total 4664took 0.15s

Modeling the impact of dilution on the microbial degradation time of dispersed oil in marine environmentsAug 21 2019Dispersants aid the breakup of crude oil masses and increase the available interfacial surface area for bacteria to degrade insoluble hydrocarbons in the marine environment. However, this common view neglects key aspects of the microscale interactions ... More

Two-frequency approach to the theory of atmospheric acoustic-gravity wavesAug 21 2019The propagation of acoustic-gravity waves (AGWs) in the stratified isothermal atmosphere is analyzed using methods of the oscillation theory. It is shown that AGW in the atmosphere can be considered as an oscillatory process occurring at two eigenfrequencies. ... More

Detection of Propadiene on TitanAug 20 2019The atmosphere of Titan, the largest moon of Saturn, is rich in organic molecules, and it has been suggested that the moon may serve as an analog for the pre-biotic Earth due to its highly reducing chemistry and existence of global hazes. Photochemical ... More

Nonlinear Rossby wave-wave and wave-mean flow theory for long term Solar cycle modulationsAug 19 2019The Schwabe cycle of solar activity exhibits modulations and frequency fluctuations on slow time scales of centuries and millennia. Plausible physical explanations for the cause of these long-term variations of the solar cycle are still elusive, with ... More

Digraphs are different: Why directionality matters in complex systemsAug 19 2019Many networks describing complex systems are directed: the interactions between elements are not symmetric. Recent work has shown that these networks can display properties such as trophic coherence or non-normality, which in turn affect stability, percolation ... More

The Traditional Approximation of Rotation including the centrifugal acceleration for slightly deformed starsAug 18 2019The Traditional Approximation of Rotation (TAR) is a treatment of the dynamical equations of rotating stably stratified fluids where the action of the Coriolis acceleration along the direction of the entropy (and chemicals) stratification is neglected ... More

Invariant parameterization of geostrophic eddies in the oceanAug 17 2019The framework of invariant parameterization is extended to higher-order closure schemes. We also define, for the first time, generalized invariant parameterization schemes, where symmetries of the corresponding original model are preserved as equivalence ... More

Indetermination of networks structure from the dynamics perspectiveAug 17 2019Networks are universally considered as complex structures of interactions of large multi-component systems. In order to determine the role that each node has inside a complex network, several centrality measures have been developed. Such topological features ... More

Dispersion in an array of buildings in stable and convective atmospheric conditionsAug 16 2019Wind tunnel experiments were conducted to study the impact of atmospheric stratification on flow and dispersion within and over a regular array of rectangular buildings. Three stable and two convective incoming boundary layers were tested with a Richardson ... More

Topological universality of on-demand ride-sharing efficiencyAug 16 2019Ride-sharing may substantially contribute to future-compliant sustainable mobility, both in urban and rural areas. The service quality of ride-sharing fleets jointly depends on the topology of the underlying street networks, the spatio-temporal demand ... More

Recurrent U-net: Deep learning to predict daily summertime ozone in the United StatesAug 16 2019We use a hybrid deep learning model to predict June-July-August (JJA) daily maximum 8-h average (MDA8) surface ozone concentrations in the US. A set of meteorological fields from the ERA-Interim reanalysis as well as monthly mean NO$_x$ emissions from ... More

Constraining the vertical distribution of coastal dust aerosol using OCO-2 O2 A-band measurementsAug 15 2019Quantifying the vertical distribution of atmospheric aerosols is crucial for estimating their impact on the Earth energy budget and climate, improving forecast of air pollution in cities, and reducing biases in the retrieval of greenhouse gases (GHGs) ... More

The nature of the diffuse light near cities detected in nighttime satellite imageryAug 15 2019Diffuse glow has been observed around brightly lit cities in nighttime satellite imagery since at least the first publication of large scale maps in the late 1990s. In the literature, this has often been assumed to be an error related to the sensor, and ... More

Stable and convective boundary-layer flows in an urban arrayAug 15 2019In this paper non-neutral approaching flows were employed in a meteorological wind tunnel on a regular urban-like array of rectangular buildings. As far as stable stratification is concerned, results on the flow above and inside the canopy show a clear ... More

Asymptotic solutions of stratified shear flow with horizontal eddy coefficient of turbulent viscosityAug 15 2019We consider linearized equations of perturbed mean flow under the Boussinesq approximation with the presence of eddy coefficients of turbulent viscosity but with the absence of turbulent diffusivity. By including both the horizontal and vertical eddy ... More

Superfast amplification and superfast nonlinear saturation of perturbations as the mechanism of turbulenceAug 13 2019Ruelle predicted that the maximal amplification of perturbations in homogeneous isotropic turbulence is exponential $e^{\sigma \sqrt{Re} t}$ (where $\sigma \sqrt{Re}$ is the maximal Liapunov exponent). In our earlier works, we predicted that the maximal ... More

Evaluation of soil thermal conductivity schemes for use in land surface modelingAug 13 2019Soil thermal conductivity is an important physical parameter in modeling land surface processes. Previous studies on evaluations of parameterization schemes of soil thermal conductivity are mostly based on specific experimental conditions or local soil ... More

The impact of using reconditioned correlated observation error covariance matrices in the Met Office 1D-Var systemAug 12 2019Recent developments in numerical weather prediction have led to the use of correlated observation error covariance (OEC) information in data assimilation and forecasting systems. However, diagnosed OEC matrices are often ill-conditioned and may cause ... More

Comparing Convective Self-Aggregation in Idealized Models to Observed Moist Static Energy Variability near the EquatorAug 10 2019Idealized convection-permitting simulations of radiative-convective equilibrium (RCE) have become a popular tool for understanding the physical processes leading to horizontal variability of tropical water vapor and rainfall. However, the applicability ... More

Characterizing the energetics of multi-scale asymmetries during tropical cyclone rapid intensity changesAug 09 2019Our collective understanding of azimuthally-asymmetric features within the coherent structure of a tropical cyclone (TC) continues to improve with the availability of more detailed observations and high-resolution model outputs. However, a precise understanding ... More

Progress during the NOPP Wave Model Improvement ProgramAug 09 2019This paper reviews the research activities that were carried out under the auspices of the National Ocean Partnership Program (NOPP) to advance research in wind wave modeling and transfer maturing technologies into operational community models. Primary ... More

Quantifying information loss on chaotic attractors through recurrence networksAug 08 2019We propose an entropy measure for the analysis of chaotic attractors through recurrence networks which are un-weighted and un-directed complex networks constructed from time series of dynamical systems using specific criteria. We show that the proposed ... More

A flood damage allowance framework for coastal protection with deep uncertainty in sea-level riseAug 07 2019Future projections of Antarctic ice sheet (AIS) mass loss remain characterized by deep uncertainty (i.e., behavior is not well understood or widely agreed upon by experts). This complicates decisions on long-lived projects involving the height of coastal ... More

Scaling Relations for Terrestrial Exoplanet Atmospheres from Baroclinic CriticalityAug 07 2019The macroturbulent atmospheric circulation of Earth-like planets mediates their equator-to-pole heat transport. For fast-rotating terrestrial planets, baroclinic instabilities in the mid-latitudes lead to turbulent eddies that act to transport heat poleward. ... More

Fractional dynamics on circulant multiplex networks: optimal coupling and long-range navigation for continuous-time random walksAug 07 2019This work analyzes fractional continuous-time random walks on two-layer multiplexes. A node-centric dynamics is used, in which it is assumed a Poisson distribution of a walker to become active, while a jump to one of its neighbors depends on the connection ... More

Simulation of the 2018 Global Dust Storm on Mars Using the NASA Ames Mars GCM: A Multi-Tracer ApproachAug 07 2019Global dust storms are the most thermodynamically significant dust events on Mars. They are produced from the combination of multiple local and regional lifting events and maintained by positive radiative-dynamic feedbacks. The most recent of these events, ... More

Oscillatory evolution of collective behavior in evolutionary games played with reinforcement learningAug 07 2019Large-scale cooperation underpins the evolution of ecosystems and the human society, and the collective behaviors by self-organization of multi-agent systems are the key for understanding. As artificial intelligence (AI) prevails in almost all branches ... More

Ethane in Titan's Stratosphere from Cassini CIRS Far- and Mid-Infrared SpectraAug 06 2019The Cassini Composite Infrared Spectrometer (CIRS) observed thermal emission in the far- and mid-infrared (from 10 cm$^{-1}$ to 1500 cm$^{-1}$), enabling spatiotemporal studies of ethane on Titan across the span of the Cassini mission from 2004 through ... More

Could short-lasting non-specific immunity explain seasonal spacing of epidemic diseases?Aug 02 2019Common respiratory viruses cause seasonal epidemics in sequential patterns. The underlying mechanisms for this pattern have been debated for some time. For influenza, contenders include temperature, humidity, and vitamin D levels. While such seasonal ... More

nsCouette -- A high-performance code for direct numerical simulations of turbulent Taylor-Couette flowAug 01 2019Aug 08 2019We present nsCouette, a highly scalable software tool to solve the Navier-Stokes equations for incompressible fluid flow between differentially heated and independently rotating, concentric cylinders. It is based on a pseudospectral spatial discretization ... More

nsCouette -- A high-performance code for direct numerical simulations of turbulent Taylor-Couette flowAug 01 2019We present nsCouette, a highly scalable software tool to solve the Navier-Stokes equations for incompressible fluid flow between differentially heated and independently rotating, concentric cylinders. It is based on a pseudospectral spatial discretization ... More

CloudSat-inferred vertical structure of precipitation over the Antarctic continentAug 01 2019Current global warming is causing significant changes in snowfall in polar regions, directly impacting the mass balance of the ice caps. The only water supply on Antarctica, precipitation, is poorly estimated from surface measurements over Antarctica. ... More

Modeling Daily Pan Evaporation in Humid Climates Using Gaussian Process RegressionAug 01 2019Evaporation is one of the main processes in the hydrological cycle, and it is one of the most critical factors in agricultural, hydrological, and meteorological studies. Due to the interactions of multiple climatic factors, the evaporation is a complex ... More

Carbon dioxide retrieval of Argus 1000 space data by using GENSPECT line-by-line radiative transfer modelJul 31 2019The micro-spectrometer Argus 1000 being in space continuously monitors the sources and sinks of the trace gases. It is commonly believed that among other gases $\text{CO}_\text{2}$ is the major contributor causing the greenhouse effect. Argus 1000 along ... More

Analog forecasting of extreme-causing weather patterns using deep learningJul 26 2019Numerical weather prediction (NWP) models require ever-growing computing time/resources, but still, have difficulties with predicting weather extremes. Here we introduce a data-driven framework that is based on analog forecasting (prediction using past ... More

Fitting In and Breaking Up: A Nonlinear Version of Coevolving Voter ModelsJul 26 2019We investigate a nonlinear version of coevolving voter models, in which both node states and network structure update as a coupled stochastic dynamical process. Most prior work on coevolving voter models has focused on linear update rules with fixed rewiring ... More

Internal wave mixing in warming Lake GrevelingenJul 26 2019Seasonal hypoxia or even anoxia can occur in some local deep basins of coastal waters. Such low summertime oxygen contents especially affect benthic life. The seasonal coastal hypoxia is commonly related to biological increased respiration and to physical ... More

Investigation on the Atmospheric Incoming Flow of a Utility-Scale Wind Turbine using Super-large-scale Particle Image VelocimetryJul 26 2019The atmospheric incoming flow of a wind turbine is intimately connected to its power production as well as its structural stability. Here we present an incoming flow measurement of a utility-scale turbine at the high spatio-temporal resolution, using ... More

Global Well-posedness for the Primitive Equations Coupled to Nonlinear Moisture Dynamics with Phase ChangesJul 25 2019In this work we study the global solvability of the primitive equations for the atmosphere coupled to moisture dynamics with phase changes for warm clouds, where water is present in the form of water vapor and in the liquid state as cloud water and rain ... More

Deep-ocean inertial subrange small bandwidth coherence and Ozmidov-frequency separationJul 25 2019The inertial subrange of turbulence in a density stratified environment is the transition from internal waves to isotropic turbulence, but it is unclear how to interpret its extension to anisotropic stratified turbulence. Knowledge about stratified turbulence ... More

Towards a Physically Motivated Planetary Accounting FrameworkJul 24 2019In this work we present a physically motivated planetary Accounting Framework for the Earth System. We show that the impact of the human activity in terms of the Planetary Boundary variables can be accounted for in our Landau-Ginzburg phase transition ... More

Uncertainty in the MAN Data Calibration & Trend EstimatesJul 23 2019We investigate trend identification in the LML and MAN atmospheric ammonia data. The signals are mixed in the LML data, with just as many positive, negative, and no trends found. The start date for trend identification is crucial, with the trends claimed ... More

Rossby Number Effects on Columnar Eddy Formation and the Energy Dissipation Law in Homogeneous Rotating TurbulenceJul 23 2019Two aspects of homogeneous rotating turbulence are quantified through forced Direct Numerical Simulations in an elongated domain, which is in the direction of rotation about $340$ times larger than the typical initial eddy size. First, by following the ... More

Ground/space, passive/active remote sensing observations coupled with particle dispersion modelling to understand the inter-continental transport of wildfire smoke plumesJul 23 2019During the 2017 record-breaking burning season in Canada / United States, intense wild fires raged during the first week of September in the Pacific northwestern region (British Columbia, Alberta, Washington, Oregon, Idaho, Montana and northern California) ... More

Explosive Phenomena in Complex NetworksJul 23 2019The emergence of large-scale connectivity and synchronization are crucial to the structure, function and failure of many complex socio-technical networks. Thus, there is great interest in analyzing phase transitions to large-scale connectivity and to ... More

VARENN: Graphical representation of spatiotemporal data and application to climate studiesJul 23 2019Analyzing and utilizing spatiotemporal big data are essential for studies concerning climate change. However, such data are not fully integrated into climate models owing to limitations in statistical frameworks. Herein, we employ VARENN (visually augmented ... More

Near-resonance tidal evolution of the Earth-Moon system influenced by orbital-scale climate changeJul 22 2019We build a coupled conceptual model of the climate and the tidal evolution of the Earth-Moon system to find the influence of the former on the latter. Energy balance model is applied to calculate steady temperature field from the mean annual insolation ... More

Learning spatiotemporal signals using a recurrent spiking network that discretizes timeJul 20 2019Learning to produce spatiotemporal sequences is a common task the brain has to solve. While many sequential behaviours differ superficially, the underlying organization of the computation might be similar. The way the brain learns these tasks remains ... More

Fast and robust computation of coherent Lagrangian vortices on very large two-dimensional domainsJul 19 2019Jul 30 2019We describe a new method for computing coherent Lagrangian vortices in two-dimensional flows according to any of the following approaches: black-hole vortices [Haller & Beron-Vera, 2013], objective Eulerian Coherent Structures (OECSs) [Serra & Haller, ... More

Fast and robust computation of coherent Lagrangian vortices on very large two-dimensional domainsJul 19 2019We describe a new method for computing coherent Lagrangian vortices in two-dimensional flows according to any of the following approaches: black-hole vortices [Haller & Beron-Vera, 2013], objective Eulerian Coherent Structures (OECSs) [Serra & Haller, ... More

Martian Year 34 Column Dust Climatology from Mars Climate Sounder Observations: Reconstructed Maps and Model SimulationsJul 18 2019We have reconstructed longitude-latitude maps of column dust optical depth (CDOD) for Martian year (MY) 34 (May 5, 2017 --- March 23, 2019) using observations by the Mars Climate Sounder (MCS) aboard NASA's Mars Reconnaissance Orbiter spacecraft. Our ... More

Remote sensing of angular scattering effect of aerosols in a North American megacityJul 18 2019The angle-dependent scattering effect of aerosols in the atmosphere can be used to infer their compositions, which in turn is important to understand their impacts of human health and Earth climate. The aerosol phase function, which characterizes the ... More

Atmospheric Electricity at the Ice GiantsJul 16 2019Lightning was detected by Voyager 2 at Uranus and Neptune, and weaker electrical processes also occur throughout planetary atmospheres from galactic cosmic ray (GCR) ionisation. Lightning is an indicator of convection, whereas electrical processes away ... More

Shallow water equations on a fast rotating surfaceJul 16 2019Jul 19 2019We prove that for rotating shallow water equations on a surface of revolution with variable Coriolis parameter and vanishing Rossby and Froude numbers, the classical solution satisfies uniform estimates on a fixed time interval with no dependence on the ... More

Shallow water equations on a fast rotating surfaceJul 16 2019We prove that for rotating shallow water equations on a surface of revolution with variable Coriolis parameter and vanishing Rossby and Froude numbers, the classical solution satisfies uniform estimates on a fixed time interval with no dependence on the ... More

Slowing-down reduction and Possible Reversal Trend of Tropospheric NO2 over China during 2016 to 2019Jul 15 2019Atmospheric nitrogen dioxide (NO2) over China at national level has been kept reducing since 2011 as seen from both satellite observations, ground-based measurements and bottom-up emission inventory (Liu et al., 2016; Irie et al., 2016; Krotkov et al., ... More

A dynamic over games drives selfish agents to win-win outcomesJul 15 2019Understanding the evolution of human social systems requires flexible formalisms for the emergence of institutions. Although game theory is normally used to model interactions individually, larger spaces of games can be helpful for modeling how interactions ... More

Downward Terrestrial Gamma-ray Flash observed in Winter ThunderstormJul 14 2019During a winter thunderstorm on 2017 November 24, a strong burst of gamma rays with energies up to $\sim$10~MeV was detected coincident with a lightning discharge, by scintillation detectors installed at Kashiwazaki-Kariwa Nuclear Power Station at sea ... More

Soil and soil CO2 magnify greenhouse effectJul 13 2019Soil has been recognized as an indirect driver of global warming by regulating atmospheric greenhouse gases. However, in view of the higher heat capacity and CO2 concentration in soil than those in atmosphere, the direct contributions of soil to greenhouse ... More

Rotational and rotational-vibrational Raman spectroscopy of air to characterize astronomical spectrographsJul 12 2019Raman scattering enables unforeseen uses for the laser guide-star system of the Very Large Telescope. Here, we present the observation of one up-link sodium laser beam acquired with the ESPRESSO spectrograph at a resolution $\lambda/\Delta\lambda \sim ... More

Computation of extremes values of time averaged observables in climate models with large deviation techniquesJul 12 2019One of the goals of climate science is to characterize the statistics of extreme and potentially dangerous events in the present and future climate. Extreme events like heat waves, droughts, or floods due to persisting rains are characterized by large ... More

NanoCarb part 2: Performance assessment for total column CO2 monitoring from a nano-satelliteJul 12 2019NanoCarb is an innovative Fourier Transform imaging spectrometer dedicated to the measurement of CO2 and CH4. Both its unusual optical principle and sampling strategy allows to reach a compact design, ideal for small satellite constellation as investigated ... More

Estimating tropospheric and stratospheric winds using infrasound from explosionsJul 12 2019The receiver-to-source backazimuth of atmospheric infrasound signals is biased when cross-winds are present along the propagation path. Infrasound from 598 surface explosions from over 30 years in northern Finland is measured with high spatial resolution ... More

Residual cross-grid flow numerical error in large-eddy simulations of cumulus-topped boundary layersJul 12 2019A computational domain translation velocity is often used in LES simulations to improve computational performance by allowing longer time-step intervals. Even though the equations of motion are Galilean invariant, LES results have been observed to depend ... More

Mobility restores the mechanism which supports cooperation in the voluntary prisoner's dilemma gameJul 11 2019It is generally believed that in a situation where individual and collective interests are in conflict, the availability of optional participation is a key mechanism to maintain cooperation. Surprisingly, this effect is sensitive to the use of microscopic ... More

Fixation properties of rock-paper-scissors games in fluctuating populationsJul 11 2019Jul 12 2019Rock-paper-scissors games metaphorically model cyclic dominance in ecology and microbiology. In a static environment, these models are characterized by fixation probabilities obeying two different "laws" in large and small well-mixed populations. Here, ... More

Fixation properties of rock-paper-scissors games in fluctuating populationsJul 11 2019Rock-paper-scissors games metaphorically model cyclic dominance in ecology and microbiology. In a static environment, these models are characterized by fixation probabilities obeying two different "laws" in large and small well-mixed populations. Here, ... More

A Data-Driven Approach for Accurate Rainfall PredictionJul 10 2019In recent years, there has been growing interest in using Precipitable Water Vapor (PWV) derived from Global Positioning System (GPS) signal delays to predict rainfall. However, the occurrence of rainfall is dependent on a myriad of atmospheric parameters. ... More

Discontinuous Galerkin discretization for two-equation turbulence closure modelJul 10 2019Accurate representation of vertical turbulence is crucial for numerical ocean modelling, both in global and coastal applications. The state-of-the-art approach is to use two-equation turbulence closure models which introduces two dynamic equations to ... More

Efficient Dynamical Downscaling of General Circulation Models Using Continuous Data AssimilationJul 09 2019Continuous data assimilation (CDA) is successfully implemented for the first time for efficient dynamical downscaling of a global atmospheric reanalysis. A comparison of the performance of CDA with the standard grid and spectral nudging techniques for ... More

Self-Localized Solitons of the Nonlinear Wave Blocking ProblemJul 08 2019Jul 15 2019In this paper, we propose a numerical framework to study the shapes, dynamics and the stabilities of the self-localized solutions of the nonlinear wave blocking problem. With this motivation, we use the nonlinear Schr\"odinger equation (NLSE) derived ... More

Self-Localized Solitons of the Nonlinear Wave Blocking ProblemJul 08 2019In this paper, we propose a numerical framework to study the shapes, dynamics and the stabilities of the self-localized solutions of the nonlinear wave blocking problem. With this motivation, we use the nonlinear Schr\"odinger equation (NLSE) derived ... More

Single-spectrum prediction of kurtosis of water waves in a non-conservative modelJul 08 2019We study statistical properties after a sudden episode of wind for water waves propagating in one direction. A wave with random initial conditions is propagated using a forced-damped higher order Nonlinear Schr\"odinger equation (NLS). During the wind ... More

Co-existing climate attractors in a coupled aquaplanetJul 07 2019The first step in exploring the properties of dynamical systems like the Earth climate is to identify the different phase space regions where the trajectories asymptotically evolve, called `attractors'. In a given system, multiple attractors can co-exist ... More

Co-existing climate attractors in a coupled aquaplanetJul 07 2019Aug 09 2019The first step in exploring the properties of dynamical systems like the Earth climate is to identify the different phase space regions where the trajectories asymptotically evolve, called `attractors'. In a given system, multiple attractors can co-exist ... More

Mapping PM2.5 concentration at sub-km level resolution: a dual-scale retrieval methodJul 06 2019Satellite-based retrieval has become a popular PM2.5 monitoring method currently. To improve the retrieval performance, multiple variables are usually introduced as auxiliary variable in addition to aerosol optical depth (AOD). Different kinds of variables ... More

Estimation of spatio-temporal wave grouping properties using Delaunay triangulation and spline techniquesJul 05 2019Jul 08 2019Wave groups can be detected and studied by using the wave envelope. So far, the method used to compute the wave envelope employs the Riesz transform. However, such a technique always produces symmetric envelopes, which is only realistic in the case of ... More

Estimation of spatio-temporal wave grouping properties using Delaunay triangulation and spline techniquesJul 05 2019Wave groups can be detected and studied by using the wave envelope. So far, the method used to compute the wave envelope employs the Riesz transform. However, such a technique always produces symmetric envelopes, which is only realistic in the case of ... More

Effective networks: a model to predict network structure and critical transitions from datasetsJul 04 2019Real-world complex systems such as ecological communities and neuron networks are essential parts of our everyday lives. These systems are composed of units which interact through intricate networks. The ability to predict sudden changes in network behaviour, ... More

Dominance, Sharing, and Assessment in an Iterated Hawk--Dove GameJul 03 2019Animals use a wide variety of strategies to reduce or avoid aggression in conflicts over resources. These strategies range from sharing resources without outward signs of conflict to the development of dominance hierarchies, in which initial fighting ... More

Wave-ice interaction in the North-West Barents SeaJul 03 2019The results of field work on drift ice during wave propagation are analyzed and presented. The field work was performed in the Barents Sea, and the main focus of the paper is on wave processes in the MIZ. A model of wave damping in broken ice is formulated ... More

Do wind-generated waves under steady forcing propagate primarily in the downwind direction?Jul 02 2019Measuring the directional distribution of ocean waves is a difficult task in ocean wave research. For many decades, wind-generated waves are assumed to propagate primarily in the wind direction. The concept is applied either implicitly or explicitly in ... More

Cohesive self-organization of mobile microrobotic swarmsJul 02 2019Mobile microrobots are envisioned to be useful in a wide range of high-impact applications, many of which requiring cohesive group formation to maintain self-bounded swarms in the absence of confining boundaries. Cohesive group formation relies on a balance ... More

Online learning as a way to tackle instabilities and biases in neural network parameterizationsJul 02 2019Over the last couple of years, machine learning parameterizations have emerged as a potential way to improve the representation of sub-grid processes in atmospheric models. All previous studies created a training dataset from a high-resolution simulation, ... More

Online learning as a way to tackle instabilities and biases in neural network parameterizationsJul 02 2019Jul 26 2019Over the last couple of years, machine learning parameterizations have emerged as a potential way to improve the representation of sub-grid processes in atmospheric models. All studies so far created a training dataset from a high-resolution simulation, ... More

Experimental Evidence of Hydrodynamic Instantons: The Universal Route to Rogue WavesJul 02 2019A statistical theory of rogue waves is proposed and tested against experimental data collected in a long water tank where random waves with different degrees of nonlinearity are mechanically generated and free to propagate along the flume. Strong evidence ... More

Evidence against a general positive eddy feedback in atmospheric blockingJul 01 2019The eddy straining mechanism of Shutts (1983; S83) has long been considered a main process for explaining the maintenance of atmospheric blocking. As hypothesized in S83, incoming synoptic eddies experience a meridional straining effect when approaching ... More

No experimental evidence for the significant anthropogenic climate changeJun 29 2019In this paper we will prove that GCM-models used in IPCC report AR5 fail to calculate the influences of the low cloud cover changes on the global temperature. That is why those models give a very small natural temperature change leaving a very large change ... More

Orientation dynamics of sedimenting anisotropic particles in turbulenceJun 29 2019We examine the dynamics of small anisotropic particles (spheroids) sedimenting through homogeneous isotropic turbulence using direct numerical simulations and theory. The gravity-induced inertial torque acting on sub-Kolmogorov spheroids leads to pronouncedly ... More

SuperDARN Observations of Semidiurnal Tidal Variability in the MLT and the Response to Sudden Stratospheric Warming EventsJun 28 2019Using meteor wind data from the Super Dual Auroral Radar Network (SuperDARN) in the Northern Hemisphere, we (1) demonstrate that the migrating (Sun-synchronous) tides can be separated from the nonmigrating components in the mesosphere and lower thermosphere ... More

Is Life (or at least socio-economic aspects of it) just Spin and Games?Jun 27 2019The enterprise of trying to explain different social and economic phenomena using concepts and ideas drawn from physics has a long history. Statistical mechanics, in particular, has been often seen as most likely to provide the means to achieve this, ... More

Reduced-Order Quasilinear Model of Ocean Boundary-Layer TurbulenceJun 27 2019The combined effectiveness of model reduction and the quasilinear approximation for the reproduction of the low-order statistics of oceanic surface boundary-layer turbulence is investigated. Idealized horizontally homogeneous problems of surface-forced ... More

Taking drift-diffusion analysis from the study of turbulent flows to the study of particulate matter smog and air pollutants dynamicsJun 27 2019Drift-diffusion analysis has been introduced in physics as a method to study turbulent flows. In the current study, it is proposed to use the method to identify underlying dynamical models of particulate matter smog, ozone and nitrogen dioxide concentrations. ... More

Well-posedness of strong solutions to the anelastic equations of stratified viscous flowsJun 26 2019We establish the local and global well-posedness of strong solutions to the two- and three-dimensional anelastic equations of stratified viscous flows. In this model, the interaction of the density profile with the velocity field is taken into account, ... More

Drift of pancake ice floes in the winter Antarctic marginal ice zone during polar cyclonesJun 26 2019High temporal resolution in--situ measurements of pancake ice drift are presented, from a pair of buoys deployed on floes in the Antarctic marginal ice zone during the winter sea ice expansion, over nine days in which the region was impacted by four polar ... More

Spiral wave propagation in communities with spatially correlated heterogeneityJun 24 2019Many multicellular communities propagate signals in a directed manner via excitable waves. Cell-to-cell heterogeneity is a ubiquitous feature of multicellular communities, but the effects of heterogeneity on wave propagation are still unclear. Here we ... More

Extended-range statistical ENSO prediction through operator-theoretic techniques for nonlinear dynamicsJun 22 2019Forecasting the El Nino-Southern Oscillation (ENSO) has been a subject of vigorous research due to the important role of the phenomenon in climate dynamics and its worldwide socioeconomic impacts. Over the past decades, numerous models for ENSO prediction ... More

Models of Continuous-Time Networks with Tie Decay, Diffusion, and ConvectionJun 22 2019The study of temporal networks in discrete time has yielded numerous insights into time-dependent networked systems in a wide variety of applications. For many complex systems, however, it is useful to develop continuous-time models of networks and to ... More

Eddy saturation of the Southern Ocean: a baroclinic versus barotropic perspectiveJun 20 2019"Eddy saturation" is the regime in which the total time-mean volume transport of an oceanic current is insensitive to the wind stress forcing and is often invoked as a dynamical description of Southern Ocean circulation. We revisit the problem of eddy ... More

Simulating the influence of sea-surface-temperature (SST) on tropical cyclones over South-West Indian ocean, using the UEMS-WRF regional climate modelJun 19 2019Tropical cyclones remain a major threat to the lives, property and economy of communities around the South West Indian ocean (SWIO), notably Southern Africa and Madagascar. This study uses the weather research forecast (WRF) model to perform a series ... More