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Author: Sophie Wacongne
Publisher:
ISBN:
Category : Ocean circulation
Languages : en
Pages : 884
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Book Description
This study focuses on the zonal weakening, eastern termination and seasonal variations of the Atlantic equatorial undercurrent (EUC). The main and most original contribution of the dissertation is a detailed analysis of the Atlantic EUC simulated by Philander and Pacanowski's (1986)general circulation model (GCM), which provides a novel description of the dynamical regimes governing various regions of a nonlinear stratified undercurrent. Only in a narrow deep western region of the simulation does one find an approximately inertial regime corresponding to zonal acceleration. Elsewhere frictional processes cannot be ignored. The bulk of the mid-basin model EUC terminates in the overlying westward surface flow while only a small fraction (the deeper more inertial layers) terminates at the eastern coast. In agreement with observations, a robust feature of the GCM not present in simpler models is the apparent migration of the EUC core from above the thermocline in the west to below it in the east. In the GCM, this happens because the eastward flow is eroded more efficiently by vertical friction above the base of the thermocline than by lateral friction at greater depths. This mechanism is a plausible one for the observed EUC. A scale analysis using a depth scale which decreases with distance eastwards predicts the model zonal transition between western inertial and eastern inertio-frictional regimes. Historical and recent observations and simple models of the equatorial and coastal eastern undercurrents are reviewed, and a new analysis of current measurements in the eastern equatorial Atlantic is presented. Although the measurements are inadequate for definitive conclusions, they suggest that Lukas' (1981) claim of a spring surge of the Pacific EUC to the eastern coast and a seasonal branching of the EUC into a coastal southeastward undercurrent may also hold for the Atlantic Ocean. To improve the agreement between observed and modelled strength of the eastern undercurrent, it is suggested that the eddy coefficient of horizontal mixing should be reduced in future GCM simulations.
Author: Sophie Wacongne
Publisher:
ISBN:
Category : Ocean circulation
Languages : en
Pages : 884
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Book Description
This study focuses on the zonal weakening, eastern termination and seasonal variations of the Atlantic equatorial undercurrent (EUC). The main and most original contribution of the dissertation is a detailed analysis of the Atlantic EUC simulated by Philander and Pacanowski's (1986)general circulation model (GCM), which provides a novel description of the dynamical regimes governing various regions of a nonlinear stratified undercurrent. Only in a narrow deep western region of the simulation does one find an approximately inertial regime corresponding to zonal acceleration. Elsewhere frictional processes cannot be ignored. The bulk of the mid-basin model EUC terminates in the overlying westward surface flow while only a small fraction (the deeper more inertial layers) terminates at the eastern coast. In agreement with observations, a robust feature of the GCM not present in simpler models is the apparent migration of the EUC core from above the thermocline in the west to below it in the east. In the GCM, this happens because the eastward flow is eroded more efficiently by vertical friction above the base of the thermocline than by lateral friction at greater depths. This mechanism is a plausible one for the observed EUC. A scale analysis using a depth scale which decreases with distance eastwards predicts the model zonal transition between western inertial and eastern inertio-frictional regimes. Historical and recent observations and simple models of the equatorial and coastal eastern undercurrents are reviewed, and a new analysis of current measurements in the eastern equatorial Atlantic is presented. Although the measurements are inadequate for definitive conclusions, they suggest that Lukas' (1981) claim of a spring surge of the Pacific EUC to the eastern coast and a seasonal branching of the EUC into a coastal southeastward undercurrent may also hold for the Atlantic Ocean. To improve the agreement between observed and modelled strength of the eastern undercurrent, it is suggested that the eddy coefficient of horizontal mixing should be reduced in future GCM simulations.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 320
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Book Description
Author: Advisory Committee on Technology and Society
Publisher: National Academies Press
ISBN: 9780309037860
Category : Social Science
Languages : en
Pages : 1298
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Book Description
Cities and Their Vital Systems asks basic questions about the longevity, utility, and nature of urban infrastructures; analyzes how they grow, interact, and change; and asks how, when, and at what cost they should be replaced. Among the topics discussed are problems arising from increasing air travel and airport congestion; the adequacy of water supplies and waste treatment; the impact of new technologies on construction; urban real estate values; and the field of "telematics," the combination of computers and telecommunications that makes money machines and national newspapers possible.
Author:
Publisher:
ISBN:
Category : Marine meteorology
Languages : en
Pages : 680
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Book Description
Author:
Publisher:
ISBN:
Category : Meteorology
Languages : en
Pages : 1010
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Book Description
Author: Julian P. McCreary
Publisher: Springer Nature
ISBN: 9811958645
Category : Science
Languages : en
Pages : 523
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Book Description
The book is the first to focus on the physical oceanography of the North Indian Ocean (NIO), a special region of the global ocean that exhibits a distinct seasonality due to the impact of the South Asian Monsoon (SAM). It is written as a textbook about the NIO for graduate students, lecturers, and researchers in physical oceanography. It will also be useful for courses on the interior, coastal, and equatorial dynamics in any other ocean. It helps readers, particularly new entrants to the field, to gain a comprehensive understanding of tropical-ocean dynamics by: developing from first principles the equation set for the linear continuously stratified (LCS) model, which has long been used to study tropical oceans; and then obtaining solutions that explore different aspects of the dynamics. Part 1 of the book provides an overview of observed ocean circulations and forcing functions in the NIO that are linked to the SAM. Part 2 develops the equations of motion for the LCS model. Part 3 (Free Waves) and Part 4 (Forced Solutions) derive and discuss analytic solutions to the LCS model that illustrate basic processes in the interior (unbounded), coastal, and equatorial regions of the ocean. The last two chapters of Part 4 consider more complicated processes and phenomena that build upon the simpler solutions previously found: vertical propagation of coastal and equatorial waves, and the Indian Ocean's shallow overturning circulations. Each analytic solution is illustrated (and extended) by a suite of numerical LCS solutions presented as video clips, providing a powerful means for visualizing complex processes.
Author: Kenneth H. Brink
Publisher: Harvard University Press
ISBN: 9780674017412
Category : Political Science
Languages : en
Pages : 1096
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Book Description
Author: Lynne D. Talley
Publisher:
ISBN:
Category : North Pacific Ocean
Languages : en
Pages : 680
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Book Description
Author: S. Hastenrath
Publisher: Springer Science & Business Media
ISBN: 9401131562
Category : Science
Languages : en
Pages : 507
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Book Description
The first edition of my book "Climate and Circulation of the Tropics" was reasonably up to date to the middle of 1985. In a second printing in 1988 it was possible to complete a few literature references and to correct some misprints. However, vigorous research has taken place over the past five years in various areas of tropical climate dynamics, especially in the atmosphere-ocean mechanisms of climate anomalies, climate prediction, ocean circulation, and paleoclimates. Promising progress has also been made in the application of general circulation modelling to tropical climate problems. In the present second edition, named "Climate Dynamics of the Tropics", I have attempted to incorporate much of the recent work to late 1990. Chapters 8 and 9 have been essentially re-written, and major additions have been made to Chapters 4 and 12 in particular. I would like to acknowledge the continued support by the U.S. National Science Foundation over the past five years. B. Parthasarathy, Poona, and H. Lessmann, San Salvador, sent me updates of data series not easily accessible. I have benefitted from discussions with numerous colleagues in the United States and overseas. In the preparation of this second edition, Marilyn Wolff patiently transferred my illegible hand-written drafts onto word processor. Dierk Polzin and Dan Skemp assisted me with the creation of the page masters and the subject index and Christopher Collimore with the author index.
Author: S. Hastenrath
Publisher: Springer Science & Business Media
ISBN: 9400953887
Category : Science
Languages : en
Pages : 531
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Book Description
Tropical atmosphere and ocean are receiving increased attention in relation to the functioning of the global climate system, the remarkable climatic variability in low latitudes, and the associated manifold environmental and societal consequences. Beyond the traditional emphasis of meteor ology on weather analysis and forecasting, there is a growing interest in the climate and large scale circulation of the tropics. This book may serve as a text for graduate and upper-division undergraduate students in meteorology, and is also intended as a reference work for practicing meteorologists, and researchers in the atmospheric, oceanic, and other environmental sciences. I began writing this book in 1979, but the roots reach further back. Early experiences in North Africa fuelled my curiosity about the low latitudes. In 1960 I seized the opportunity to work in the National Meteorological Service of El Salvador in Central America. My interest in the tropics continued after joining the University of Wisconsin in 1963. Field research brought me to the equatorial Pacific, and many times to the tropical Americas and Africa. This involved visits and correspondence with many weather services. My acquaintance with Australasia and South Asia is limited to short study visits, but includes continuous contacts with colleagues at key research institutions in India, namely the India Meteorological Department, the Indian Institute of Tropical Meteorology, and Andhra University. A guest semester at the University of the Witwatersrand in 1971 and related travels provided a perspective on the problems of Southern Africa.
