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Publisher: Elsevier   (Total: 3168 journals)

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Showing 1 - 200 of 3168 Journals sorted alphabetically
Academic Pediatrics     Hybrid Journal   (Followers: 39, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 26, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 105, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 28, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 42, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 7)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6)
Acta Astronautica     Hybrid Journal   (Followers: 454, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 30, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 3)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 11, SJR: 0.18, CiteScore: 1)
Acta Histochemica     Hybrid Journal   (Followers: 5, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 330, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 12, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2, SJR: 1.793, CiteScore: 6)
Acta Poética     Open Access   (Followers: 4, SJR: 0.101, CiteScore: 0)
Acta Psychologica     Hybrid Journal   (Followers: 26, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access   (Followers: 1)
Acta Tropica     Hybrid Journal   (Followers: 7, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 7, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 8)
Acute Pain     Full-text available via subscription   (Followers: 15, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 18, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 9, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 13, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 23)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 200, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 12, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 17, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 30, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 12, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 12, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 24, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 15, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 1, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 35, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 5)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 14)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 29, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 11, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 11, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 26, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 16)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 13)
Advances in Digestive Medicine     Open Access   (Followers: 12)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 7)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Ecological Research     Full-text available via subscription   (Followers: 44, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 29, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 8)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 52, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 67, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Genetics     Full-text available via subscription   (Followers: 21, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 7, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 3, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 37, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 9, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 21, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 15, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 9, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 5, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 25)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 5)
Advances in Oncobiology     Full-text available via subscription   (Followers: 2)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 27, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 19)
Advances in Pharmacology     Full-text available via subscription   (Followers: 17, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 11)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 68)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (Followers: 3, SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 6)
Advances in Space Research     Full-text available via subscription   (Followers: 437, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 13, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 37, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 20)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 15)
Advances in Virus Research     Full-text available via subscription   (Followers: 6, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 55, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 396, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 12, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 493, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (Followers: 1, SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 18, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 32, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 45, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 4)
Agriculture and Natural Resources     Open Access   (Followers: 3)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 58, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 8, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 12, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 12)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 2, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 11, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 11, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 54, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 6, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 58, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 67, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 47, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 13)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 37, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 29, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 37, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 50)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 279, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 66, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 32, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 28, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 39, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 7)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 67, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 25, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription   (Followers: 1)
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 5, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 44, SJR: 1.512, CiteScore: 5)
Analytica Chimica Acta : X     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 221, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 13, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 14)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 25, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)
Animal Behaviour     Hybrid Journal   (Followers: 237, SJR: 1.58, CiteScore: 3)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 7, SJR: 0.937, CiteScore: 2)
Animal Reproduction Science     Hybrid Journal   (Followers: 7, SJR: 0.704, CiteScore: 2)

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Similar Journals
Journal Cover
Advances in Water Resources
Journal Prestige (SJR): 1.551
Citation Impact (citeScore): 3
Number of Followers: 55  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0309-1708
Published by Elsevier Homepage  [3168 journals]
  • A new collision operator for lattice Boltzmann shallow water model: a
           convergence and stability study
    • Abstract: Publication date: Available online 30 November 2019Source: Advances in Water ResourcesAuthor(s): Sara Venturi, Silvia Di Francesco, Martin Geier, Piergiorgio ManciolaAbstractThis work presents a new lattice Boltzmann model for steady and unsteady two-dimensional shallow water flows. Compared to previous lattice Boltzmann based shallow water models, the proposed method uses a consistent characteristic speed in the pressure term and in the viscosity. To preserve the isotropy of viscosity, the relaxation rates for the different cumulants have to be decoupled. This is only possible by using multiple relaxation rates. The recovery of the correct viscosity is investigated by a convergence study based on the decay of a Taylor Green Vortex. Results from shallow water models using the proposed collision operator are then compared to those derived from standard BGK approach and from a continuous model.
       
  • Experiments on grain size segregation in bedload transport on a steep
           slope
    • Abstract: Publication date: Available online 30 November 2019Source: Advances in Water ResourcesAuthor(s): P. Frey, H. Lafaye de Micheaux, C. Bel, R. Maurin, K. Rorsman, T. Martin, C. DucottetAbstractSediment transport in mountain and gravel-bed-rivers is characterized by bedload transport of a wide range of grain sizes. When the bed is moving, dynamic void openings permit downward infiltration of the smaller particles. This process, termed here ‘kinetic sieving’, has been studied in industrial contexts, but more rarely in fluvial sediment transport. We present an experimental study of two-size mixtures of coarse spherical glass beads entrained by turbulent and supercritical steady water flows down a steep channel with a mobile bed. The particle diameters were 4mm and 6mm, and the channel inclination 10%. The spatial and temporal evolution of the segregating smaller 4mm diameter particles was studied through the introduction of the smaller particles at a low constant rate into the large particle bedload flow at transport equilibrium. Particle flows were filmed from the side by a high-speed camera. Using original particle tracking algorithms, the position and velocity of both small and large particles were determined. Results include the time evolution of the layer of segregating smaller beads, assessment of segregation velocity and particle depth profiles. Segregation resulted in the progressive establishment of a quasi-continuous region of small particles reaching a steady-state penetration depth. The segregation dynamics showed a logarithmic time decreasing trend. This evolution was demonstrated to be dependent on the particle streamwise shear rate which decays downwards exponentially. This result is comparable to theories initially developed for dry granular flows.
       
  • Bed shear stress and sediment entrainment potential for breaking of
           internal solitary waves
    • Abstract: Publication date: Available online 29 November 2019Source: Advances in Water ResourcesAuthor(s): Giovanni la Forgia, Talia Tokyay, Claudia Adduce, George ConstantinescuAbstractWe investigate the interaction of strongly non linear internal solitary waves (ISWs) with boundaries having different slopes by means of high-resolution 3D large Eddy Simulations (LES). Releasing a volume of fresh water into a stratified ambient fluid, three different breaking mechanisms are produced: plunging, collapsing and surging breakers. The different shoaling dynamics affect the ISW evolution over the sloping boundary, inducing different effects on the bottom. In order to investigate the effects of the ISW breaking on the inclined surface, we calculate the bed shear stress and estimate the local flux of sediments entrained from the bed. We analyze the relationship between the breaking criteria and the related effects on the sloping surface. Although plunging breakers are expected to induce significant effects within the fluid, causing larger amount of mixing and fluid entrainment, the effects on the bottom are totally opposite. The collapsing breaker mechanism, indeed, generates boundary layer separation, which in turn induces whirling instabilities. Results show that the ISW interaction with the inclined surface occurs in its close proximity for collapsing breaker mechanism, which explains why the largest bed shear stresses and sediment re-suspension are predicted in the simulation where a collapsing breaker mechanism is observed.
       
  • Information theory-based multi-objective design of rainfall network for
           streamflow simulation
    • Abstract: Publication date: Available online 29 November 2019Source: Advances in Water ResourcesAuthor(s): Wenqi Wang, Dong Wang, Vijay P. Singh, Yuankun Wang, Jichun Wu, Jianyun Zhang, Jiufu Liu, Ying Zou, Ruimin HeAbstractRainfall data are needed for water resource management and decision making and are obtained from rainfall networks. These data are especially important for streamflow simulations and forecasting the occurrence of intense rainfall during the flood season. Therefore, rainfall networks should be carefully designed and evaluated. Several methods are used for rainfall network design, and information theory-based methods have recently received significant attention. This study focuses on the design of a rainfall network, especially for streamflow simulation. A multi-objective design method is proposed and applied to the Wei River basin in China. We use the total correlation as an indicator of information redundancy and multivariate transinformation as an indicator of information transfer. Information redundancy refers to the overlap of information between rainfall stations, and information transfer refers to the rainfall-runoff relationship. The outlet streamflow station (Huaxian station in the Wei River basin) is used as the target station for the streamflow simulation. A non-dominated sorting genetic algorithm (NSGA‐II) was used for the multi-objective optimization of the rainfall network design. We compared the proposed multi-objective design with two other methods using an artificial neural network (ANN) model. The optimized rainfall network from the proposed method led to reasonable outlet streamflow forecasts with a balance between network efficiency and streamflow simulation. Our results indicate that the multi-objective strategy provides an effective design by which the rainfall network can consider the rainfall-runoff process and benefit streamflow prediction on a catchment scale.
       
  • Quantification of predictive uncertainty in hydrological modelling by
           harnessing the wisdom of the crowd: A large-sample experiment at monthly
           timescale
    • Abstract: Publication date: Available online 27 November 2019Source: Advances in Water ResourcesAuthor(s): Georgia Papacharalampous, Hristos Tyralis, Demetris Koutsoyiannis, Alberto MontanariAbstractPredictive hydrological uncertainty can be quantified by using ensemble methods. If properly formulated, these methods can offer improved predictive performance by combining multiple predictions. In this work, we use 50-year-long monthly time series observed in 270 catchments in the United States to explore the performances provided by an ensemble learning post-processing methodology for issuing probabilistic hydrological predictions. This methodology allows the utilization of flexible quantile regression models for exploiting information about the hydrological model's error. Its key differences with respect to basic two-stage hydrological post-processing methodologies using the same type of regression models are that (a) instead of a single point hydrological prediction it generates a large number of “sister predictions” (yet using a single hydrological model), and that (b) it relies on the concept of combining probabilistic predictions via simple quantile averaging. A major hydrological modelling challenge is obtaining probabilistic predictions that are simultaneously reliable and associated to prediction bands that are as narrow as possible; therefore, we assess both these desired properties of the predictions by computing their coverage probabilities, average widths and average interval scores. The results confirm the usefulness of the proposed methodology and its larger robustness with respect to basic two-stage post-processing methodologies. Finally, this methodology is empirically proven to harness the “wisdom of the crowd” in terms of average interval score, i.e., the average of the individual predictions combined by this methodology scores no worse –usually better− than the average of the scores of the individual predictions.
       
  • Quantification of predictive uncertainty in hydrological modelling by
           harnessing the wisdom of the crowd: Methodology development and
           investigation using toy models
    • Abstract: Publication date: Available online 23 November 2019Source: Advances in Water ResourcesAuthor(s): Georgia Papacharalampous, Demetris Koutsoyiannis, Alberto MontanariAbstractWe introduce an ensemble learning post-processing methodology for probabilistic hydrological modelling. This methodology generates numerous point predictions by applying a single hydrological model, yet with different parameter values drawn from the respective simulated posterior distribution. We call these predictions “sister predictions”. Each sister prediction extending in the period of interest is converted into a probabilistic prediction using information about the hydrological model's errors. This information is obtained from a preceding period for which observations are available, and is exploited using a flexible quantile regression model. All probabilistic predictions are finally combined via simple quantile averaging to produce the output probabilistic prediction. The idea is inspired by the ensemble learning methods originating from the machine learning literature. The proposed methodology offers larger robustness in performance than basic post-processing methodologies using a single hydrological point prediction. It is also empirically proven to “harness the wisdom of the crowd” in terms of average interval score, i.e., the obtained quantile predictions score no worse –usually better− than the average score of the combined individual predictions. This proof is provided within toy examples, which can be used for gaining insight on how the methodology works and under which conditions it can optimally convert point hydrological predictions to probabilistic ones. A large-scale hydrological application is made in a companion paper.
       
  • Identifying relevant hydrological and catchment properties in active
           subspaces: An inference study of a lumped karst aquifer model
    • Abstract: Publication date: Available online 23 November 2019Source: Advances in Water ResourcesAuthor(s): Daniel Bittner, Mario Teixeira Parente, Steven Mattis, Barbara Wohlmuth, Gabriele ChiognaAbstractThe use of the active subspace method was recently proposed to reduce the dimension of complex hydrological models, perform sensitivity analysis of model parameters and quantify the uncertainty affecting model parameters. Although this inversion method is highly promising in terms of computational performance, a clear hydrological interpretation of the meaning of the active subspace that it identifies is missing. In this work, we infer how the active subspace changes in dimension and feature depending on geometrical and hydrological properties of the karst aquifer model LuKARS. We find that both the hydrotope area coverage and model parameters describing the catchment characteristics (here: water storage and discharge properties of the hydrotopes) have major impacts on the active subspace. Our results show that the active subspace method can be used to investigate the relation between the model structure, the area of a hydrotope and the simulated spring discharge.
       
  • Sensitivity and model reduction of simulated snow processes: contrasting
           observational and parameter uncertainty to improve prediction
    • Abstract: Publication date: Available online 23 November 2019Source: Advances in Water ResourcesAuthor(s): Anna Ryken, Lindsay A. Bearup, Jennifer L. Jefferson, Paul Constantine, Reed M. MaxwellAbstractThe hydrology of high-elevation, mountainous regions is poorly represented in Earth Systems Models (ESMs), yet these ecosystems play an important role in the storage and land-atmosphere exchange of water. As much of the western United States’ water comes from water stored in the snowpack (snow water equivalent, SWE), model representation of these regions is important. This study assesses how uncertainty in both model parameters and forcing affect simulated snow processes through sensitivity analysis (active subspaces) on model inputs (meteorological forcing and model input parameters) for a widely used snow model. Observations from an AmeriFlux tower at the Niwot Ridge research site are used to force an integrated, single-column hydrologic model, ParFlow-CLM. This study finds that trees can mute the effects of snow albedo causing the evergreen needleleaf scenarios to be sensitive primarily to hydrologic forcing while bare ground simulations are more sensitive to the snow parameters. The bare ground scenarios are most sensitive overall. Both forcing and model input parameters are important for obtaining accurate hydrologic model results.
       
  • Two-phase flow of CO2-brine in a heterogeneous sandstone: Characterization
           of the rock and comparison of the lattice-Boltzmann, pore-network, and
           direct numerical simulation methods
    • Abstract: Publication date: Available online 18 November 2019Source: Advances in Water ResourcesAuthor(s): Amir H. Kohanpur, Mahsa Rahromostaqim, Albert J. Valocchi, Muhammad SahimiAbstractUnderstanding the physics of two-phase flow of CO2 and brine in porous geological formations is essential to sequestration of carbon dioxide in deep saline reservoirs, as well as the older problem of enhanced oil recovery from hydrocarbon reservoirs by CO2 injection. A pilot CO2 injection in Decatur, Illinois, was undertaken, with the injection zone being the highly saline and heterogeneous Mt. Simon sandstone, in order to better understand the feasibility of full-scale sequestration process. This paper reports the results of an extensive study of the morphology of the sandstone and its heterogeneity, and simulation of single-phase and two-phase flow of CO2 and brine in the formation's three-dimensional images. As we demonstrate by extensive analysis, the formation is much more heterogeneous than the typical sandstone, such as Berea sandstone. In addition to characterizing the morphology of the sandstone and computing its important flow characteristics, an important goal of the study is to compare the accuracy and computational efficiency of three distinct simulation approaches, namely, the lattice-Boltzmann (LB) approach, direct numerical simulation (DNS) of the governing equations of fluid flow that uses the finite-volume method coupled with the OpenFOAM simulator, and pore-network (PN) simulation. After validating the simulators by comparing the computed relative permeabilities that they produce for Berea sandstone, we simulate displacement of brine by CO2 at low and relatively high capillary numbers, and compute the relative permeabilities and other quantities of interest. We demonstrate that all the three methods provide consistent relative permeability-saturation functions that are in close agreement with one another. However, although the LB and DNS both produce similar relative permeabilities, the DNS approach is computationally more efficient because it simulates drainage by only a single set of computations over the entire saturation range, whereas the LB simulation requires separate simulation for each set saturation. Thus, the question of what method to use for simulating such flow processes at the scale of core plugs should mainly be addressed based on the computational time that one can afford and the computational resources that one has access to. Another important question addressed is the effect of the resolution of the computational grids or lattices used, particularly when one uses the LB method with voxelized images of porous media. We show that, unlike many claims in the past, one may need many lattice units per voxel in order to obtain reliable, lattice-independent results.
       
  • Effects of Variable-Density Flow on the Value-of-Information of Pressure
           and Concentration Data for Aquifer Characterization
    • Abstract: Publication date: Available online 18 November 2019Source: Advances in Water ResourcesAuthor(s): Seonkyoo Yoon, Seunghak Lee, John R. Williams, Peter K. KangAbstractPredicting variable-density flow and transport in aquifers is critical for the management of many coastal saline aquifers. Accurate characterization of hydrogeological parameters is critical for prediction, and the characterization is often conducted by assimilating data into models. However, few studies have investigated the underlying physics controlling the value-of-information (VOI) of data for aquifer characterization. In this study, we show how a greater understanding of the underlying physics controlling pressure and concentration data coupling can lead to improved characterization. In variable-density flow, the key physics that controls the VOI of pressure and concentration data is the non-linear coupling between flow and transport via fluid density which causes the pressure field to experience transient changes according to the evolution of salinity distribution. We first demonstrate the coupling between pressure and concentration data using information theory, and then systematically investigate how the variable-density flow impacts the VOI of these data in relation to permeability estimation. Using an ensemble Kalman filter, we estimate the permeability field of saline aquifer systems in two scenarios of data usage: pressure data only, and pressure and concentration data jointly. This study demonstrates that, regardless of the data usage scenario, the maximum VOI of data is obtained when free convection and forced convection are balanced. We further show that the advantage of joint inversion of pressure and concentration data decreases as the coupling effect between flow and transport increases. Finally, we study how the level of permeability field heterogeneity affects the coupling, which in turn controls VOI of pressure and concentration data.
       
  • Anomalous Transport through Free-Flow-Porous Media Interface: Pore-Scale
           Simulation and Predictive Modeling
    • Abstract: Publication date: Available online 18 November 2019Source: Advances in Water ResourcesAuthor(s): Jun Song Kim, Peter K. KangAbstractPore-scale velocity and turbulence structures near streambeds may control solute transport and dispersion in streams. In this study, pore-scale flow and transport simulations are performed to investigate the effects of pore-scale processes on anomalous transport, which is often manifested by remarkably long residence times of solute particles, in coupled free-flow and porous media systems. By solving the 2D Reynolds-averaged Navier-Stokes equations integrated with a renormalization group k − ε turbulence model, we resolve complex pore-scale flows featured by vortices and preferential flows. Then, we incorporate the simulated velocity and turbulence fields into a Lagrangian particle tracking model that considers advection, turbulent diffusion, and molecular diffusion. Simulation results reveal that the interplay between pore-scale vortices and turbulence structures near the free-flow-permeable bed interface controls anomalous transport. High porosity induces strong turbulence penetration and preferential flow paths within permeable beds. The enhanced subsurface turbulence facilitates the escape of solute particles from recirculation zones via turbulent diffusion, causing steep power-law slopes in breakthrough curves (BTCs). In contrast, low porosity introduces heavy tailing in BTCs from particles that are trapped in the near-interface recirculation zones characterized by low velocities and limited turbulence. We upscale and predict particle transport via a Spatial Markov model (SMM) honoring the interplay between Lagrangian velocity distribution and velocity correlation. The SMM reproduces anomalous transport behaviors obtained from the numerical simulations. These results demonstrate that Lagrangian velocity statistics effectively encode anomalous transport mechanisms in the coupled systems.
       
  • Numerical Modelling of consolidation-induced solute transport in
           unsaturated soil with dynamic hydraulic conductivity and degree of
           saturation
    • Abstract: Publication date: Available online 14 November 2019Source: Advances in Water ResourcesAuthor(s): S Wu, D-S Jeng, BR SeymourAbstractThe effects of the pore pressure related dynamic hydraulic conductivity and dynamic degree of saturation on the consolidation-induced solute transport in deformable unsaturated soils are investigated. The storage equation and solute transport equations are revised to account for the dependence of these two soil parameters on pore pressures. Three dynamic models were conducted for dynamic hydraulic conductivity, dynamic degree of saturation, and both. Compared with the conventional model, the simulation results showed that both hydraulic conductivity and degree of saturation increased near the soil surface where pore pressure exceeded air-entry value. Dynamic hydraulic conductivity results in a slightly slower solute transport while dynamic degree of saturation accelerates the migration of contaminants. Including both dynamic effects produced limited differences in solute concentration, while consolidation results were affected significantly. Although dynamic degree of saturation has some influences on consolidation-induced solute transport, the correlation of the dynamic path is less significant. The air-entry value is an important parameter to determine when soil parameters become dynamic, and it affects the soil consolidation process in certain extent. This study provides new methods to incorporate in-homogeneous soil parameters, which are not only spatiotemporal variables, but also dynamic variations with pore pressure.
       
  • On modeling subgrid-scale macro-structures in narrow twisted channels
    • Abstract: Publication date: Available online 13 November 2019Source: Advances in Water ResourcesAuthor(s): Zhi Li, Ben R. HodgesAbstractPorosity-based subgrid topography models often fail to capture the effects of subgrid-scale topographic features in the interior of coarse grid cells. Existing approaches that modify bottom roughness or a drag coefficient are inadequate for macro-structures (large emergent or submerged obstacles) in subgrid-scale narrow twisted channels. Such structures partially block the cross-sectional area and provide enhanced topographic dissipation – effects that are not well represented by a drag coefficient that scales on a coarse-grid cell-averaged velocity and the cell volume. The relative alignment between mesh and flow further complicates this problem as it makes the subgrid model sensitive to mesh design. In the present study, three new approaches for simulating subgrid-scale macro-structures in narrow channels are proposed. The interior partial-blocking effect of structures is modeled as reduction of grid face-area. The sheltering of flow volumes around obstacles, which leads to topographic dissipation, is modeled by reducing the cell volume in the momentum equation (only). A mesh-shift procedure is designed to optimize mesh alignment for identifiable subgrid features. Combining the three subgrid methods improves the approximation of surface elevation and in-channel flow rate with a coarse-grid model. Tests are conducted for channelized flow using both synthetic domains and real marsh topography. The new methods reduce the overall mesh dependency of the subgrid model and provides stronger physical connection between effects of macro-structures and their geometry at coarse grid scales.
       
  • CO2-brine relative permeability and capillary pressure of Tuscaloosa
           sandstone: Effect of anisotropy
    • Abstract: Publication date: Available online 12 November 2019Source: Advances in Water ResourcesAuthor(s): Sahar Bakhshian, Seyyed A. Hosseini, Larry W. LakeAbstractRelative permeability and capillary pressure are known as essential properties that have substantial impacts on the accuracy of reservoir simulations. The effect of small-scale heterogeneity and lamination in the rock structure is often ignored during the measurement of capillary pressure and relative permeability curves in core samples. This study highlights the remarkable impact of anisotropy on the multiphase flow properties of stratified formations. A series of steady-state CO2-brine drainage and imbibition tests are conducted at reservoir conditions in horizontal and vertical core samples of the Tuscaloosa sandstone from the Cranfield CO2 injection site in Mississippi. The relative permeability curves represent an anisotropic behavior influenced by the heterogeneous and laminated structure of realistic rock samples. The CO2 saturation profiles during drainage and imbibition cycles indicate that the phase distribution in the pore space is controlled by core-scale heterogeneity in the porosity distribution among the laminations that causes capillary pressure inhomogeneity. Using the saturation profile during the imbibition cycle, the trapping characteristic of the horizontal and vertical rock samples are compared and we found that the capillary trapping is less likely in the vertical direction. Furthermore, the centrifuge-measured capillary pressure demonstrates distinctive characteristics for horizontal and vertical core samples. Since the flooding experiments are performed under capillary controlled flow, the capillary pressure contrast in the laminated structure of the rock strongly affects the relative permeability. The presented results can potentially improve the accuracy of the large-scale simulations for the CO2 post-injection period, in which the vertical displacement has an important role in the plume migration.
       
  • Future floods using hydroclimatic simulations and peaks over threshold: An
           alternative to nonstationary analysis inferred from trend tests
    • Abstract: Publication date: Available online 9 November 2019Source: Advances in Water ResourcesAuthor(s): Mohamed E. Ammar, Amr Gharib, Zahidul Islam, Evan G.R. Davies, Michael Seneka, Monireh FaramarziAbstractNonstationary flood frequency analysis (NFFA) has increasingly been applied to predict future floods under climate change. The inference of nonstationarity from trend tests (INTT) on historical floods is a widespread practice used to justify the application of NFFA; however, its reliability has seldom been investigated. This research examines future floods from interpretations of INTT compared to those obtained from cause-and-effect processes by a hydrological model (INCE). The study uses INCE to quantify the changes in the regime and magnitude of floods due to potential climate change in the mid-21st century using multi-model ensemble simulations under two greenhouse gas emissions scenarios (i.e., RCP 2.6 and RCP 8.5). Independent peaks over threshold from simulated streamflow were used to estimate the changes in future (2040-2064) flood regimes and magnitudes compared to their historical (1983-2007) counterparts for 29 unregulated catchments across Alberta, Canada. Separation of extreme events and their fittings to generalized Pareto distributions (GPD) were based on a hybrid approach that combined two developed automated threshold selection methods and four estimators for the parameters of the GPD. Based on comparing the results of INTT and INCE, we show that future changes in floods contradict. We also show that the future frequency curves shifted differently at different return periods compared to historical curves, while in some instances, future climate tended to decrease small floods and increase larger floods or vice versa. Finally, flood magnitudes in 2/3 of the studied catchments in Alberta are predicted to intensify, accompanied by increases in the rate of occurrence and earlier shifts in the timing of floods for both climate scenarios, whereas no considerable change in the duration was recognized.
       
  • Taiwanese Rainfall Variability associated with Large-scale Climate
           Phenomena
    • Abstract: Publication date: Available online 7 November 2019Source: Advances in Water ResourcesAuthor(s): Jai Hong Lee, Chun-Yao Yang, Pierre Y. JulienAbstractExamining the physical mechanisms through which large scale climate indicators, e.g., El Niño-Southern Oscillation and Indian Ocean Dipole, affect hydroclimatic variables in the tropics and extratropics is a scientific challenge. In this study, climatic relationships between large-scale climate indices (CIs) and Taiwan rainfall variability were examined. Not only leading patterns of observed monthly total and extreme rainfall were estimated through an empirical orthogonal teleconnection method (EOT), but also correlation and regression analyses were performed for the leading rainfall patterns and various CIs based on atmospheric-ocean circulation dataset. From the spatial structure of the leading EOT patterns for total and extreme rainfall, the north-coast mode in the cold seasons and the middle-inland mode for the warm seasons were detected. The temporal cycle of the leading EOT patterns indicates decreasing trends in the cold seasons and oscillations mainly on decadal timescales in the warm seasons. The leading EOT patterns of total rainfall showed more widespread coherent patterns than those of extreme rainfall with more variance in rainfall variability. The findings from this study illustrate that tropical ENSO forcing has a coherent association with March and October-November rainfall patterns, while the Indian Ocean Dipole is identified as a driver for rainfall variability during spring and fall. The western North Pacific monsoon activity has a negative (positive) correlation with March (October and December) rainfall variabilities and tropical cyclone indices also exhibit significant positive correlation with October rainfalls. The leading patterns of the October and following-year March rainfall time series are predictable at up to nine-month lead time from the tropical Pacific sea surface temperatures (SSTs).
       
  • Numerical modeling of density-driven solute transport in fractured porous
           media with the extended finite element method
    • Abstract: Publication date: Available online 4 November 2019Source: Advances in Water ResourcesAuthor(s): N. Hosseini, Z. Bajalan, A.R. KhoeiAbstractIn this paper, a numerical model is developed based on the X-FEM technique to simulate the transport of dense solute in a single fluid phase through the fractured porous media. The governing equation is based on the mass conservation law which is applied to the fluid phase and the solute in both matrix and fracture domain. The integral governing equations of the mass exchange between the fracture and the surrounding matrix is derived. The extended finite element method (X-FEM) is applied by employing appropriate enrichment functions to model the fractured porous domain. The superiority of the X-FEM is that the FE mesh is not necessary to be conformed to the fracture geometry, so the regular mesh is utilized independent of the position of the fracture. Finally, several numerical examples of dense brine transport in a water aquifer are studied to validate the proposed computational algorithm. Moreover, the effects of various parameters of the fracture, such as the aperture and interconnectivity, as well as the matrix medium, such as the permeability and diffusion are investigated. It is shown that the proposed computational model provides an accurate prediction of subsurface hydrology for a field-scale closed desert basin.
       
  • On the integral and differential porosity models for urban flooding
           simulation
    • Abstract: Publication date: Available online 4 November 2019Source: Advances in Water ResourcesAuthor(s): Giada Varra, Veronica Pepe, Luigi Cimorelli, Renata Della Morte, Luca CozzolinoAbstractA novel differential porosity model for urban flooding, namely the Binary Single Porosity model (BSP), is proposed in the present paper. The BSP model, which is derived from the Single Porosity (SP) model by constraining the porosity to attain only the values zero inside the buildings and one in the voids among the buildings, is local and independent on the existence of a Representative Elementary Volume (REV). The BSP model satisfies the Galilean invariance, while the corresponding wave speeds are identical to those of the Shallow water Equations model, and its integral formulation coincides with the original integral model by Sanders et al. (2008).The structure of the BSP model implies that the solution of the SP Riemann problem is the numerical building block for the construction of the corresponding Finite Volume schemes. This observation prompts a further study of the SP model and its solutions, demonstrating that the exact SP Riemann problem solution has the potential to take into account the transient energy losses due to wave reflections through the urban fabric in BSP models. Nonetheless, a further comparison with the two-dimensional SWE results demonstrates that additional stationary energy dissipations must be accurately taken into account through porosity reductions in the case of supercritical flow. The numerical experiments show that available approximate SP Riemann solvers may cause a systematic underestimation of the energy dissipation through the urban fabric and an overestimation of the flood celerity. The improvement of SP Riemann solvers could limit the resort to additional drag and momentum dissipation terms that are frequently added in numerical models.Finally, the investigation of the differential porosity models where different definitions are used for storage and conveyance porosity shows that these models suffer from a fundamental lack of physical congruence, implying that they cannot be used for the analysis of flood wave propagation through urban fabric.
       
  • A spatially resolved fluid-solid interaction model for dense granular
           packs/Soft-Sand.
    • Abstract: Publication date: Available online 31 October 2019Source: Advances in Water ResourcesAuthor(s): Paula A. Gago, Ali Q. Raeini, Peter KingAbstractFluid flow through dense granular packs or soft sands can be described as a Darcy’ s flow for low injection rates, as the friction between grain-grain and grain-walls dominate the solid system behaviour. For high injection rates, fluid forces can generate grain displacement forming flow channels or “fractures”, which in turn modify local properties within the system, such as permeability and stress distribution. Due to this kind of “self organized” behaviour, a spatially resolved model for these interactions is required to capture the dynamics of these systems. In this work, we present a resolved model based on the approach taken by the CFDEM open source project which uses LIGGGHTS – a discrete elements method (DEM)– to model the granular behaviour and OpenFoam finite volume library for computational fluid dynamics (CFD), to simulate the fluid behaviour. The capabilities provided by the DEM engine allows the properties of the solid phase, such as inter-grain cohesion and solid confinement stress to be controlled. In this work the original solver provided by the CFDEM project was modified so as to deal with dense granular packs more effectively. Advantages of the approach presented are that it does not require external “scaling parameters” to reproduce well known properties of porous materials and that it inherits the performance provided by the CFDEM project. The model is validated by reproducing the well-known properties of static porous materials, such as its permeability as a function of the system porosity, and by calculating the drag coefficient for a sphere resting inside a uniform flow. Finally, we present fracture patterns obtained when modelling water injection into a Hele-Shaw cell, filled with a dense granular pack.
       
  • Bed morphodynamics at the intake of a side channel controlled by sill
           geometry
    • Abstract: Publication date: Available online 28 October 2019Source: Advances in Water ResourcesAuthor(s): T.V. de Ruijsscher, A.J.F. Hoitink, S. Naqshband, A.J. PaarlbergAs part of a general trend towards river management solutions that provide more room for the river, longitudinal training dams (LTDs) have recently been constructed in the inner bend of the Dutch Waal River, replacing groynes. LTDs split the river in a main channel and a bank-connected side channel with a sill at the entrance. In the present study, a physical scale model with mobile bed was used to study morphological patterns and discharge division in the entrance region of such a side channel. Alternative geometric designs of the sill are tested to investigate the controls on the diversion of water and sediment into the side channel. After reaching a morphodynamic equilibrium, two bar features were observed in the side channel under low flow conditions. An inner-bend depositional bar emerged against the LTD, resembling depositional bars observed in sharp river bends. A second bar occurred in the most upstream part of the side channel, next to the sill, induced by divergence of the flow by widening of the channel and an increasing flow depth after the sill, hence defined as a divergence bar. The morphologically most active system in the side channel emerges for the configuration in which the sill height decreases in downstream direction. For such a geometry, the sediment that settles during low flow is largely eroded during high flow, reducing maintenance needs. A qualitative comparison based on a lab experiment mimicking field conditions demonstrates the realism of the experiments.Graphical abstractGraphical abstract for this article
       
  • Multiscale induced polarization tomography in hydrogeophysics: a new
           approach
    • Abstract: Publication date: Available online 28 October 2019Source: Advances in Water ResourcesAuthor(s): A. Soueid Ahmed, A. Revil, L. GrossAbstractInduced polarization is a geophysical method that has gained ground in the last decade in hydrogeophysics. Yet the acquisition of high quality induced polarization data may be challenging using the current technologies mostly because of capacitive coupling effects especially for short durations in the injected current. In addition, making a true 3D induced polarization survey is very tedious and time consuming in field conditions. We discuss the advantages of a new generation of induced polarization equipment composed of individual stations able to measure the two components of the electric field along the ground surface. We show how this approach allows for integrating the whole data avoiding negative apparent resistivity/chargeability data. The use of decentralized recording stations solves the issue of capacitive coupling effects. We present a completely novel induced polarization data inversion methodology based on the measurement of the electric field components. In addition, a robust geostatistical inversion approach is discussed for recovering the conductivity and chargeability fields using the electric field components measured on the ground surface. We also treat the case of time lapse monitoring by using a low-rank Kalman filter approximation, which is computationally very appealing in terms of computational time and storage savings. The effectiveness of the new methodology is demonstrated on several realistic synthetic case studies. These numerical tests show that this electric field-based approach is robust and very promising for applications in hydrogeophysics.
       
  • Effects of Building Arrangement on Flow and Pressure Fields Generated by a
           Solitary Wave Interacting with Developed Coasts
    • Abstract: Publication date: Available online 23 October 2019Source: Advances in Water ResourcesAuthor(s): Erdinc Sogut, Deniz Velioglu Sogut, Ali FarhadzadehAbstractA series of laboratory experiments and Large-Eddy Simulation (LES) carried out to study the interactions of a solitary wave with arrays of blocks, representing idealized beachfront buildings, positioned at different arrangements show that formation of channelized flow between the blocks significantly alters the flow field, delays wave breaking and influences the total loading on the blocks in the back row. The staggered layout yields a 30 – 60% increase in the maximum force compared to the single-row and straight layouts due to impulsive loading, while the latter creates the highest shielding effect. The total number of vortices forming around the blocks is proportional to the number of sharp edges of the blocks. The dimensions of the vortex tubes are controlled by the width of the block. Although vorticities were not directly measured, the critical phenomena are accurately represented by the simulated flow field which was thoroughly validated using observations and measurements.
       
  • Homogeneity testing of multivariate hydrological records, using
           multivariate copula L-moments
    • Abstract: Publication date: Available online 19 October 2019Source: Advances in Water ResourcesAuthor(s): I. Ben Nasr, F. ChebanaAbstractRecently, there have been an increasing number of studies dealing with change detection in multivariate series. However, a major drawback with most of the currently used methods is the lack of flexibility. Indeed, these methods are only able to detect changes in the strength of dependence assuming invariant shape of the dependence structure. However, under a changing climate, the shape of dependence might change as well. Furthermore, in the multivariate setting, heterogeneities can occur in the margins and/or in the dependence structure. The most existing approaches for multivariate change detection deal with the whole distribution. In this paper, we propose a novel statistical test for multivariate heterogeneity detection, based on copula and multivariate L-moments. A simulation study is conducted to evaluate the performance of the proposed test and to compare it with those of existing tests. Results indicate that the proposed test has an interesting power especially when the dependence strength remains invariant, with power ranging between 45 and 93% whereas for the existing tests the power is lower than 14% in this case. An application to a real data set is also provided. Results show the ability of the proposed test to discriminate homogeneous and inhomogeneous series.
       
  • Tails of Extremes: Advancing a Graphical Method and Harnessing Big Data to
           Assess Precipitation Extremes
    • Abstract: Publication date: Available online 18 October 2019Source: Advances in Water ResourcesAuthor(s): Sofia Nerantzaki, Simon Michael PapalexiouAbstractExtremes are rare and unexpected. This limits observations and constrains our knowledge on their predictability and behavior. Graphical tools are among the many methods developed to study extremes. A major weakness is that they rely on visual-inspection inferences which are subjective and make applications to large datasets time-consuming and impractical. Here, we advance a graphical method, the so-called Mean Excess Function (MEF), into an algorithmic procedure. MEF investigates the mean value of a variable over threshold, and thus, focuses on extremes. We formulate precise and easy-to-apply statistical tests, based on the MEF, to assess if observed data can be described by exponential or heavier tails. As a real-world example, we apply our method in 21,348 daily precipitation records from all over the globe. Results show that the exponential-tail hypothesis is rejected in 75.8% of the records indicating that heavy-tail distributions (alternative hypothesis) can better describe rainfall extremes. The spatial variation of the tail heaviness reveals that heavy tails prevail in regions of Australia and Eurasia, with a “hot spot” found in central Russia and Kazakhstan. We deem this study offers a new diagnostic tool in assessing the behavior of extremes, easy to apply in large databases, and for any variable of interest. Our results on precipitation extremes reinforce past findings and further highlight that exponential tails should be used with caution.
       
  • An extension of data assimilation into the short-term hydrologic forecast
           for improved prediction reliability
    • Abstract: Publication date: Available online 11 October 2019Source: Advances in Water ResourcesAuthor(s): James M. Leach, Paulin CoulibalyAbstractTypically, when using data assimilation to improve hydrologic forecasting, observations are assimilated up to the start of the forecast. This is done to provide more accurate state and parameter estimates which, in turn, allows for a better forecast. We propose an extension to the traditional data assimilation approach which allows for assimilation to continue into the forecast to further improve the forecast's performance and reliability. This method was tested on two small, highly urbanized basins in southern Ontario, Canada; the Don River and Black Creek basins. Using a database of forcing data, model states, predicted streamflow, and streamflow observations, a lookup function was used to provide an observation during the forecast which can be assimilated. This allows for an indirect way to assimilate the numerical weather prediction forcing data. This approach can help in addressing prediction uncertainty, since an ensemble of previous observations can be pulled from the database which correspond to the forecast probability density function given previous information. The results show that extending data assimilation into the forecast can improve forecast performance in these urban basins, and it was shown that the forecast reliability could be improved by up to 78 percent.
       
  • Deeply Uncertain Pathways: Integrated Multi-City Regional Water Supply
           Infrastructure Investment and Portfolio Management
    • Abstract: Publication date: Available online 11 October 2019Source: Advances in Water ResourcesAuthor(s): B.C. Trindade, P.M. Reed, G.W. CharacklisAbstractThis study contributes the Deep Uncertainty (DU) Pathways framework for bridging long-term water supply infrastructure investments and improved short-term water portfolio management (e.g., restrictions, water transfers, financial instruments, etc.) to yield a regional water supply policy robust to supply and financial failures. The DU Pathways framework combines flexibility-providing risk-of-failure (ROF) decision rules, dynamic adaptive policy pathways concepts, and a careful consideration of time-evolving information feedbacks to yield management-conditioned infrastructure pathways for regions. The DU Pathways’ framework has been developed to carefully consider multi-actor regional contexts with the goal of aiding stakeholders in discovering pathway policies that attain high performance levels for supply reliability and financial stability across challenging, deeply uncertain futures and to guide robustness compromises that may be necessary between regional actors. As demonstrated in the Research Triangle region of North Carolina, DU Pathways clarifies how to identify robust infrastructure investment and management policies across the municipalities of Raleigh, Durham, Cary, and Chapel Hill. Our results provide insights about the most cost-effective infrastructure options to be pursued in the near-term, clarify which sources of uncertainty drive the performance tradeoffs and robustness conflicts across the regional system, and demonstrate valuable information on the diversity of interdependent failure modes that may emerge across the multiple actors implementing each candidate policy.
       
  • 2D numerical simulation of unsteady flows for large scale floods
           prediction in real time
    • Abstract: Publication date: Available online 9 October 2019Source: Advances in Water ResourcesAuthor(s): I. Echeverribar, M. Morales-Hernández, P. Brufau, P. García-NavarroAbstractThe challenge of finding a compromise between computational time and level of accuracy and robustness has traditionally expanded the use simplified models rather than full two-dimensional (2D) models for flood simulation. This work presents a GPU accelerated 2D shallow water model for the simulation of flood events in real time. In particular, an explicit first-order finite volume scheme is detailed to control the numerical instabilities that are likely to appear when used in complex topography. The model is first validated with the benchmark test case of the Toce River (Italy) and numerical fixes are demonstrated to be necessary. The model is next applied to reproduce real events in a reach of the Ebro River (Spain) in order to compare simulation results with field data. The second case deals with a large domain (744 km2) and long flood duration (up to 20 days) allowing an analysis of the performance and speed-up achieved by different GPU devices. The high values of fit between observed and simulated results as well as the computational times achieved are encouraging to propose the use of the model as forecasting system.
       
  • In Situ Pore-Scale Analysis of Oil Recovery During Three-Phase
           Near-Miscible CO2 Injection in a Water-Wet Carbonate Rock
    • Abstract: Publication date: Available online 8 October 2019Source: Advances in Water ResourcesAuthor(s): Abdulla Alhosani, Alessio Scanziani, Qingyang Lin, Ziqing Pan, Branko Bijeljic, Martin J. BluntAbstractWe study in situ three-phase near-miscible CO2 injection in a water-wet carbonate rock at elevated temperature and pressure using X-ray microtomography. We examine the recovery mechanisms, presence or absence of oil layers, pore occupancy and interfacial areas during a secondary gas injection process. In contrast to an equivalent immiscible system, we did not observe layers of oil sandwiched between gas in the centre of the pore space and water in the corners. At near-miscible conditions, the measured contact angle between oil and gas was approximately 73○, indicating only weak oil wettability in the presence of gas. Oil flows in the centres of large pores, rather than in layers for immiscible injection, when displaced by gas. This allows for a rapid production of oil since it is no longer confined to movement in thin layers. A significant recovery factor of 80% was obtained and the residual oil saturation existed as disconnected blobs in the corners of the pore space. At equilibrium, gas occupied the biggest pores, while oil and water occupied pores of varying sizes (small, medium and large). Again, this was different from an immiscible system, where water occupied only the smallest pores. We suggest that a double displacement mechanism, where gas displaces water that displaces oil is responsible for shuffling water into larger pores than that seen after initial oil injection. This is only possible since, in the absence of oil layers, gas can contact water directly. The gas-oil and oil-water interfacial areas are lower than in the immiscible case, since there are no oil layers and even water layers in the macro-pore space become disconnected; in contrast, there is a larger direct contact of oil to the solid. These results could serve as benchmarks for developing near-miscible pore-scale modelling tools.
       
  • ICAT: A numerical scheme to minimize numerical diffusion in
           advection-dispersion modeling and its application in identifying flow
           channeling
    • Abstract: Publication date: Available online 7 October 2019Source: Advances in Water ResourcesAuthor(s): Hui Wu, Pengcheng Fu, Joseph P. Morris, Randolph R. Settgast, Frederick J. RyersonAbstractThe advection-dispersion equation for scalar transport is essential for the numerical modeling of many fluid dynamics problems. However, solutions from numerical schemes always suffer from numerical diffusion and/or oscillation. In this study, we develop an Intra-Cell Advection Tracking (ICAT) scheme to minimize numerical diffusion and preserve monotonicity for advection-dispersion modeling. The key idea is to introduce “queues” in each discretized cell, and using a sequential transport rule and a flow distribution mechanism to track the scalar transport in these queues temporally and spatially. The capability and limitations of ICAT are first investigated through three test cases. Compared with the results obtained from other numerical schemes, the results from ICAT show substantially reduced numerical diffusion and agree better with analytical solutions. We also employ ICAT to simulate the transport process of a conservative tracer in a fracture with a highly heterogeneous aperture distribution. Discrete flow channels in the fracture are better discerned by ICAT than by other numerical schemes, indicating the suitability of ICAT for modeling tracer transport in channelized flow fields.
       
  • Copula-based modelling of earthen levee breach due to overtopping
    • Abstract: Publication date: Available online 7 October 2019Source: Advances in Water ResourcesAuthor(s): Matteo Balistrocchi, Giovanni Moretti, Stefano Orlandini, Roberto RanziAbstractThe level of protection offered by an earthen levee is typically described in terms of flood water level that the levee is capable of containing. If a larger flood occurs, floodwaters exceed the height of the levee and flow over its crest. As the water passes over the top, it may erode the levee, worsening the flooding and potentially causing a breach. In order to determine the annual probability that an earthen levee breaches due to overtopping, multiple flood characteristics such as peak flood water level, or related peak flow discharge, and flood duration need to be characterized statistically by using multivariate statistics. In this study, critical conditions for levee failure are described by using a Clayton copula relating peak flow discharge to flood duration. The obtained model is tested over a real river site located along the Panaro River, in northern Italy, where a 52-year time series of hourly flow discharge and a normal flow rating curve are available. The developed model makes it possible to delimitate the levee failure region within the population of flood events and to statistically describe earthen levee breach due to overtopping. Breach probability is found to be underestimated when the statistical association between peak flow discharge and flood duration is neglected. The proposed copula-based model is therefore important to support the design and construction of earthen levees, and to identify the actions needed to save lives and property when a flood exceeding the levee design limit occurs.
       
  • Linking parametric and water-balance models of the Budyko and Turc spaces
    • Abstract: Publication date: Available online 7 October 2019Source: Advances in Water ResourcesAuthor(s): Edoardo Daly, Salvatore Calabrese, Jun Yin, Amilcare PorporatoAbstractThe Budyko and Turc frameworks have become very popular tools for the estimation of catchment-scale water balance. In their original definition, these frameworks and the resulting equations, which are considered equivalent, apply in the long-term to very large catchments, whose water balance is predominately driven by climatic factors. Several equations similar to Budyko’s and Turc’s have subsequently been proposed to account also for the effect of catchment characteristics, including parametric formulations as well as equations resulting from a simplified physical representation of the water balance. After highlighting their advantages and disadvantages, we show that models based on the water balance, which account for rainfall variability and feedback between water availability and evapotranspiration, are more versatile to describe catchment-scale rainfall partitioning. They include parameters that have clearer physical meaning and, therefore, can be estimated independently of streamflow and evapotranspiration, thereby making them more amenable to practical use in un-gaged catchments. They show that Budyko’s and Turc’s point of view are equivalent only for large catchments. Additionally, water balance models have limiting conditions for extremely dry and wet climates that differ from those of the Budyko equations and its parametric formulations, as expected in catchments with a finite water storage capacity; in these models, Budykoâs and Turcâs points of view become equivalent only for large catchments.
       
  • Splitting-based domain decomposition methods for two-phase flow with
           different rock types
    • Abstract: Publication date: Available online 7 October 2019Source: Advances in Water ResourcesAuthor(s): Elyes AhmedAbstractIn this paper, we are concerned with the global pressure formulation of immiscible incompressible two-phase flow between different rock types. We develop for this problem two robust schemes based on domain decomposition (DD) methods and operator-splitting techniques. The first scheme follows a sequential procedure in which the (global) pressure, the saturation-advection and the saturation-diffusion problems are fully decoupled. In this scheme, each problem is treated individually using various DD approaches and specialized numerical methods. The coupling between the different problems is explicit and the time-marching is with no iterations. To adapt to different time scales of problem components and different rock types, the novel scheme uses a multirate time stepping strategy, by taking multiple finer time steps for saturation-advection within one coarse time step for saturation-diffusion and pressure, and permits independent time steps for the advection step in the different rocks. In the second scheme, we review the classical Implicit Pressure–Explicit Saturation (IMPES) method (by decoupling only pressure and saturation) in the context of multirate coupling schemes and nonconforming-in-time DD approaches. For the discretization, the saturation-advection problem is approximated with the explicit Euler method in time, and in space with the cell-centered finite volume method of first order of Godunov type. The saturation-diffusion problem is approximated in time with the implicit Euler method and in space with the mixed finite element method, as in the pressure problem. Finally, in a series of numerical experiments, we investigate the practicality of the proposed schemes, the accuracy-in-time of the multirate and nonconforming time strategies, and compare the convergence of various DD methods within each approach.
       
  • Assessing the sensitivity of hydro-climatological change detection methods
           to model uncertainty and bias
    • Abstract: Publication date: Available online 2 October 2019Source: Advances in Water ResourcesAuthor(s): Ze Jiang, Ashish Sharma, Fiona JohnsonAbstractDetection of systematic changes in the climate system resulting from anthropogenic forcing is a critical area of research. Detection and attribution of hydro-climatological change has been limited by model uncertainty and bias as well as the poor spatial-temporal coverage of observational data. This study assesses a routinely adopted detection methodology and its sensitivity to model uncertainty and bias within a hydro-climatological context. Using a synthetic case study, we establish the sensitivity of detection approaches to the magnitude and consistency of trend and variance along with the length of data available. It is found that the extent of uncertainty (as measured by the variance) plays a critical role in changing the detection outcome. Another important factor is the consistency of trend between simulations and observations. A case study of soil moisture in select locations within Australia shows that averaging over multiple years (e.g., five years to a decade) improves the detection of the climate change signal as long as consistency in the trends exists. Our results also demonstrate that there are substantial differences in simulated trends across climate models. Therefore, even though ensemble averaging is effective in modulating variance, it has the risk of canceling out the signal over models with markedly different responses.
       
  • Crossover from anomalous to Fickean behavior in infiltration and reaction
           in fractal porous media
    • Abstract: Publication date: Available online 30 September 2019Source: Advances in Water ResourcesAuthor(s): F.D.A. Aarão ReisAbstractWhen the solution in a porous medium is in chemical equilibrium with mineral grains and an external surface is put in contact with water, the infiltration of unsaturated solution may be accompanied by mineral reactions that change the morphology of that medium. Here we study the evolution of this infiltration process considering that the initial porous media are fractal and that the reactions form additional porous material plus soluble products. A Sierpinski carpet and a Menger sponge are the fractal models, the mineral inclusions are represented by the non-fractal blocks (squares and cubes) formed in their iterative constructions, and reaction rates are described by a thermally activated model, in conditions of slow reactions in comparison with the diffusion. The interplay between the infiltration by diffusion and the structural changes by the reactions is explained by a combination of kinetic Monte Carlo simulations of lattice models and a scaling approach. At short times, the infiltration is subdiffusive, but the dissolved mass increases anomalously fast due to delocalization of the reaction, which is distributed through a time increasing infiltrated region. At long times, normal (Fickean) infiltration and reaction are observed. The crossover between the two regimes occurs when the thickness of the altered layer formed around the mineral inclusions is of the same order of magnitude of the width a of the smallest gaps between those inclusions. The order of magnitude of the crossover time tc is estimated as a/(vk), where k is the reaction rate constant and v is the molar volume of the mineral; this time does not depend on the diffusion coefficient of reaction products nor on the fractal geometry of the initial medium, which suggests the application to a variety of systems. Estimates of tc are obtained in two recently studied rocks with reported fractal properties and justify the Fickean diffusion assumption of previous models for their weathering in geological time scales. The morphological evolution of the mineral blocks that partially reacted qualitatively agrees with experiments.
       
  • Adaptation of the visibility graph algorithm for detecting time lag
           between rainfall and water level fluctuations in Lake Okeechobee
    • Abstract: Publication date: Available online 30 September 2019Source: Advances in Water ResourcesAuthor(s): Rahul John, Majnu JohnAbstractIdentifying time-lag between two hydrogeological time series for planning and management of water resources has a long history and is of continuing research interest. Many hydrogeological studies in the past have used visual inspection and cross-correlogram techniques in quantifying the time lag. Cross-correlogram techniques, if not done under the transfer function framework, could lead to ambiguous results. In order to conduct cross-correlogram analysis under the transfer function framework, careful pre-processing steps have to be undertaken, which are often ignored in practice. In this paper, we propose a new approach to compare two sets of hydrogeological time series data using a visibility graph algorithm and show the advantages of using the new approach over the traditional one. Application of the new approach is demonstrated by assessing the lags between rainfall and water level fluctuation in Lake Okeechobee, Florida. We also present simulation studies to better understand the performance of the method for different sample sizes, different underlying models and in the presence of missing values.
       
  • Multi-scale statistical properties of disaggregated SMOS soil moisture
           products in Australia
    • Abstract: Publication date: Available online 23 September 2019Source: Advances in Water ResourcesAuthor(s): M. Neuhauser, S. Verrier, O. Merlin, B. Molero, C. Suere, S. MangiarottiAbstractSoil moisture has a strong impact on climate, hydrology and agronomy at different space scales, from the continent global scale to the local watershed. Passive microwave sensors, like SMOS satellite (Soil Moisture and Ocean Salinity), allow a global study of soil moisture on the entire globe. To have access to kilometric variability, disaggregation algorithms have been developed, such as the Disaggregation based on Physical And Theoretical scale Change (DisPATCh). This method improves the space resolution of SMOS soil moisture from 40 km to 1 km. To do this, it combines coarse-scale (≈40 km) SMOS products with fine-scale (≈1 km) optical/thermal data. Validation studies on specific scales showed the potential of DisPATCh to enhance the spatio-temporal correlation of disaggregated SM with in-situ measurements, under low-vegetated semi-arid regions. Although the efficiency of the method was revealed in these regions, no studies fully explored its statistical behavior over a continuum of space scales. In this paper, we studied and compared the spatial multi-scale statistics of the different input and output datasets involved in DisPATCh downscaling. To do this, we applied spectral and multifractal analysis on the respective products for the region of southeastern Australia, from June to December 2010. Fractal and multifractal properties (in the framework of the Universal Multifractal model) were observed on inputs of DisPATCh (SMOS soil moisture, MODIS vegetation indices and surface temperature), which confirmed and completed some results reported in existing literature. For the output disaggregated soil moisture, two scaling regimes were observed, with a transition scale observed at about ten kilometers. Considering spectral analysis, at large scales (> 10 km), disaggregated soil moisture was found to have the same scaling as the original SMOS soil moisture. On finer scales (< 10 km), a different behavior was noticed, with a higher value of the slope of the power spectrum. The same scale break was detected on statistical moments, showing that both spectral and multifractal properties of DisPATCh soil moisture are characterized by this twofold scaling signature.
       
  • Rock properties from micro-CT images: digital rock transforms for
           resolution, pore volume, and field of view
    • Abstract: Publication date: Available online 10 September 2019Source: Advances in Water ResourcesAuthor(s): Dr Nishank Saxena, Amie Hows, Ronny Hofmann, Faruk O. Alpak, Jesse Dietderich, Matthias Appel, Justin Freeman, Hilko De JongAbstractDigital Rock Physics is a promising approach for achieving more, cheaper, and faster rock property characterization of digital images of rock samples. To successfully deliver on this potential, we must correctly interpret the digitally derived properties in the context of the limitations imposed by imaging constraints. To this end, we show that a combination of limited image resolution, a biased segmentation of images with coarse resolution, and a finite field of view of images, generated by the present micro-Computed Tomography (micro-CT) technology, leads to systematic underestimation of porosity (down to a factor of 0.5) and overestimation of permeability (up to a factor of 10) calculated using the Digital Rock Physics (DRP). We demonstrate these imaging limitations can be overcome by identifying good measures of image resolution and representative elementary volume and applying appropriate transforms. These transforms expand the operating envelop of DRP. Transforms for finite image resolution and limited field of view can be estimated directly from the micro-CT images. However, implementation of transforms related to errors in image segmentation require either a higher resolution image (e.g., nano-computed tomography, scanning electron microscopy) or laboratory measured constraints (Mercury injection capillary pressure, NMR porosity). Additionally, we suggest how insights from these transforms can be used to define operating envelopes and optimize imaging resolution and field of view to achieve more reliable results from digital rock characterization and simulations.
       
 
 
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