Download or read book Dynamics of Freshwater Plumes written by Derek Allen Fong and published by . This book was released on 1998 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: A freshwater plume often forms when a river or an estuary discharges water onto the continental shelf. Freshwater plumes are ubiquitous features of the coastal ocean and usually leave a striking signature in the coastal hydrography. The present study combines both hydrographic data and idealized numerical simulations to examine how ambient currents and winds influence the transport and mixing of plume waters. The first portion of the thesis considers the alongshore transport of freshwater using idealized numerical simulations. In the absence of any ambient current, the downstream coastal current only carries a fraction of the discharged fresh water; the remaining fraction recirculates in a continually growing "bulge" of fresh water in the vicinity of the river mouth. The fraction of fresh water transported in the coastal current is dependent on the source conditions at the river mouth. The presence of an ambient current augments the transport in the plume so that its freshwater transport matches the freshwater source. For any ambient current in the same direction as the geostrophic coastal current, the plume will evolve to a steady-state width. A key result is that an external forcing agent is required in order for the entire freshwater volume discharged by a river to be transported as a coastal current. The next section of the thesis addresses the wind-induced advection of a river plume, using hydrographic data collected in the western Gulf of Maine. The observations suggest that the plume's cross-shore structure varies markedly as a function of fluctuations in alongshore wind forcing. Consistent with Ekman dynamics, upwelling favorable winds spread the plume offshore, at times widening it to over 50 km in offshore extent, while downwelling favorable winds narrow the plume width to a few Rossby radii. Near-surface current meters show significant correlations between cross-shore currents and alongshore wind stress, consistent with Ekman theory. Estimates of the terms in the alongshore momentum equation calculated from moored current meter arrays also indicate an approximate Ekman balance within the plume. A significant correlation between alongshore currents and alongshore wind stress suggests that interfacial drag may be important. The final section of the thesis is an investigation of the advection and mixing of a surface-trapped river plume in the presence of an upwelling favorable wind stress, using a three-dimensional model in a simple, rectangular domain. Model simulations demonstrate that the plume thins and is advected offshore by the cross shore Ekman transport. The thinned plume is susceptible to significant mixing due to the vertically sheared horizontal currents. The first order plume response is explained by Ekman dynamics and a Richardson number mixing criterion. Under a sustained wind event, the plume evolves to a quasi-steady, uniform thickness. The rate of mixing slowly decreases for longer times as the stratification in the plume weakens, but mixing persists under a sustained upwelling wind until the plume is destroyed. Mixing is most intense at the seaward plume front due to an Ekman straining mechanism in which the advection of cross-shore salinity gradients balances vertical mixing. The mean mixing rate observed in the plume is consistent with the mixing power law suggested by previous studies of 1-D mixing, in spite of the two-dimensional dynamics driving the mixing in the plume

Download or read book Dynamics of Freshwater Plumes Observations and Numerical Modeling of the Wind Forced Response and Alongshore Freshwater Transport written by and published by . This book was released on 1998 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: A plume often results when a river discharges fresh water into the nearshore waters. This thesis combines both hydrographic data and idealized numerical simulations to examine how ambient currents and winds influence the transport and mixing of plume waters. The alongshore transport of freshwater is studied using a numerical model. In the absence of ambient currents, the downstream coastal current only carries a fraction of the discharged fresh water; the remaining fraction recirculates in a continually growing "bulge" in the vicinity of the river mouth. The presence of an ambient current augments the freshwater transport in the coastal current so that it matches the freshwater source. The thesis also studies the wind-induced advection and mixing of a river plume, using data collected in the western Gulf of Maine (GOM) and idealized numerical modeling experiments. The cross-shore structure of the GOM plume varies as a function of fluctuations in alongshore wind forcing. Estimates of the alongshore momentum balance indicate an approximate Ekman balance. The model simulations of a plume forced by upwelling winds demonstrate that the plume thins and is advected offshore by the cross-shore Ekman transport. The thinned plume is susceptible to significant mixing because of the sheared horizontal currents.

Download or read book Advances in Geosciences written by Jianping Gan and published by World Scientific. This book was released on 2009 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Geosciences is the result of a concerted effort to bring together the latest results and planning activities related to earth and space science in Asia and the international arena. The volume editors are all leading scientists in their research fields covering six sections: Atmospheric Science (AS), Hydrological Science (HS), Ocean Science (OS), Solid Earth (SE), Solar Terrestrial (ST) and Planetary Science (PS). The main purpose is to highlight the scientific issues essential to the study of earthquakes, tsunamis, atmospheric dust storms, climate change, drought, flood, typhoons, monsoons, space weather, and planetary exploration. This volume is abstracted in NASA''s Astrophysics Data System: http: //ads.harvard.edu. Contents: 3D Current Characteristics Simulation with ANN (C Z Chew et al.); Classification of Ocean Waves from the Data Buoy Measurements (R Balaji et al.); Intercomparison of Various Latent Heat Flux Products in the South China Sea (Zhen et al.); and other papers. Readership: Academics, researchers and postgraduate students in geosciences

Download or read book Advances In Geosciences A 6 volume Set Volume 12 Ocean Science Os written by Jianping Gan and published by World Scientific. This book was released on 2009-07-24 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Geosciences is the result of a concerted effort to bring together the latest results and planning activities related to earth and space science in Asia and the international arena. The volume editors are all leading scientists in their research fields covering six sections: Atmospheric Science (AS), Hydrological Science (HS), Ocean Science (OS), Solid Earth (SE), Solar Terrestrial (ST) and Planetary Science (PS). The main purpose is to highlight the scientific issues essential to the study of earthquakes, tsunamis, atmospheric dust storms, climate change, drought, flood, typhoons, monsoons, space weather, and planetary exploration.

Download or read book Contemporary Issues in Estuarine Physics written by Arnoldo Valle-Levinson and published by Cambridge University Press. This book was released on 2010-01-28 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Estuaries are of high socioeconomic importance with twenty-two of the thirty-two largest cities in the world located on river estuaries. Estuaries bring together fluxes of fresh and saline water, as well as fluvial and marine sediments, and contain high biological diversity. Increasingly sophisticated field observation technology and numerical modeling have produced significant advances in our understanding of the physical properties of estuaries over the last decade. This book introduces a classification for estuaries before presenting the basic physics and hydrodynamics of estuarine circulation and the various factors that modify it in time and space. It then covers special topics at the forefront of research such as turbulence, fronts in estuaries and continental shelves, low inflow estuaries, and implications of estuarine transport for water quality. Written by leading authorities on estuarine and lagoon hydrodynamics, this volume provides a concise foundation for academic researchers, advanced students and coastal resource managers.

Download or read book Journal of Physical Oceanography written by and published by . This book was released on 2005 with total page 1410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coastal Environment Disaster and Infrastructure written by X. San Liang and published by BoD – Books on Demand. This book was released on 2018-11-14 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coastal environment is deteriorating at an alarming rate and is currently a great societal concern. This book provides a selected collection of papers on coastal environmental change, coastal disasters, and coastal infrastructure due to global warming, with a focus on the coasts of the rapidly developing country China. What makes the book distinctly different from others is its diversity, reflecting the interdisciplinary nature of coastal problems. With contributions from over 30 authors, the book is a comprehensive account of diverse topics, such as coastal upwelling, estuarine processes, coastal pollution, sea level rise, meteorological and atmospheric problems, urbanization and the heat island effect, and coastal infrastructure, to name just a few, from theoretical study and phenomenological description, to methodological development. This book is expected to serve as a relatively comprehensive reference for coastal researchers, graduate students, as well as policymakers and coastal resource managers.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2000 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Environmental Fluid Dynamics Volume One written by Harindra Joseph Fernando and published by CRC Press. This book was released on 2012-12-12 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: With major implications for applied physics, engineering, and the natural and social sciences, the rapidly growing area of environmental fluid dynamics focuses on the interactions of human activities, environment, and fluid motion. A landmark for the field, the two-volume Handbook of Environmental Fluid Dynamics presents the basic principles, fundamental flow processes, modeling techniques, and measurement methods used in the study of environmental motions. It also offers critical discussions of environmental sustainability related to engineering. The handbook features 81 chapters written by 135 renowned researchers from around the world. Covering environmental, policy, biological, and chemical aspects, it tackles important cross-disciplinary topics such as sustainability, ecology, pollution, micrometeorology, and limnology. Volume One: Overview and Fundamentals provides a comprehensive overview of the basic principles. It starts with general topics that emphasize the relevance of environmental fluid dynamics research in society, public policy, infrastructure, quality of life, security, and the law. It then discusses established and emerging focus areas. The volume also examines the sub-mesoscale flow processes and phenomena that form the building blocks of environmental motions, with emphasis on turbulent motions and their role in heat, momentum, and species transport. As communities face existential challenges posed by climate change, rapid urbanization, and scarcity of water and energy, the study of environmental fluid dynamics becomes increasingly relevant. This volume is a valuable resource for students, researchers, and policymakers working to better understand the fundamentals of environmental motions and how they affect and are influenced by anthropogenic activities. See also Handbook of Environmental Fluid Dynamics, Two-Volume Set and Volume Two: Systems, Pollution, Modeling, and Measurements.

Download or read book Handbook of Environmental Fluid Dynamics Two Volume Set written by Harindra Joseph Fernando and published by CRC Press. This book was released on 2012-12-11 with total page 1197 pages. Available in PDF, EPUB and Kindle. Book excerpt: With major implications for applied physics, engineering, and the natural and social sciences, the rapidly growing area of environmental fluid dynamics focuses on the interactions of human activities, environment, and fluid motion. A landmark for the field, this two-volume handbook presents the basic principles, fundamental flow processes, modeling techniques, and measurement methods used in the field, along with critical discussions of environmental sustainability related to engineering aspects. The first volume provides a comprehensive overview of the fundamentals, and the second volume explores the interactions between engineered structures and natural flows.

Download or read book Buoyancy Driven Flows written by Eric P. Chassignet and published by Cambridge University Press. This book was released on 2012-03-05 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes buoyancy-driven flows for advanced students and researchers in oceanography, geophysical fluid dynamics, atmospheric science and Earth science.

Download or read book Dynamics and Numerical Modeling of River Plumes in Lakes written by Navid Nekouee and published by . This book was released on 2010 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Models of the fate and transport of river plumes and the bacteria they carry into lakes are developed. They are needed to enable informed decisions about beach closures to avoid economic losses, and to help design water intakes and operate combined sewer overflow schemes to obviate exposure of the public to potential pathogens. This study advances our understanding of river plumes dynamics in coastal waters by means of field studies and numerical techniques. Extensive field measurements were carried out in the swimming seasons of 2006 and 2007 on the Grand River plume as it enters Lake Michigan. They included simultaneous aerial photography, measurements of lake physical properties, the addition of artificial tracers to track the plume, and bacterial sampling. Our observed results show more flow classes than included in previous studies (e.g. CORMIX). Onshore wind can have a significant effect on the plume and whether it impacts the shoreline. A new classification scheme based on the relative magnitude of plume-crossflow length scale and Richardson number based on the wind speed is devised. Previous studies on lateral spreading are complemented with a new relationship in the near field. The plume thickness decreased rapidly with distance from the river mouth and a new non-dimensional relationship to predict thickness is developed. Empirical near field models for surface buoyant plumes are reviewed and a near field trajectory and dilution model for large aspect ratio surface discharge channels is devised. Bacterial reductions due to dilution were generally small (less than 10:1) up to 4.5 km from the river mouth. E. coli decay rates were significantly affected by solar radiation and ranged from 0.2 to 2.2 day-1 which were within the range of previous studies in Lake Michigan. Total coliform survived longer than E. coli suggesting different die-off mechanisms. Mathematical models of the bacterial transport are developed that employ a nested modeling scheme to represent the 3D hydrodynamic processes of surface river discharges in the Great Lakes. A particle tracking model is used that provides the capability to track a decaying tracer and better quantify mixing due to turbulent diffusion. Particle tracking models have considerable advantages over gradient diffusion models in simulating bacterial behavior nearshore that results in an improved representation of bacteria diffusion, decay and transport. Due to the complexity and wide variation of the time and length scale of the hydrodynamic and turbulent processes in the near field (where plume mixing is dominated by initial momentum and buoyancy) and far field (where plume mixing is dominated by ambient turbulence), a coupling technique is adapted. The far field random walk particle tracking model incorporates the empirical near field model. It simulates the transport, diffusion and decay of bacteria as discrete particles and employs the near field output as the source and transports the particles based on ambient currents predicted by the 3D hydrodynamic model. The coupled model improves dilution predictions in the near field. The new techniques advance our knowledge of the nearshore fate and transport of bacteria in the Great Lakes and can be ultimately applied to the NOAA Great Lakes Coastal Forecasting System to provide a reliable prediction tool for bacterial transport in recreational waters."--Summary.

Download or read book Estuarine and Coastal Modeling written by and published by . This book was released on 2005 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Studies of the Coastal Circulation Off Northern California written by Julie Davis Pullen and published by . This book was released on 2000 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Penetration of Buoyancy Driven Current Due to a Wind Forced River Plume written by Seong-Ho Baek and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The long term response of a plume associated with freshwater penetration into ambient, ocean water under upwelling favorable winds is studied using the Regional Ocean Modeling System (ROMS) in an idealized domain. Three different cases were examined, including a shore perpendicular source and shore parallel source with steady winds, and a shore perpendicular source with oscillating alongshore winds. Freshwater flux is used to define plume penetration. Alongshore penetration of buoyant currents is proportional to freshwater input and inversely proportional to upwelling wind stress strength. Strong wind more quickly prevents fresh water's penetration. Under upwelling favorable winds, the plume is advected offshore by Ekman transport as well as upcoast by the mean flow. This causes the bulge to detach from the coast and move to upcoast and offshore with a 45 degree angle. The path of the bulge is roughly linear, and is independent of wind strength. The bulge speed has a linear relationship with the wind stress strength, and it matches the expected speed based on Ekman theory. Sinusoidal wind leads to sequential upwelling and downwelling events. The plume has an asymmetric response to upwelling and downwelling and fresh water flux is changed immediately by wind. During downwelling, the downcoast fresh water transport is greatest, while it is reduced during upwelling. Background mean flow in the downcoast direction substantially increases alongshore freshwater transport.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coastal Ocean Processes CoOP written by and published by . This book was released on 2000 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: