Filtering by Subject: Physics

Data-driven prediction of a multi-scale Lorenz 96 chaotic system using deep learning methods: Reservoir computing, ANN, and RNN-LSTM

Ashesh Chattopadhyay, Pedram Hassanzadeh, Devika Subramanian

Published: 2019-06-20
Subjects: Applied Mathematics, Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamic Systems, Earth Sciences, Fluid Dynamics, Non-linear Dynamics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics

In this paper, the performance of three deep learning methods for predicting short-term evolution and for reproducing the long-term statistics of a multi-scale spatio-temporal Lorenz 96 system is examined. The methods are: echo state network (a type of reservoir computing, RC-ESN), deep feed-forward artificial neural network (ANN), and recurrent neural network with long short-term memory [...]

Distributed sensing of earthquakes and ocean-solid Earth interactions on seafloor telecom cables

Anthony Sladen, Diane Rivet, Jean Paul Ampuero, et al.

Published: 2019-06-07
Subjects: Earth Sciences, Environmental Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Physics

Two thirds of the surface of our planet are covered by water and are still poorly instrumented, which has prevented the earth science community from addressing numerous key scientific questions. The potential to leverage the existing fiber optic seafloor telecom cables that criss-cross the oceans, by turning them into dense arrays of seismo-acoustic sensors, remains to be evaluated. Here, we [...]

Representation of European hydroclimatic patterns with Self-Organizing Maps

Yannis Markonis, Filip Strnad

Published: 2019-05-14
Subjects: Climate, Earth Sciences, Environmental Sciences, Hydrology, Life Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics, Planetary Sciences

Self-Organizing Maps provide a powerful, non-linear technique of dimensionality reduction that can be used to identify clusters with similar attributes. Here, they were constructed from a 1000-year-long gridded palaeoclimatic dataset, namely the Old World Drought Atlas, to detect regions of homogeneous hydroclimatic variability across the European continent. A classification scheme of 10 regions [...]

Characterising strong force networks produced during granular shear using percolation methods: Revealing the bridge between local grain scale processes and macroscopic sliding

Karen Mair, Espen Jettestuen, Steffen Abe

Published: 2019-04-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure

Faults, landslides and subglacial till often contain accumulations of granular debris. Their macroscopic motion is at least to some extent determined by the processes operating in this sheared granular material. A valid question in these environments is how the local behaviour at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and [...]

A simplified seasonal forecasting strategy, applied to wind and solar power in Europe

Philip Bett, Hazel E. Thornton, Alberto Troccoli, et al.

Published: 2019-04-01
Subjects: Applied Statistics, Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics, Physics, Probability, Statistics and Probability, Sustainability

We demonstrate levels of skill for forecasts of seasonal-mean wind speed and solar irradiance in Europe, using seasonal forecast systems available from the Copernicus Climate Change Service (C3S). While skill is patchy, there is potential for the development of climate services for the energy sector. Following previous studies, we show that, where there is skill, a simple linear regression-based [...]

Minimal surfaces in porous media: pore-scale imaging of multiphase flow in an altered-wettability Bentheimer sandstone

Qingyang Lin, Branko Bijeljic, Steffen Berg, et al.

Published: 2019-03-28
Subjects: Earth Sciences, Fluid Dynamics, Physical Sciences and Mathematics, Physics

We observed features of pore scale fluid distributions during oil-brine displacement in a mixed-wet sandstone rock sample. High-resolution X-ray imaging was used in combination with differential pressure measurements to measure relative permeability and capillary pressure simultaneously during a steady-state waterflood experiment on a sample of Bentheimer sandstone 51.6 mm long and 6.1 mm in [...]

The Impact of Melting Ice Sheets on Future Global Climate

Dimitri Defrance, Thibault Catry, Amélie Rajaud, et al.

Published: 2019-03-22
Subjects: Climate, Earth Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Physics

That is a preprint of an article suubmitted at Applied Greography (20tf of March 19). Climate change studies in the last decades have been based on Global Climate Models (GCM), and the distribution of climatic regions over time extracted from these models can be represented using the Köppen climatic classification. The Köppen approach predicts the distribution of biomes worldwide on the basis of [...]

Poroelastic effects destabilize mildly rate-strengthening friction to generate stable slow slip pulses

Elias Rafn Heimisson, Eric M Dunham, Martin Almquist

Published: 2019-03-18
Subjects: Applied Mechanics, Earth Sciences, Engineering, Geology, Geophysics and Seismology, Mechanical Engineering, Physical Sciences and Mathematics, Physics, Statistical, Nonlinear, and Soft Matter Physics, Tribology

Slow slip events on tectonic faults, sliding instabilities that never accelerate to inertially limited ruptures or earthquakes, are one of the most enigmatic phenomena in frictional sliding. While observations of slow slip events continue to mount, a plausible mechanism that permits instability while simultaneously limiting slip speed remains elusive. Rate-and-state friction has been successful [...]

Hydrodynamic control of gas-exchange velocity in small streams

Andreas Lorke, Pascal Bodmer, Kaan Koca, et al.

Published: 2019-03-02
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Fluid Dynamics, Hydraulic Engineering, Physical Sciences and Mathematics, Physics, Planetary Sciences

Gas exchange is a critical component of any biogeochemical mass balance model of dissolved gases in aquatic systems, yet the magnitude and drivers of spatial and temporal variations of air-water exchange rates in shallow streams are poorly understood. We investigated the relationships between gas exchange velocity of carbon dioxide and methane and flow hydraulics at different sections along a [...]

High-resolution prediction of organic matter concentration with hyperspectral imaging on a sediment core

Kévin Jacq, Yves Perrette, Fanget Bernard, et al.

Published: 2019-02-21
Subjects: Analytical Chemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Optics, Physical Sciences and Mathematics, Physics, Sedimentology, Statistical Models, Statistics and Probability

In the case of environmental samples, the use of a chemometrics-based prediction model is highly challenging because of the difficulty in experimentally creating a well-ranged reference sample set. In this study, we present a methodology using short wave infrared hyperspectral imaging to create a partial least squares regression model on a cored sediment sample. It was applied to a sediment core [...]

Calibration of astigmatic particle tracking velocimetry based on generalized Gaussian feature extraction

Simon Franchini, Alexandros Charogiannis, Christos N. Markides, et al.

Published: 2018-11-20
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Engineering, Fluid Dynamics, Hydrology, Life Sciences, Physical Sciences and Mathematics, Physics

Flow and transport in porous media are driven by pore scale processes. Particle tracking in transparent porous media allows for the observation of these processes at the time scale of ms. We demonstrate an application of defocusing particle tracking using brightfield illumination and a CMOS camera sensor. The resulting images have relatively high noise levels. To address this challenge, we [...]

Lubrication of dislocation glide in forsterite by Mg vacancies: insights from Peierls-Nabarro modeling

Richard Skelton, Andrew Walker

Published: 2018-07-26
Subjects: Condensed Matter Physics, Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Physics

Dislocation glide is an important contributor to the rheology of olivine under conditions of high stress and low to moderate temperature, such as occur in mantle wedges. Interactions between point defects and dislocation core may alter the Peierls stress,

Higher potential compound flood risk in Northern Europe under anthropogenic climate change

Emanuele Bevacqua, Douglas Maraun, Michalis I. Vousdoukas, et al.

Published: 2018-07-18
Subjects: Applied Mathematics, Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Multivariate Analysis, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Physics, Statistics and Probability

The published version of this article is available at Compound flooding (CF) is an extreme event taking place in low-lying coastal areas as a result of co-occurring high sea level and large amounts of runoff, caused by precipitation. The impact from the two hazards occurring individually can be significantly lower than the result of their [...]

Tracking CO2 plumes in clay-rich rock by distributed fiber optic strain sensing (DFOSS): a laboratory demonstration

Yi Zhang, Ziqiu Xue, Hyuck Park, et al.

Published: 2018-04-25
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Mineral Physics, Oil, Gas, and Energy, Optics, Physical Sciences and Mathematics, Physics

Monitoring the migration of pore pressure, deformation, and saturation plumes with effective tools is important for the storage and utilization of fluids in underground reservoirs, such as geological stores of carbon dioxide (CO2) and natural gas. Such tools would also verify the security of the fluid contained reservoir–caprock system. Utilizing the swelling strain attributed to pressure [...]

River deltas as Multiplex networks: A framework for studying multi-process multi-scale connectivity via coupled-network theory

Alejandro Tejedor, Anthony Longjas, Paola Passalacqua, et al.

Published: 2018-04-13
Subjects: Applied Mathematics, Dynamic Systems, Earth Sciences, Environmental Sciences, Geomorphology, Hydrology, Mathematics, Non-linear Dynamics, Physical Sciences and Mathematics, Physics, Statistical, Nonlinear, and Soft Matter Physics

Transport of water, nutrients or energy fluxes in many natural or coupled human-natural systems occurs along different pathways that often have a wide range of transport timescales and might exchange fluxes with each other dynamically (e.g., surface-subsurface). Understanding this type of transport is key to predicting how landscapes will change under changing forcing. Here, we present a general [...]


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