Download or read book Modeling Diffusion in the Antarctic Circumpolar Current written by Clifford Hill Hodges and published by . This book was released on 2004 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to understand the role of eddies in lateral mixing in a rotating fluid, a small scale laboratory model is constructed. An experiment is carried out in a rotating, differentially heated annulus and the evolution of a dye tracer mixed by turbulent motions is studied. Images are analyzed to extract the concentration mappings of tracer throughout the tank at each time instance and a diffusion coefficient K(r) is inferred.

Download or read book Contributions to the Dynamics of the Antarctic Circumpolar Current A C C II written by Takashi Ichiye and published by . This book was released on 1975 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-dimensional equations of motion are derived for the A.C.C. of the barotropic mode, including the bottom friction and the horizontal eddy viscosity. Integration of the vorticity equation leads to the zeroth order stream function which is dependent only on depth divided by Coriolis' parameter. Integration of the momentum equation along a streamline yields the relation between the momentum input by wind stress and its dissipation by the bottom friction and by the horizontal eddy viscosity. The relation determines the magnitude of the stream function. It also explains differences in the total transport of the A.C.C. obtained by Kamenkovich (1962) and by Bryan and Cox (1972).

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 Ocean Circulation and Climate written by B. Fox-Kemper and published by Elsevier Inc. Chapters. This book was released on 2013-10-22 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dominant processes leading to lateral transport by the general ocean circulation are reviewed. The general circulation is distinguished from a theoretical steady flow by the effects of mesoscale eddies. The general circulation flow may be averaged over the scale of the eddies, but averaging does not eliminate correlations among eddy variables. The present state of understanding of the transport by these eddy correlations, and how they are parameterized in models, is discussed in some detail. Satellite, drifter, and model estimates of eddy statistics are compared. Particular emphasis is placed on the direction, heterogeneity, and anisotropy of eddy-induced diffusion, advection, and transport.

Download or read book Numerical Modeling of the Global Atmosphere in the Climate System written by Philip Mote and published by Springer Science & Business Media. This book was released on 2000-04-30 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: 21. Simulating Future Climate G. J. Boer 1 Introduction. . . . . . . . . . . . . . . . 489 2 International Aspects . . . . . . . . . . . 490 3 Simulating Historical and Future Climate 492 4 Climate Change in the 20th Century . . . 495 5 Simulating Future Climate Change 498 6 Climate Impact, Adaptation, and Mitigation 501 7 Summary . 502 Index 505 PREFACE Numerical modeling ofthe global atmosphere has entered a new era. Whereas atmospheric modeling was once the domain ofa few research units at universities or government laboratories, it can now be performed almost anywhere thanks to the affordability of computing power. Atmospheric general circulation models (GCMs) are being used by a rapidly growing scientific community in a wide range of applications. With widespread interest in anthropogenic climate change, GCMs have a role also in informing policy discussions. Many of the scientists using GCMs have backgrounds in fields other than atmospheric sciences and may be unaware of how GCMs are constructed. Recognizing this explosion in the application of GCMs, we organized a two week course in order to give young scientists who are relatively new to the field of atmospheric modeling a thorough grounding in the basic principles on which GCMs are constructed, an insight into their strengths and weaknesses, and guid ance on how meaningful numerical experiments are formulated and analyzed. Sponsored by the North Atlantic Treaty Organization (NATO) and other institu tions, this Advanced Study Institute (ASI) took place May 25-June 5, 1998, at II Ciocco, a remote hotel on a Tuscan hillside in Italy.

Download or read book Numerical Models of Ocean Circulation written by and published by National Academies. This book was released on 1975 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deep Circulation in the Eastern South Pacific written by Vincent Faure and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The model uses a forward advection-diffusion model and Markov Chain Monte-Carlo techniques to give estimates of velocities along and across surfaces of neutral density as well as isopycnal diffusivities. It is composed of 9 layers between the 27.4 and 28 neutral densities. The circulation in the upper layers of the model compares well with direct independent estimates of velocities from subsurface float trajectories (WOCE and Argo). We investigate the water exchange in the deeper layers in regards to the 3He distribution along the Eastern boundary and its mixing with the Antarctic Circumpolar Current. The model is able to estimate vertically dependent rates of oxygen utilization as well as lateral eddy diffusivities of tracers.

Download or read book Modeling Methods for Marine Science written by David M. Glover and published by Cambridge University Press. This book was released on 2011-06-02 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced textbook on modeling, data analysis and numerical techniques for marine science has been developed from a course taught by the authors for many years at the Woods Hole Oceanographic Institute. The first part covers statistics: singular value decomposition, error propagation, least squares regression, principal component analysis, time series analysis and objective interpolation. The second part deals with modeling techniques: finite differences, stability analysis and optimization. The third part describes case studies of actual ocean models of ever increasing dimensionality and complexity, starting with zero-dimensional models and finishing with three-dimensional general circulation models. Throughout the book hands-on computational examples are introduced using the MATLAB programming language and the principles of scientific visualization are emphasised. Ideal as a textbook for advanced students of oceanography on courses in data analysis and numerical modeling, the book is also an invaluable resource for a broad range of scientists undertaking modeling in chemical, biological, geological and physical oceanography.

Download or read book Structure and Variability of the Antarctic Circumpolar Current written by Ėduard Iosifovich Sarukhani︠a︡n and published by . This book was released on 1985 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Data Models and Analysis written by Guoqi Han and published by Routledge. This book was released on 2019-07-09 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the ten most cited articles that have appeared in the journal Atmosphere-Ocean since 1995. These articles cover a wide range of topics in meteorology, climatology and oceanography. Modelling work is represented in five papers, covering global climate model development; a cumulus parameterization scheme for global climate models; development of a regional forecast modelling system and parameterization of peatland hydraulic processes for climate models. Data rehabilitation and compilation in order to support trend analysis work on comprehensive precipitation and temperature data sets is presented in four papers. Field studies are represented by a paper on the circumpolar lead system. While the modelling studies are global in their application and applicability, the data analysis and field study papers cover environments that are specifically, but not uniquely, Canadian. This book will be of interest to researchers, students and professionals in the various sub-fields of meteorology, oceanography and climate science.

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 Survey of Theoretical Models of the Antarctic Circumpolar Current written by and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Ocean Circulation and Climate written by Gerold Siedler and published by Academic Press. This book was released on 2001-04-11 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the views of leading scientists on the knowledge of the global ocean circulation following the completion of the observational phase of the World Ocean Circulation Experiment. WOCE's in situ physical and chemical measurements together with satellite altimetry have produced a data set which provides for development of ocean and coupled ocean-atmosphere circulation models used for understanding ocean and climate variability and projecting climate change. This book guides the reader through the analysis, interpretation, modelling and synthesis of this data.

Download or read book Vorticity dynamics of seasonal variations of the Antarctic Circumpolar Current from a modeling study written by J.M. KLINCK and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Simple Model of the Residual Circulation of the Antarctic Circumpolar Current written by Angela Cheryl MacKenzie and published by . This book was released on 2004 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: