 2019We numerically investigate a diffusion-reaction model of an ombrotrophic peatland implementing a Turing instability relying on nutrient accumulation. We propose a systematic and quantitative sorting of the vegetation patterns, based on the statistical ... More