Fluvial-Tidal Sedimentology provides information on the ‘Tidal-Fluvial Transition', the transition zone between river and tidal environments, and includes contributions that address some of the most fundamental research questions, including how the morphology of the tidal-fluvial transition zone evolves over short (days) and long (decadal) time periods and for different tidal and fluvial regimes, the structure of the river flow as it varies in its magnitude over tidal currents and how this changes at the mixing interface between fresh and saline water and at the turbidity maximum, the role of suspended sediment in controlling bathymetric change and bar growth and the role of fine-grained sediment (muds and flocs), whether it is possible to differentiate between ‘fluvial’ and ‘tidally’ influenced bedforms as preserved in bars and within the adjacent floodplain and what are the diagnostic sedimentary facies of tidal-fluvial deposits and how are these different from ‘pure’ fluvial and tidal deposits, amongst other topics. The book presents the latest research on the processes and deposits of the tidal-fluvial transition, documenting recent major field programs that have quantified the flow, sediment transport, and bed morphology in tidal-fluvial zones. It uses description of contemporary environments and ancient outcrop analogues to characterize the facies change through the tidal-fluvial transition.
Introduction to Geophysical Fluid Dynamics provides an introductory-level exploration of geophysical fluid dynamics (GFD), the principles governing air and water flows on large terrestrial scales. Physical principles are illustrated with the aid of the simplest existing models, and the computer methods are shown in juxtaposition with the equations to which they apply. It explores contemporary topics of climate dynamics and equatorial dynamics, including the Greenhouse Effect, global warming, and the El Nino Southern Oscillation.
Recent results from modeling and observational studies demonstrate that the tropical Atlantic is a critical region for processes that maintain the meridional overturning circulation, such as cross-equatorial exchanges, and for sea surface temperature variability that impacts on climate variability of the coupled tropical ocean/atmosphere system. The theme of this book is the inter-hemispheric and inter-gyre exchanges of heat, salt and fresh water, while its goal is to improve the knowledge of the tropical Atlantic dynamics and how it affects the global ocean. A clear understanding of the dynamics of processes that affect the flow of mass and heat between the southern and the northern hemispheres in the upper few hundred meters in the tropical Atlantic and of those associated to the ocean circulation or to surface signals, from decadal, inter-annual to mesoscale periods, becomes necessary to better evaluate their contribution to the interhemispheric mass exchange. These processes are believed to be largely responsible in driving the sea surface temperature, which in turn, is a critical parameter to investigate ocean-atmospheric interactions. Output produced by regional models is also used to complement the observations and to provide additional information on their spatial and temporal variability. The subtropical cells, by bringing water masses subducted in the subtropics to the equator, and zonal currents investigated here contribute to the interhemispheric water exchange. Special attention is also given to the warm and salty anticyclonic rings shed by the North Brazil Current, which are now known to have a much broader impact, not only on interhemispheric water mass transfer, but also on the environment of remote regions. Observations from different sources are blended together, are used to validate model outputs and are also assimilated into models to obtain a more complete and accurate picture of the oceanic circulation and of its time evolution.
Cohesive sediment, or mud, is encountered in most water bodies throughout the world. Often mud is a valuable resource, synonymous with fertile land, enriching the natural environment and used as an important building material. Yet mud also hinders navigation and consequently, dredging operations have been carried out since ancient times to safeguard navigation. Unfortunately, many mud deposits are now contaminated, endangering the eco-system and increasing the costs of dredging operations. The transport and fate of mud in the environment are still poorly understood and the need for basic research remains. This text contains the proceedings of the INTERCOH-2000 conference on progress in cohesive sediment research. It was the sixth in a series of conferences initially started by Professor Ashish Mehta in 1984 as a "Workshop on Cohesive Sediment Dynamics with Special Reference to the Processes in Estuaries". During these conferences the character of the first workshop has always been maintained, that is, small scale and dedicated to the physical and engineering aspects of cohesive sediments, without parallel sessions, but with ample time for discussions during and after the presentations, and followed by a book of proceedings containing thoroughly reviewed papers. INTERCOH-2000 was integrated with the final workshop of the COSINUS project. This project was carried out as a part of the European MAST-3 programme, and almost all European cohesive sediment workers were involved. INTERCOH-2000 focused on the behaviour and modelling of concentrated benthic suspensions, i.e. high-concentrated near-bed suspensions of cohesive sediment. Special attention was paid to: sediment - turbulence interaction; flocculation and settling velocity; high-concentrated mud suspensions; processes in the bed - consolidation; processes on the bed - erosion; field observations on mud dynamics; instrumentation; and numerical modelling.
While ocean waves are the most visible example of oceanic mixing processes, this macroscale mixing process represents but one end of the spectrum of mixing processes operating in the ocean. At the scale of a typical phytoplanktoic diatom or larval fish inhabiting these seas, the most important mixing processes occur on the molecular scale - at the scale of turbulence. Physical-biological interactions at this scale are of paramount importance to the productivity of the seas (fisheries) and the heat balance that controls large scale ocean climate phenomena such as El Niño and tornadoes. This book grew out of the need for a comprehensive treatment of the diverse elements of geophysical fluid flow at the microscale. Kantha and Clayson have arranged a logial exposition of the various mixing processes operating within and between the oceans and its boundaries with the atmosphere and ocean floor. The authors' intent is to develop a volume that would provide a comprehensive treatment of the fundamental elements of ocean mixing so that students, academics, and professional fluid dynamicists and oceanographers can access this essential information from one source. This volume will serve as both a valuable reference tool for mathematically inclined limnologists, oceanographers and fluid modelers.
Within this monograph a comprehensive and systematic knowledge on shallow-water hydrodynamics is presented. A two-dimensional system of shallow-water equations is analyzed, including the mathematical and mechanical backgrounds, the properties of the system and its solution. Also featured is a new mathematical simulation of shallow-water flows by compressible plane flows of a special virtual perfect gas, as well as practical algorithms such as FDM, FEM, and FVM. Some of these algorithms have been utilized in solving the system, while others have been utilized in various applied fields. An emphasis has been placed on several classes of high-performance difference schemes and boundary procedures which have found wide uses recently for solving the Euler equations of gas dynamics in aeronautical and aerospatial engineering. This book is constructed so that it may serve as a handbook for practicians. It will be of interest to scientists, designers, teachers, postgraduates and professionals in hydraulic, marine, and environmental engineering; especially those involved in the mathematical modelling of shallow-water bodies.
This book contains articles presenting current knowledge about the formation and renewal of deep waters in the ocean. These articles were presented at an international workshop at the Naval Postgraduate School in Monterey in March 1990. It is the first book entirely devoted to the topic of deep water formation in which articles have been both selected and reviewed, and it is also the first time authors have addressed both surface and deep mixed layers. Highlighted are: past and recent observations (description and analysis), concepts and models, and modern techniques for future research. Thanks to spectacular advances realised in computing sciences over the last twenty years this volume includes a number of sophisticated numerical models. Observational as well as theoretical studies are presented and a clear distinction is established between open-ocean deep convection and shelf processes, both leading to deep- and bottom-water formation. The main subject addressed is the physical mechanism by which the deep water in the ocean can be renewed. Ventilation occurs at the surface in areas called the gills, where water is mixed and oxygenated before sinking and spreading in the abyss of the deep ocean. This phenomenon is a very active area for both experimentalists and theoreticians because of its strong implications for the understanding of the world ocean circulation and Earth climate. This major theme sheds light on specific and complex processes happening in very restricted areas still controlling three quarters of the total volume of the ocean. All articles include illustrations and a bibliography. This book will be of particular interest to physical oceanographers, earth scientists, environmentalists and climatologists.