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Books > Earth & environment > Earth sciences > The hydrosphere > Oceanography (seas)
Discussing all aspects of offshore surveying in a single volume, this book provides all algorithms necessary to develop complete software suites, and gives a large number of quality control criteria. It is invaluable to professional surveyors, offshore engineers and geophysicists, providing them with a wealth of data in a single volume. It is also a valuable reference work for hydrographic surveyors, seismic navigators and operations geophysicists. This book brings together information on spheroids, datums, projections and binning; gives a complete listing of UKOOA P1/90 and P2/91 formats for data transfer; a field guide to the calibration of radio navigation systems and compasses, acoustic and laser measuring devices; GPS, including calibration, use and differential techniques; field manual for quality control of all aspects of offshore surveying; listing of typical specifications for inclusion in survey contracts; and a comprehensive glossary of relevant terms for offshore surveying.
This volume is one outcome of the 6th International Conference on Paleoceano graphy (ICP VI). The conference was held August 23-28, 1998 in Lisbon, Portugal. The meeting followed the traditional format of a small number of invited oral presentations complemented by a large number ofcontributed posters. Over 550 participants attended, representing thirty countries and nearly 450 posters were presented. The invited speakers addressed the main themes of the 5oral sessions. The session topics were: Polar-Tropical and Interhemisphere Linkages; Does the Ocean Cause, or Respond to, Abrupt Climatic Changes?; Biotic Responses to Major Paleoceanographic Changes; Past Warm Climates; and Innovations In Monitoring Ocean History. This is the first time in ICP history that the Conference Proceedings are published. The aim of the organisers with the publication of this book is two-fold: to provide a useful review of the field and to document the ideas/controversies raised during the con ference that may stimulate future work. The book reflects the initial intentions of the conference, but it is not a conven tional conference proceedings, given that the papers have been reviewed by formal exter nal referees. Each of the conference topics is introduced by a review article designed to summarize the state of the art in each theme followed by articles prepared by the invited speakers. As with most conference proceedings, each theme is covered heterogenously. Some topics have all the expected contributions, others are less well covered."
Fifteen years ago NATO organised a conference entitled 'Ocean Acoustic Modelling'. Many of its participants were again present at this variability workshop. One such participant. in concluding his 1975 paper, quoted the following from a 1972 literature survey: ' ... history presents a sad lack of communications between acousticians and oceanographers' Have we done any better in the last 15 years? We believe so, but only moderately. There is still a massive underdeveloped potential for acousticians and oceanographers to make significant progress together. Currently, the two camps talk together insufficiently even to avoid simple misun derstandings. such as those in Table 1. Table 1 Ocsanographic and acoustic jargon (from an idea by Pol/ardi Jargon Oceanographic use Acoustic use dbordB decibar (depth in m) decibel (energy level) PE primitive equations parabolic equations convergence zone converging currents converging rays (downwelling water) (high energy density) front thermohaline front wave, ray or time front speed water current speed sound propagation speed 1 The list goes on.
Carbon dioxide and other `greenhouse' gases are increasing in the atmosphere due to the burning of fossil fuels, the destruction of rain forests, etc., leading to predictions of a gradual global warming which will perturb the global biosphere. An important process which counters this trend toward potential climate change is the removal of carbon dioxide from the surface ocean by photosynthesis. This process packages carbon in phytoplankton which enter the food chain or sink into the deep sea. Their ultimate fate is a `rain' of organic debris out of the surface-mixed layer of the ocean. On a global scale, the mechanisms and overall rate of this process are poorly known. The authors of the 25 papers in this volume present their state-of-the-art approaches to quantifying the mechanisms by which the `rain' of biogenic debris nourishes deep ocean life. Prominent deep sea ecologists, geochemists and modelers address relationships between data and models of carbon fluxes and food chains in the deep ocean. An attempt is made to estimate the fate of carbon in the deep sea on a global scale by summing up the utilization of organic matter among all the populations of the abyssal biosphere. Comparisons are made between these ecological approaches and estimates of geochemical fluxes based on sediment trapping, one-dimensional geochemical models and horizontal (physical) input from continental margins. Planning interdisciplinary enterprises between geochemists and ecologists, including new field programs, are summarized in the final chapter. The summary includes a list of the important gaps in understanding which must be addressed before the role of the deep-sea biota in global-scale processes can be put in perspective.
This symposium continues a long tradition for IUGGjIUTAM symposia going back to "Fundamental Problems in Thrbulence and their Relation to Geophysics" Marseille, 1961. The five topics that were emphasized were: turbulence modeling, statistics of small scales and coherent structures, con vective turbulence, stratified turbulence, and historical developments. The objective was to consider the ubiquitous nature of turbulence in a variety of geophysical problems and related flows. Some history of the contribu tions of NCAR and its alumni were discussed, including those of Jackson R Herring, who has been a central figure at NCAR since 1972. To the original topics we added rotation, which appeared in many places. This includes rotating stratified turbulence, rotating convective turbulence, horizontal rotation that appears in flows over terrain and the role of small scale vorticity in many flows. These complicated flows have recently begun to be simulated by several groups from around the world and this meeting provided them with an excellent forum for exchanging results, plus inter actions with those doing more fundamental work on rotating stratified and convective flows. New work on double diffusive convection was given in two presentations. The history of Large Eddy Simulations was presented and several new approaches to this field were given. This meeting also spawned some interesting interactions between observational side and how to inter pret the observations with modeling and simulations around the theme of particle dispersion in these flows.
Lake Mendota has often been called "the most studied lake in the world. " Beginning in the "classic" period of limnology in the late 19th century and continuing through the present time, this lake has been the subject of a wide variety of studies. Although many of these studies have been published in accessible journals, a significant number have appeared in local monographs and reports, ephemeral documents, or poorly distributed journals. To date, there has been no attempt at a synthetic treatment ofthe vast amount of work that has been published. One intent of the present book is to present a com prehensive compilation of the major early studies on Lake Mendota and to examine how they impinge on important present-day biological questions. In addition, this book presents a summary of field and laboratory work carried out in my own laboratory over a period of about 6 years and shows where correlations with earlier work exist. The book should be ofinterest to limnologists desiring a ready reference to data and published papers on this important lake, to biogeochemists, ocean ographers, and low-temperature geochemists interested in lakes as model sys tems for global processes, and to lake managers interested in understanding short-term and long-term changes in lake systems. Although the major thrust ofthe present book is ecologicaland environmental, sufficient background has been presented on other aspects ofLake Mendota's limnology so that the book should also be useful to nonbiologists."
Sedimentary coasts with their unique forms of life and productive
ecosystems are one of the most threatened parts of the
biosphere.
Paleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes, global and regional oceanography, and the cycles of biochemical components in the ocean. These prox ies are measurable descriptors for desired but unobservable environmental variables such as tempera ture, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The proxies are employed in a manner analogous to oceanographic methods. The water masses are first characterized according to their specific physical and chemical properties, and then related to particular assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing series of proven proxies available. Marine microfossil assemblages, for instance, are employed to reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorgan isms contain a wealth of paleoceanographic information in their isotopic and elemental compositions. Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to water temperatures, to cite a few examples. Organic material may also provide valuable infonnation, e. g. , about past productivity conditions. Studying the stable carbon isotope composition of bulk organic matter or individual marine organic components may provide a measure of past surface-water CO 2 conditions within the bounds of certain assumptions. Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving and improving, while new proxies are being studied and developed. The methodology is improved by analysis of samples from the water column and surface sediments, and through laboratory experiments.
Oceanographic discontinuities (e. g. frontal systems, upwelling areas, ice edges) are often areas of enhanced biological productivity. Considerable research on the physics and biology of the physical boundaries defining these discontinues has been accomplished (see [I D. The interface between water and sediment is the largest physical boundary in the ocean, but has not received a proportionate degree of attention. The purpose of the Nato Advanced Research Workshop (ARW) was to focus on soft-sediment systems by identifying deficiencies in our knowledge of these systems and defining key issues in the management of coastal sedimentary habitats. Marine sediments play important roles in the marine ecosystem and the biosphere. They provide food and habitat for many marine organisms, some of which are commercially important. More importantly from a global perspective, marine sediments also provide "ecosystem goods and services" [2J. Organic matter from primary production in the water column and contaminants scavenged by particles accumulate in sediments where their fate is determined by sediment processes such as bioturbation and biogeochemical cycling. Nutrients are regenerated and contaminants degraded in sediments. Under some conditions, carbon accumulates in coastal and shelf sediments and may by removed from the carbon cycle for millions of years, having a potentially significant impact on global climate change. Sediments also protect coasts. The economic value of services provided by coastal areas has recently been estimated to be on the order of $12,568 9 10 y" [3J, far in excess of the global GNP.
Rifted Ocean-Continent Boundaries covers a wide range of topics, from quantitative modelling to current knowledge of the structure and evolution of specific margins around the world. Special emphasis is placed on the structure and evolution of various Atlantic margins. After an introduction to volcanic margin concepts, the first articles report the results of numerical models of the mechanics of rift propagation, melt generation and sources of extensional stresses that may cause break-up. One part of the book is dedicated to current knowledge of the structure and evolution of various Atlantic margins. After a brief incursion into the Mediterranean, succeeding articles report on the transform and active margins of the Ivory Coast-Ghana transform margin and the Sea of Japan.
As part of its continuing program to stimulate superior basic research in the marine environment, the Office of Naval Research, Ocean Science and Technology Division, sponsored a series of closed seminar-workshops in 1972-1973. Each seminar focused upon one re search area of marine geology which is relatively new and in need of a critical evaluation and accelerated support. The subjects areas chosen for the seminars were: 1. natural gases in marine sediments and their mode of distribution, 2. nephelometry and the optical properties of ocean waters, 3. physical and engineering properties of deep-sea sediments, and 4. physics of sound in marine sediments. The objectives of each seminar-workshop were to bring into sharper focus the state-of-the-science within each subject area, to effect some degree of coordination among the investigators working within each of these areas and to provide the Ocean Science and Technology Division guidance for national program support. This volume.contains most of the papers presented at the semi nar on the physical and engineering properties of deep-sea sediments. The seminar was held at Airlie House, Airlie, Virginia on April 24- 27, 1973 and was organized and chaired by A. Inderbitzen. The at tendees were invited from among the leading investigators in this field from both the engineering and scientific disciplines. Each attendee was requested to prepare a paper within his area of spe ciality."
The goals ofthe Symposium were to highlight advances in modelling ofatmosphere and ocean dynamics, to provide a forum where atmosphere and ocean scientists could present their latest research results and learn ofprogress and promising ideas in these allied disciplines; to facilitate interaction between theory and applications in atmosphere/ocean dynamics. These goals were seen to be especially important in view ofcurrent efforts to model climate requiring models which include interaction between atmosphere, ocean and land influences. Participants were delighted with the diversity ofthe scientific programme; the opportunity to meet fellow scientists from the other discipline (either atmosphere or ocean) with whom they do not normally interact through their own discipline; the opportunity to meet scientists from many countries other than their own; the opportunity to hear significant presentations (50 minutes) from the keynote speakers on a range ofrelevant topics. Certainly the goal ofcreating a forum for exchange between atmosphere and ocean scientists who need to input to create realistic models for climate prediction was achieved by the Symposium and this goal will hopefully be further advanced by the publication ofthese Proceedings.
The authors explain the rewarding results from the interdisciplinary collaboration between an environmental study group working on coastal ecosystems and effects of oil spills and applied mathematicians modelling wave motion on sandy beaches. By using the unified Navier-Stokes equations with a Bingham fluid model for spilled oil, multi-phase flow analysis were made. Decomposition of spilled oil by bacteria was simulated as a chemical reaction, and the theoretical and numerical analysis suggested a countermeasure to help reduce stress on coastal ecosystems. The new understanding of how ecosystems both depend upon, and help to determine, the nature of the shoreline demonstrates promising ways to better assist and exploit the regenerative powers inherent in nature.
Global warming, melting polar caps, rising sea levels and intensifying wave-current action, factors responsible for the alarming phenomena of coastal erosion on the one hand and adverse environmental impacts and the high cost of 'hard' protection schemes, on the other, have created interest in the detailed examination of the potential and range of applicability of the emerging and promising category of 'soft' shore protection methods. 'Soft' methods such as beach nourishment, submerged breakwaters, artificial reefs, gravity drain systems, floating breakwaters, plantations of hydrophylous shrubs or even dry branches, applied mostly during the past 20 years, are recognised as possessing technical, environmental and financial advantageous properties deserving more attention and further developmental experimentation than has occured hitherto. On the other hand, 'hard' shore protection methods such as seawalls, groins and detached breakwaters, artefacts borrowed from port design and construction technology, no matter how well designed and well implemented they may be, can hardly avoid intensification of the consequential erosive, often devastating, effects on the down-drift shores. Moreover, they often do not constitute environmentally and financially attractive solutions for long stretches of eroding shoreline. Engineers and scientists practising design and implementation of shore defence schemes have been aware for many years of the public demand for improved shore protection technologies. They are encouraging efforts that promise enrichment of those environmentally sound and financially attractive methods that can be safely applied.
High Performance Computing in the Geosciences surveys the state of the art of programs presently being developed which require high performance computing for their implementation, provides a guide for decision making in regard to computing directions in future numerical models, and provides an overview of future developments in massively parallel processing and their implications for numerical modelling in the geosciences.
Challenging problems involvrllg jet and plume phenomena are common to many areas of fundamental and applied scientific research, and an understanding of plume and jet behaviour is essential in many geophysical and industrial contexts. For example, in the field of meteorology, where pollutant dispersal takes place by means of atmospheric jets and plumes formed either naturally under conditions of convectively-driven flow in the atmospheric boundary layer, or anthropogenically by the release of pollutants from tall chimneys. In other fields of geophysics, buoyant plumes and jets are known to play important roles in oceanic mixing processes, both at the relatively large scale (as in deep water formation by convective sinking) and at the relatively small scale (as with plume formation beneath ice leads, for example). In the industrial context, the performances of many engineering systems are determined primarily by the behaviour of buoyant plumes and jets. For example, (i) in sea outfalls, where either sewage or thermal effluents are discharged into marine and/or freshwater environments, (ii) in solar ponds, where buoyant jets are released under density interfaces, (iii) in buildings, where thermally-generated plumes affect the air quality and ventilation properties of architectural environments, (iv) in rotating machinery where fluid jet~ are used for cooling purposes, and (v) in long road and rail tunnels, where safety and ventilation prcedures rely upon an understanding of the behaviour of buoyant jets. In many other engineering and oceanographic contexts, the properties of jets and plumes are of great importance.
To place this book in perspective it is useful for the reader to be aware of the recent history of the topic of underwater sound generation at the ocean surface by natural mechanisms. A meeting in Lerici, Italy in 1987 was convened within the NATO Advanced Research Workshop series, to bring together underwater acousticians and ocean hydrodynamicists to examine various mechanisms which generate sound naturally at the ocean surface. A record of that meeting was published in the NATO scientific publication series in 1988 under the title 'Sea Surface Sound'. That meeting was successful in inspiring and co ordinating both participants and non-attending colleagues to examine some key issues which were raised during the course of presentations and discussions. The understanding among those present was that another meeting should be convened 3 years hence to report and review progress in the subject. Accordingly the second conference was convened in Cambridge in 1990, whose proceedings are presented here. This volume represents a very gratifying increase in only a 3 year interval in our understanding of a number of physical processes which generate sound at the peripheries of oceans. In fact it represents both the acceleration of singular effort as well as the development of interdisciplinary sophistication and co-operation. The enthusiasm, goodwill, and intense scientific curiosity which characterized the Lerici meeting carried through to Cambridge. The collegial atmosphere established by the participants was perfectly timed to foster another major advance in studies of ocean surface sound.
Acoustic Signal Processing for Ocean Explortion has two major goals: (i) to present signal processing algorithms that take into account the models of acoustic propagation in the ocean and; (ii) to give a perspective of the broad set of techniques, problems, and applications arising in ocean exploration. The book discusses related issues and problems focused in model based acoustic signal processing methods. Besides addressing the problem of the propagation of acoustics in the ocean, it presents relevant acoustic signal processing methods like matched field processing, array processing, and localization and detection techniques. These more traditional contexts are herein enlarged to include imaging and mapping, and new signal representation models like time/frequency and wavelet transforms. Several applied aspects of these topics, such as the application of acoustics to fisheries, sea floor swath mapping by swath bathymetry and side scan sonar, autonomous underwater vehicles and communications in underwater are also considered.
In July 1972, the U.S. Office of Naval Research identified several areas that it interpreted as being of interest to the U.S. Navy. Four of these research areas were then selected for their special importance in understanding physical processes on the ocean floor. In some of these, a great wealth of data has accumulated over the past two or three decades, but controversy exists in the interpretation of the results. In others, new techniques have re cently been devised that could lead to the collection and synthesis of new information. There was yet a third area in which little study had been undertaken and the results available appeared of great potential importance. The latter subject constitutes the title of this volume. To assess the information available and to facilitate plans for further research in the fields of interest that had been identified, the U.S. Office of Naval Research sponsored four symposia. The first was held in November 1972 at the University of California Con ference Center, Lake Arrowhead. The title of the symposium was "Natural Gases in Marine Sediments and Their Mode of Distribution." Twenty lectures were presented over a three-day period. All but two participants at this symposium subsequently submitted papers, which are published in this volume. In addition, Dr. K.O. Emery, who did not attend the symposium, supplied a manuscript on a topic most re levant to the subject matter discussed."
This seminal book results from a NATO Advanced Research Workshop at the University of Cambridge with Russian co-directorship, enabling the first formal dialogue between NATO and Russia about security issues in the Arctic Ocean. Involving interdisciplinary participation with experts from 17 nations, including all of the Arctic states, this workshop itself reflects progress in Arctic cooperation and collaboration. Interests now are awakening globally to take advantage of extensive energy, shipping, fishing and tourism opportunities in the Arctic Ocean as it is being transformed from a permanent sea-ice cap to a seasonally ice-free sea. This environmental state-change is introducing inherent risks of political, economic and cultural instabilities that are centralized among the Arctic states and indigenous peoples with repercussions globally. Responding with urgency, environmental security is presented as an "integrated approach for assessing and responding to the risks as well as the opportunities generated by an environmental state-change." In this book - diverse perspectives on environmental security in the Arctic Ocean are shared in chapters from high-level diplomats, parliamentarians and government officials of Arctic and non-Arctic states; leaders of Arctic indigenous peoples organizations; international law advisors from Arctic states as well as the United Nations; directors of inter-governmental organizations and non-governmental organizations; managers of multi-national corporations; political scientists, historians and economists; along with Earth system scientists and oceanographers. Building on the "common arctic issues" of "sustainable development and environmental protection" established by the Arctic Council - environmental security offers an holistic approach to assess opportunities and risks as well as develop infrastructure responses with law of the sea as the key "international legal framework" to "promote the peaceful uses" of the Arctic Ocean. With vision for future generations, environmental security is a path to balance national interests and common interests in the Arctic Ocean for the lasting benefit of all.
This collection of 52 papers presents the state-of-the-art of Oceanology of China Seas, including Yellow Sea, East China Sea and South China Sea. The papers are published in two volumes comprising six parts: Volume 1: Physical Oceanography, Marine Chemistry and Marine Biology. Volume 2: Marine Geology, Coastal Research and Marine Physics and Technology. The purpose of this book is to introduce to the world the most representative research of Chinese oceanographers and provide marine developers with a significant reference work. For marine scientists and developers at oceanographic institutions, academia and naval research establishments. It will also be of value to the oil company geologist having an interest in the exploration of China Seas.
Tsunamis are primarily caused by earthquakes. Under favourable
geological conditions, when a large earthquake occurs below the sea
bed and the resultant rupture causes a vertical displacement of the
ocean bed, the entire column of water above it is displaced,
causing a tsunami. In the ocean, tsunamis do not reach great
heights but can travel at velocities of up to 1000 km/hour. As a
tsunami reaches shallow sea depths, there is a decrease in its
velocity and an increase in its height. Tsunamis are known to have
reached heights of several tens of meters and inundate several
kilometres inland from the shore. Tsunamis can also be caused by
displacement of substantial amounts of water by landslides,
volcanic eruptions, glacier calving and rarely by meteorite impacts
and nuclear tests in the ocean.
Shear waves and closely related interface waves (Rayleigh, Stoneley and Scholte) play an important role in many areas of engineering, geophysics and underwater acoustics. In some cases interest is focused on large-amplitude waves of low frequency such as those associ ated with earthquakes and nuclear explosions; in other cases low amplitude waves, which have often travelled great distances through the sediment, are of interest. Both low and high frequency shear and interface waves are often used for seafloor probing and sediment characterization. As a result of the wide spectrum of different interests, different disciplines have developed lines of research and a literature particularly suited to their own problems. For example water-column acousticians view the seafloor sediment as the lower boundary of their domain and are interested in shear and interface waves in the near bottom sediments mainly from the standpoint of how they influence absorption and reflection at this boundary. On the other hand, geophysicists seeking deep oil deposits are interested in the maximum penetration into the sediments and the tell-tale characteristics of the seismic waves that have encountered potential oil or gas bearing strata. In another area, geotechnical engineers use shear and interface waves to study soil properties necessary for the design and the siting of seafloor structures.
The future of the Common Fisheries Policy depends on progress in the relevant areas of research. This applies to the whole range of management decisions, where precise, reliable and complete data are essential to inform those who must decide on the pursuit of existing activities, especially in the area of maritime fisheries, and the development of promising new activities such as aquaculture. Every day the Director-General of DG XIV requires more and more information to prepare decisions which will affect the future of all those in the Community who are dependent on fishing and aquaculture. There is thus a high level of direct demand from DG XIV. Over and above this immediate and specific requirement for short- and medium-term applications, research affects the competitivity of the Community. This is one area which favours the collaboration across frontiers of all those who seek to advance knowledge. But although DG XIV is uniquely placed to appreciate the importance of research into fisheries and aquaculture, there is no question of succumbing to the temptation to directly control the scope of research or its conduct. The notion of subsidiarity can best be understood by examining the existing structures in the Member States. The Commission must act first and foremost as a catalyst, by promoting the circulation of information and the coordination of research programmes. |
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