Download or read book Sensitivity of Climate to Diapycnal Diffusivity in the Ocean written by Fabio Dalan and published by . This book was released on 2004 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Thus larger diapycnal diffusion is compensated for by changes in isopycnal diffusion and GM advection. Little change is found for the advective flux because of compensation between downward and upward advection. We present sensitivity results for the hysteresis curve of the thermohaline circulation. The stability of the climate system to slow freshwater perturbations is reduced as a consequence of a smaller diapycnal diffusivity. This result confirms the findings of 2-dimensional climate models. However, contrary to the results of these studies, a common threshold for the shutdown of the thermohaline circulation is not found in our model. Part II: The sensitivity of the transient climate to the diapycnal diffusivity in the ocean is studied for a global warming scenario in which CO2 increases by 1% per year for 75 years. The thermohaline circulation slows down for about 100 years and recovers afterward, for any value of the diapycnal diffusivity. The rates of slowdown and of recovery, as well as the percentage recovery of the circulation at the end of 1000-year integrations, are variable but a direct relation with the diapycnal diffusivity cannot be found ...
Download or read book Sensitivity of Climate Change to Diapycnal Diffusivity in the Ocean written by Fabio Dalan and published by . This book was released on 2003 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The diapycnal diffusivity of the ocean is one of the least known parameters in cur- rent climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse methods and energy budget calculations suggests as much as a factor of 5 difference in the global mean value of the diapycnal diffusivity. Yet, the climate is extremely sensitive to the diapycnal diffusivity, as shown by studies using single-hemispheric ocean General Circulation Models (GCMs) and 2-dimensional coupled models. In this thesis we study the sensitivity of both the current climate and the climate change to the diapycnal diffusivity - using, for the first time, a coupled model with a 3-dimensional global ocean component and idealized geometry. Our results show that, at equilibrium, the strength of the thermohaline circulation in the North Atlantic scales with the 0.44 power of the diapycnal diffusivity, in contrast to the theoretical value of 2/3. On the other hand, the strength of the circulation in the South Pacific scales with the 0.63 power of the diapycnal diffusivity. The implication is that the amount of water upwelling from the deep ocean may be regulated by the diapycnal diffusion in the Indo-Pacific ocean. The vertical heat balance in the ocean is controlled by: in the downward direction, (i) advection and (ii) diapycnal diffusion; in the upward direction, (iii) isopycnal diffusion and (iv) bolus velocity (GM) advection. The size of the latter three fluxes increases with diapycnal diffusivity.
Download or read book Sensitivity of the Ocean s Climate to Diapycnal Diffusivity in an EMIC written by Fabio Dalan and published by . This book was released on 2005 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) Surface warming, induced by enhanced CO2 in the atmosphere, leads to a reduction of the isopycnal slope which translates into a reduction of the above fluxes. The amount of reduction is directly related to the magnitude of the isopycnal diffusive flux and GM advective flux at equilibrium. These latter fluxes depend on the thickness of the thermocline at equilibrium, hence on the diapycnal diffusion. Thus, the increase of deep-ocean heat uptake with diapycnal diffusivity is an indirect effect that the latter parameter has on the isopycnal diffusion and GM advection.
Download or read book Sensitivities of Deep ocean Heat Uptake and Heat Content to Surface Fluxes and Subgrid scale Parameters in an Ocean GCM with Idealized Geometry written by Boyin Huang and published by . This book was released on 2002 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensitivities of the net heat flux into the deep-ocean (Qnet) and of the deep-ocean heat content (DOC) below 700 m are studied using an ocean general circulation model and its adjoint. Both are found to have very similar sensitivities. The sensitivity to the surface freshwater flux (E-P-R) is positive in the Atlantic, but negative in the Pacific and Southern Ocean. A positive sensitivity to the downward net surface heat flux is found only in the North Atlantic north of 40ʻN and the Southern Ocean. The diapycnal diffusivity of temperature affects Qnet and DOC positively in a large area of the tropics and subtropics in both the Pacific and Atlantic Ocean. The isopycnal diffusivity contributes to Qnet and DOC mainly in the Southern Ocean. Detailed analysis indicates that the surface freshwater flux affects Qnet and DOC by changing vertical velocity, temperature stratification, and overturning circulation. The downward net surface heat flux appears to increase Qnet and DOC by strengthening vertical advection and isopycnal mixing. The contribution of isopycnal diffusivity to Qnet and DOC is largely associated with the vertical heat flux due to isopycnal mixing. Similarly, the diapycnal diffusivity of temperature modulates Qnet and DOC through the downward heat flux due to diapycnal diffusion. The uncertainties of Qnet and DOC are estimated based on the sensitivities and error bars of observed surface forcing and oceanic diffusivities. For DOC, they are about 0.7°K (1°K = 3 x 1024 J) for the isopycnal diffusivity, 0.4°K for the diapycnal diffusivity of temperature, 0.3°K for the surface freshwater flux, and 0.1°K for the net surface heat flux and zonal wind stress. Our results suggest that the heat uptake by ocean GCMs in climate experiments is sensitive to the isopycnal diffusivity as well to the diapycnal thermal diffusivity.
Download or read book Sensitivities of Deep ocean Heat Uptake and Heat Content in an OGM with Idealized Geometry written by Boyin Huang and published by . This book was released on 2003 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The uncertainties of Qnet and DOC are estimated based on the sensitivities and error bars of observed surface forcing and oceanic diffusivities. For DOC, they are about 0.7°K (1°K = 3 x 1024J) for the isopycnal diffusivity, 0.4°K for the diapycnal diffusivity of temperature, 0.3°K for the surface freshwater flux, and 0.1°K for the net surface heat flux and zonal wind stress. Our results suggest that the heat uptake by ocean GCMs in climate experiments is sensitive to the isopycnal diffusivity as well to the diapycnal thermal diffusivity.
Download or read book Ocean Circulation and Climate written by Jennifer MacKinnon and published by Elsevier Inc. Chapters. This book was released on 2013-10-22 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diapycnal mixing in the ocean interior is driven by a wide range of processes, each with distinct governing physics and unique global geography. Here we review the primary processes responsible for turbulent mixing in the ocean interior, with an emphasis on active work from the past decade. We conclude with a discussion of global patterns of mixing and their importance for regional and large-scale modeling accuracy.
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 Fundamentals of Ocean Climate Models written by Stephen Griffies and published by Princeton University Press. This book was released on 2018-06-05 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book sets forth the physical, mathematical, and numerical foundations of computer models used to understand and predict the global ocean climate system. Aimed at students and researchers of ocean and climate science who seek to understand the physical content of ocean model equations and numerical methods for their solution, it is largely general in formulation and employs modern mathematical techniques. It also highlights certain areas of cutting-edge research. Stephen Griffies presents material that spans a broad spectrum of issues critical for modern ocean climate models. Topics are organized into parts consisting of related chapters, with each part largely self-contained. Early chapters focus on the basic equations arising from classical mechanics and thermodynamics used to rationalize ocean fluid dynamics. These equations are then cast into a form appropriate for numerical models of finite grid resolution. Basic discretization methods are described for commonly used classes of ocean climate models. The book proceeds to focus on the parameterization of phenomena occurring at scales unresolved by the ocean model, which represents a large part of modern oceanographic research. The final part provides a tutorial on the tensor methods that are used throughout the book, in a general and elegant fashion, to formulate the equations.
Download or read book Ocean Processes in Climate Dynamics written by P.M. Malanotte-Rizzoli and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most crucial but still very poorly understood topics of oceanographic science is the role of ocean processes in contributing to the dynamics of climate and global change. This book presents a series of high level lectures on the major categories of ocean/atmosphere processes. Three of these major issues are the focus of the lectures: (1) air--sea interaction processes; (2) water mass formation, dispersion and mixing; (3) general circulation, with specific emphasis on the thermohaline component. Global examples in the world ocean are provided and discussed in the lectures. In parallel, the Mediterranean Sea is a laboratory basin in providing analogues of the above global processes relevant to climate dynamics. They include the Mediterranean thermohaline circulation with its own `conveyor belt'; intermediate and deep water mass formation and transformations, dispersion and mixing. No other book in the field provides a review of fundamental lectures on these processes, coupled with global examples and their Mediterranean analogues.
Download or read book Ocean Circulation and Climate written by and published by Academic Press. This book was released on 2013-10-22 with total page 893 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book represents all the knowledge we currently have on ocean circulation. It presents an up-to-date summary of the state of the science relating to the role of the oceans in the physical climate system. The book is structured to guide the reader through the wide range of world ocean circulation experiment (WOCE) science in a consistent way. Cross-references between contributors have been added, and the book has a comprehensive index and unified reference list. The book is simple to read, at the undergraduate level. It was written by the best scientists in the world who have collaborated to carry out years of experiments to better understand ocean circulation. - Presents in situ and remote observations with worldwide coverage - Provides theoretical understanding of processes within the ocean and at its boundaries to other Earth System components - Allows for simulating ocean and climate processes in the past, present and future using a hierarchy of physical-biogeochemical models
Download or read book Driving the Ocean s Overturning written by Véronique Bugnion and published by . This book was released on 2001 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Climate Change and Global Warming Research and Application 2013 Edition written by and published by ScholarlyEditions. This book was released on 2013-06-21 with total page 870 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Climate Change and Global Warming Research and Application: 2013 Edition is a ScholarlyEditions™ book that delivers timely, authoritative, and comprehensive information about Aerosol Forcing. The editors have built Advances in Climate Change and Global Warming Research and Application: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Aerosol Forcing in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Climate Change and Global Warming Research and Application: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
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 Ocean Circulation written by Andreas Schmittner and published by John Wiley & Sons. This book was released on 2013-05-02 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 173. The ocean's meridional overturning circulation (MOC) is a key factor in climate change. The Atlantic MOC, in particular, is believed to play an active role in the regional and global climate variability. It is associated with the recent debate on rapid climate change, the Atlantic Multi-Decadal Oscillation (AMO), global warming, and Atlantic hurricanes. This is the first book to deal with all aspects of the ocean's large-scale meridional overturning circulation, and is a coherent presentation, from a mechanistic point of view, of our current understanding of paleo, present-day, and future variability and change. It presents the current state of the science by bringing together the world's leading experts in physical, chemical, and biological oceanography, marine geology, geochemistry, paleoceanography, and climate modeling. A mix of overview and research papers makes this volume suitable not only for experts in the field, but also for students and anyone interested in climate change and the oceans.
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 Diapycnal Mixing in the Ocean written by Ali Mashayek and published by . This book was released on 2013 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diapycnal Advection by Double Diffusion and Turbulence in the Ocean written by Louis C. St. Laurent and published by . This book was released on 1999 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of double-diffusive mixing in the North Atlantic thermocline is considered. Mixing observations are analyzed in terms of the stability parameters for shear and double-diffusive convection, and a nondimensional ratio of dissipation rates. While the model for turbulence describes most dissipation occurring in high shear, dissipation in low shear is better described by the salt-finger model, and a method for estimating the salt-finger enhancement of the diapycnal haline diffusivity over the thermal diffusivity is proposed. These calculations suggest that salt-finger driven haline flux drives diapycnal downwelling in the upper thermocline. The role of turbulence occurring above rough bathymetry in the abyssal Brazil Basin is also considered. The mixing levels along sloping bathymetry exceed the levels observed on ridge crests and canyon floors. Additionally, mixing levels modulated in phase with the spring-neap tidal cycle. A model of the dissipation rate is derived and used to specify the turbulent mixing rate and constrain the diapycnal advection in an inverse model for the steady circulation. The inverse model solution reveals the presence of a secondary circulation with zonal character. These results suggest that mixing in abyssal canyons plays an important role in the mass budget of Antarctic Bottom Water.
