Download or read book A Quasigeostrophic Eddy Resolving Model of the Antarctic Circumpolar Current written by Fred Kruse and published by . This book was released on 1990 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Eddy Diffusivities from a Doubly periodic Quasi geostrophic Model of the Antarctic Circumpolar Current written by Claire Murray and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Antarctic Circumpolar Current (ACC), long recognized for its importance in world ocean and climate dynamics, is close to purely zonal in many regions. This means the majority of meridional transport of heat or other scalars is largely achieved by transient mesoscale eddies. Many long-running climate models are still unable to resolve the mesoscale; their effects are parameterized, most commonly using the GM90 parameterization which relates mass transport to the slopes of isopycnal layers via an eddy diffusivity. In this project, the ACC was modelled using a two-layer quasi-geostrophic model with idealistic topography. A series of simulations were carried out with a combination of topography heights and forcing strengths. Time-mean statistics were used to fit several forms of the eddy diffusivity. A paradox was found in the cross-jet diffusivity. In a global sense, it increased as the strength of forcing and jet velocities increased, consistent with higher eddy kinetic energy. On the other hand, a local definition was found to be a local minimum in the jet core where the velocity peaked, consistent with research suggesting the ACC cores suppress mixing. In addition, a skew diffusivity was fitted and found to be globally non-zero for the higher topography, corresponding to a net eastwards flux. For the ridge simulations, large-scale variation in the cross and skew eddy diffusivity was noted and attributed to the effect of local bottom topography on baroclinic instability. This motivated a matrix definition of the eddy diffusivity, which included the bottom topography gradient as an additional parameter to estimate along and cross jet mass fluxes. In all forms the cross-jet diffusivity showed a large dependence on the density gradient. " --

Download or read book Dynamics of a Quasigeostrophic Antarctic Circumpolar Current written by Louis-Philippe Nadeau and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Representation of Eddies in Climate Models by a Potential Vorticity Flux written by Richard M. Wardle and published by . This book was released on 1999 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis addresses the parameterization of the heat and momentum transporting properties of eddy motions for use in primitive equation climate models. The approach is to transform the primitive equations to yield the altered.

Download or read book Ocean Modeling in an Eddying Regime written by Matthew W. Hecht and published by John Wiley & Sons. This book was released on 2013-04-30 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 177. This monograph is the first to survey progress in realistic simulation in a strongly eddying regime made possible by recent increases in computational capability. Its contributors comprise the leading researchers in this important and constantly evolving field. Divided into three parts Oceanographic Processes and Regimes: Fundamental Questions Ocean Dynamics and State: From Regional to Global Scale, and Modeling at the Mesoscale: State of the Art and Future Directions The volume details important advances in physical oceanography based on eddy resolving ocean modeling. It captures the state of the art and discusses issues that ocean modelers must consider in order to effectively contribute to advancing current knowledge, from subtleties of the underlying fluid dynamical equations to meaningful comparison with oceanographic observations and leading-edge model development. It summarizes many of the important results which have emerged from ocean modeling in an eddying regime, for those interested broadly in the physical science. More technical topics are intended to address the concerns of those actively working in the field.

Download or read book Modelling Oceanic Climate Interactions written by Jürgen Willebrand and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean plays a central role in determining the climate of the earth. The oceanic circulation largely controls the temporal evolution of cli mate changes resulting from human activities such as the increase of greenhouse gases in the atmosphere, and also affects the magnitude and regional distribution of those changes. On interannual and longer time scales the ocean is, through its interaction with the atmosphere, a source of important natural climate variations which we are only now beginning to recognise but whose cause has yet to be properly determined. Chem ical and biological processes in the ocean are linked to climate change, particularly through interaction with the global carbon cycle. A quantitative understanding of the oceanic role in the climate system requires models which include many complex processes and interactions, and which are systematically verified with observations. This is the ob jective of global research programs such as TOGA, WOCE, and JGOFS. Coupled numerical models of the oceanic and atmospheric circulation constitute the basis of every climate simulation. Increasingly it is recog nized that in addition a biological/chemical component is necessary to capture the pathways of carbon and other trace gases. The development of such coupled models is a challenging task which needs scientists who must be cognizant of several other disciplines beyond their own specialty.

Download or read book Mesoscale Synoptic Coherent Structures in Geophysical Turbulence written by B.M. Jamart and published by Elsevier. This book was released on 1989-07-01 with total page 859 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 20th Liège Colloquium was particularly well attended and these proceedings demonstrate the significant progress achieved in understanding, modelling, and observing geostrophic and near-geostrophic turbulence. The book contains more than 50 review papers and original contributions covering most aspects of the field of mesoscale/synoptic coherent structures in geophysical (oceanographic) turbulence. The properties of isolated vortices (generation, evolution, decay), their interactions with other vortices, with larger scale currents and/or with topography are investigated theoretically and by means of numerical and physical models. Observation of these dynamically important features in different parts of the world ocean are reported. Of particular interest will be the fourteen contributions by scientists from the USSR which emphasize the international character of the meeting. The book thus constitutes a useful and complete overview of the current state-of-the-art.

Download or read book Dynamics of the Antarctic Circumpolar Current written by Sarah Tragler Gille and published by . This book was released on 1995 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geosat altimeter data and numerical model output are used to examine the circulation and dynamics of the Antarctic Circumpolar Current (ACC). The mean sea surface height across the ACC has been reconstructed from height variability measured by the Geosat altimeter, without assuming prior knowledge of the geoid. For this study, an automated technique has been developed to estimate mean sea surface height for each satellite ground track using a meandering Gaussian jet model, and errors have been estimated using Monte Carlo simulation. The results are objectively mapped to produce a picture of the mean Subantarctic and Polar Fronts, which together comprise the major components of the ACC. The locations of the fronts are consistent with in situ observations and indicate that the fronts are substantially steered by bathymetry. The jets have an average Gaussian width of about 44 km in the meridional direction and meander about 75 km to either side of their mean locations. The width of the fronts is proportional to 1/f, indicating that with constant stratification, the width is proportional to the baroclinic. Rossby radius. The average height difference across the Subantarctic Front (SAF) is 0.7 m and across the Polar Front (PF) 0.6 m. The mean widths of the fronts are correlated with the size of the baroclinic Rossby radius. The meandering jet model explains between 40% and 70% of the height variance along the jet axes. Bathymetric constrictions are associated with increased eddy variability, a smaller percentage of which may be explained by the meandering of the ACC fronts, indicating that propagating eddies and rings may be spawned at topographic features. Detailed examination of spatial and temporal variability in the altimeter data indicates a spatial decorrelation scale of 85 km and a temporal e-folding scale of 34 days. The sea surface height variability is objectively mapped using these scales to define autocovariance functions. The resulting maps indicate substantial evidence of mesoscale eddy activity. Over 17-day time intervals, meanders of the PF and SAF appear to elongate, break off as rings, and propagate. Statistical analysis of ACC variability from altimeter data is conducted using empirical orthogonal functions (EOFs). The first mode EOF describes 16% of the variance in total sea surface height across the ACC; reducing the domain into basin scales does not significantly increase the variance represented by the first EOF, suggesting that the scales of motion are relatively short, and may be determined by local instability mechanisms rather than larger basin scale processes. Likewise, frequency domain EOFs indicate no statistically significant traveling wave modes. The momentum balance of the ACC has been investigated using both output from a high resolution primitive equation model and sea surface height measurements from the Geosat altimeter. In the Semtner-Chervin general circulation model, run with approximately quarter-degree resolution and time varying ECMWF winds, topographic form stress is the dominant process balancing the surface wind forcing. Detailed examination of form stress in the model indicates that it is due to three large topographic obstructions located at Kerguelen Island, Campbell Plateau, and Drake Passage. In order to reduce the effects of standing eddies, the model momentum balance is considered in stream coordinates; vertically integrated through the entire water column, topographic form drag is the dominant balance for wind stress. However, at mid-depth the cross-stream momentum transfer is dominated by horizontal biharmonic friction. In the upper ocean, horizontal friction, mean momentum flux divergence, transient momentum flux divergence, and mean vertical flux divergence all contribute significantly to the momentum balance. Although the relative importance of individual terms in the momentum balance does not vary substantially along streamlines, elevated levels of eddy kinetic energy are associated with the three major topographic features. In contrast, altimeter data show elevated energy levels at many more topographic features of intermediate scales, suggesting that smaller topographic effects are better able to communicate with the surface in the real ocean than in the model. Transient Reynolds stress terms play a small role in the the overall momentum balance; nonetheless, altimeter and model measurements closely agree, and suggest that transient eddies tend to accelerate the mean flow, except in the region between the major fronts which comprise the ACC. Potential vorticity is considered in the model output along Montgomery streamfunction. Even at about 1000 m depth, it varies in response to wind forcing, largely as a result of changes in vertical stratification, indicating that forcing and dissipation do not locally balance in the Southern Ocean. In order to compare model and altimeter potential vorticity estimates, two different proxies for potential vorticity on surface streamlines are considered. Both proxies show very similar results for model and altimeter, suggesting that differences in surface streamlines estimated by the altimeter and the model are not significant in explaining the Southern Ocean flow. The proxies are both roughly conserved along surface height contours but undergo substantial jumps near topographic features. However, they cannot capture stratification changes which may be critically important to the overall potential vorticity balance.

Download or read book Mesoscale Eddy Transport Across the Antarctic Circumpolar Current written by Audrey-Anne Gauthier and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Physical Oceanography written by and published by . This book was released on 2001-04 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric and Oceanic Fluid Dynamics written by Geoffrey K. Vallis and published by Cambridge University Press. This book was released on 2006-11-06 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid dynamics is fundamental to our understanding of the atmosphere and oceans. Although many of the same principles of fluid dynamics apply to both the atmosphere and oceans, textbooks tend to concentrate on the atmosphere, the ocean, or the theory of geophysical fluid dynamics (GFD). This textbook provides a comprehensive unified treatment of atmospheric and oceanic fluid dynamics. The book introduces the fundamentals of geophysical fluid dynamics, including rotation and stratification, vorticity and potential vorticity, and scaling and approximations. It discusses baroclinic and barotropic instabilities, wave-mean flow interactions and turbulence, and the general circulation of the atmosphere and ocean. Student problems and exercises are included at the end of each chapter. Atmospheric and Oceanic Fluid Dynamics: Fundamentals and Large-Scale Circulation will be an invaluable graduate textbook on advanced courses in GFD, meteorology, atmospheric science and oceanography, and an excellent review volume for researchers. Additional resources are available at www.cambridge.org/9780521849692.

Download or read book Satellite Altimetry and Earth Sciences written by Lee-Lueng Fu and published by Elsevier. This book was released on 2000-11-09 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: The new level of precision and global coverage provided by satellite altimetry is rapidly advancing studies of ocean circulation. It allows for new insights into marine geodesy, ice sheet movements, plate tectonics, and for the first time provides high-resolution bathymetry for previously unmapped regions of our watery planet and crucial information on the large-scale ocean features on intra-season to interannual time scales. Satellite Altimetry and Earth Sciences has integrated the expertise of the leading international researchers to demonstrate the techniques, missions, and accuracy of satellite altimetry, including altimeter measurements, orbit determination, and ocean circulation models.Satellite altimetry is helping to advance studies of ocean circulation, tides, sea level, surface waves and allowing new insights into marine geodesy. Satellite Altimetry and Earth Sciences provides high resolution bathymetry for previously unmapped regions of our watery planet.Satellite Altimetry and Earth Sciences is for a very broad spectrum of academics, graduate students, and researchers in geophysics, oceanography, and the space and earth sciences. International agencies that fund satellite-based research will also appreciate the handy reference on the applications of satellite altimetry.

Download or read book A Model Analysis of Potential Vorticity on Isopycnal Surfaces for the Global Ocean written by Douglas Craig Marble and published by . This book was released on 1993 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charts of potential vorticity (q) within four different density layers, calculated from an eddy resolving global ocean general circulation model, are presented for the Atlantic, Pacific, and Indian Ocean Basins. Potential Vorticity is evaluated as q = (f/p)*(delta sigma/delta z), a formulation that is valid for large, slow scales and allows it to be readily calculated from model output. Here, f is Coriolis, p in situ density, sigma the potential density referred to the sea surface, and z the vertical coordinate. The model is shown to represent oceanic density structure with reasonable accuracy. The most significant departure from observations are the steep density gradients on the northern boundary of the Antarctic Circumpolar Current. This may be due to model convective adjustment parameterizations and the extent of the smoothing in the cataloged data, which may be greater in the southern oceans due to relatively scarce observations. Model derived values of potential vorticity correspond well with those calculated from observations. In the middle and lower layers, the three basins tend toward homogenization, representing unventilated layers. Gyres of q in the upper layers of the northern Atlantic and Pacific Oceans, with their northern boundaries anchored in the outcrop region, illustrate the ventilation of these layers.

Download or read book Oceanic Circulation Models Combining Data and Dynamics written by D.L.T. Anderson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book which is the outcome of a NATO-Advanced Study Institute on Mod elling the Ocean Circulation and Geochemical Tracer Transport is concerned with using models to infer the ocean circulation. Understanding our climate is one of the major problems of the late twentieth century. The possible climatic changes resulting from the rise in atmospheric carbon dioxide and other trace gases are of primary interest and the ocean pla. ys a ma. jor role in determining the magnitude, temporal evolution and regional distribution of those changes. Because of the poor observational basis the ocean general circulation is not well understood. The World Ocean Circulation Experiment (WOCE) which is now underway is an attempt to improve our knowledge of ocean dynamics and thermodynamics on global scales relevant to climate change. Despite those efforts, the oceanic data base is likely to remain scarce and it is crucial to use appropriate methods in order to extract the maximum amount of information from observations. The book contains a thorough analysis of methods to combine data of val'ious types with dynamical concepts, and to assimilate data directly into ocean models. The properties of geocl;temical tracers such as HC, He, Tritium and Freons and how they may be used to impose integral constraints on the ocean circulation are discussed.

Download or read book IUTAM Symposium on Advances in Mathematical Modelling of Atmosphere and Ocean Dynamics written by P.F. Hodnett and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Ocean Mixing written by Michael Meredith and published by Elsevier. This book was released on 2021-09-16 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean Mixing: Drivers, Mechanisms and Impacts presents a broad panorama of one of the most rapidly-developing areas of marine science. It highlights the state-of-the-art concerning knowledge of the causes of ocean mixing, and a perspective on the implications for ocean circulation, climate, biogeochemistry and the marine ecosystem. This edited volume places a particular emphasis on elucidating the key future questions relating to ocean mixing, and emerging ideas and activities to address them, including innovative technology developments and advances in methodology. Ocean Mixing is a key reference for those entering the field, and for those seeking a comprehensive overview of how the key current issues are being addressed and what the priorities for future research are. Each chapter is written by established leaders in ocean mixing research; the volume is thus suitable for those seeking specific detailed information on sub-topics, as well as those seeking a broad synopsis of current understanding. It provides useful ammunition for those pursuing funding for specific future research campaigns, by being an authoritative source concerning key scientific goals in the short, medium and long term. Additionally, the chapters contain bespoke and informative graphics that can be used in teaching and science communication to convey the complex concepts and phenomena in easily accessible ways. - Presents a coherent overview of the state-of-the-art research concerning ocean mixing - Provides an in-depth discussion of how ocean mixing impacts all scales of the planetary system - Includes elucidation of the grand challenges in ocean mixing, and how they might be addressed

Download or read book Multiple zonal jets in a quasigeostrophic model of the Antarctic Circumpolar Current written by A.M. TREGUIER and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: