Synoptic Eddies in the Ocean

443 Pages·1986·16.99 MB·English

by  V. M. Kamenkovich, M. N. Koshlyakov, A. S. Monin (auth.), A. S. Monin (eds.)

SYNOPTIC EDDIES IN THE OCEAN
ENVIRONMENTAL FLUID MECHANICS
Managing Editor:
G. T. CSANADY, Woods Hole Oceanographic Institution, Woods Hole,
Massachusetts
Editorial Board:
A. J. DAVENPORT, University of Western Ontario, London, Ontario
B. B. HICKS, Atmospheric Turbulence and Diffusion Laboratory, Oak Ridge,
Tennessee
G. R. HILST, Electric Power Research Institute, Palo Alto, California
R. E. MUNN, University of Toronto, Ontario
J. D. SMITH, University of Washington, Seattle, Washington
Synoptic Eddies
in the Ocean
Edited by
V. M. KAMENKOVICH,
M. N. KOSHLYAKOV,
and
A. S. MONIN
P.P. Shirshov Institute of Oceanology
Academy of Sciences of the U.S.S.R.
Translated by V.M. Volosov
With a Preface by the late E.S.W. Simpson
D. Reidel Publishing Company
A MEMBER OF THE KLUWER ACADEMIC PUBLISHERS GROUP 00
Dordrecht / Boston / Lancaster / Tokyo
Library or Congress Cataloging.in.Publication Data
Kamenkovich, V. M. (Vladimir Moiseevich)
Synoptic eddies in the ocean.
(Environmental fluid mechanics)
Translation of: Sinopticheskie vikhri v okeane.
Bibliography: p.
Includes index.
1. Ocean mixing. 2. Eddies. I. Koshillikov, M. N. (Mikhail Nikolaevich) II. Monin,
A. S. (Andrei Sergeevich), 1921- . III. Title. IV. Series.
GC299.K3613 1986 551.47'01 85-23249
ISBN·13: 978·94·010·8506·9 e·ISBN·13: 978·94·009·4502·9
DOl: 10.1007/ 978·94·009·4502·9
Published by D. Reidel Publishing Company
P.O. Box 17, 3300 AA Dordrecht, Holland
Sold and distributed in the U.S.A and Canada
by Kluwer Academic Publishers,
190 Old Derby Street, Hingham, MA 02043, U.S.A.
In all other countries, sold and distributed
by Kluwer Academic Publishers Group,
P.O. Box 322, 3300 AH Dordrecht, Holland
Originally published in 1982 in Russian by Gidrometeoizdat under the title
CHHOOHlqECKME BMXPM B OKEAHE
This edition is an expanded edition of the Russian original
All Rights Reserved
© 1986 by D. Reidel Publishing Company, Dordrecht, Holland
Softcover reprint of hardcover 1st edition 1986
No part of the material protected by this copyright notice may be reproduced or utilized
if! any form or by any means, electronic or mechanical, including photocopying,
recording or by any information storage and retrieval system,
without written permission from the copyright owner
Table of Contents
PREFACE BY THE PRESIDENT OF SCOR Vll
PREFACE BY THE AUTHORS TO THE ENGLISH EDITION IX
CHAPTER 1. STRATIFICATION AND CIRCULATION OF THE
OCEAN (by A. S. Monin)
1. Oceanic Processes with Different Temporal and Spatial Scales 1
2. Stratification of the Ocean 6
3. Large-scale Currents 22
4. Synoptic Processes 28
CHAPTER 2. THEORY OF ROSSBY WAVES
1. The Quasigeostrophic Approximation (by V. M. Kamenkovich) 34
2. Rossby Waves (by V. M. Kamenkovich) 53
3. Weak Turbulence on the f3-Plane (by G. M. Reznik) 73
4. Rossby Solitons (by A. L. Berestov, V. M. Kamenkovich, and
A. S. Monin) 108
CHAPTER 3. THEORY OF OCEAN EDDIES
1. Baroclinic Instability of Large-scale Currents (by V. M.
Kamenkovich) 131
2. Generation of Eddies by Bottom Relief (by V. M.
Kamenkovich) 150
3. Generation of Eddies by Direct Forcing by the Atmosphere (by
G. M. Reznik) 153
4. Eddy-resolving Numerical Models (by V. M. Kamenkovich) 171
5. Statistical Dynamics of Ocean Eddies (by A. S. Monin) 189
CHAPTER 4. EDDIES OF WESTERN BOUNDARY CURRENTS
(by M. N. Koshlyakov)
1. Gulf Stream Eddies 208
2. Eddies of the Kuroshio System 232
3. Eddies of Other Western Boundary Currents 250
v
vi Contents
CHAPTER 5. EDDIES IN THE OPEN OCEAN (by M. N.
Koshlyakov)
1. First Indications. 'Polygon-70' and MODE 265
2. POLYMODE 283
3. Eddies at Low Latitudes 318
4. Eddies at High Latitudes 339
5. Synoptic Eddies in the World Ocean 363
CHAPTER 6. APPLIED PROBLEMS
1. Synoptic Eddies and Formation of Weather and Climate (by Yu.
A. Shishkov) 377
2. Synoptic Variability of Hydrochemical and Hydrobiological
Characteristics (by A. M. Chernyakova) 384
3. Acoustic Applications (by V. M. Kurtepov) 398
Bibliography 415
Subject Index 430
Preface by the President of SCOR
Not long ago the activities of SCOR * Working Group 34 led to the publication of
the book Eddies in Marine Science edited by the Chairman, Professor A. R.
Robinson. It was intended to provide an overview of present knowledge on
mesoscale eddies of the ocean and their influence in other fields of marine science,
and to be of interest and value to a wide range of marine scientists. However, it was
recognized that the rapidly expanding knowledge of mesoscale eddies and the
development of the underpinning hydrodynamics would mean that a full and
complete account of this most important field could not be achieved in one book.
Accordingly, SCOR invited Professor A. S. Monin to head the preparation of a
new book, the first of its kind, devoted to the dynamics of eddies in the ocean. This
book is now presented to the reader.
The first comprehensive survey of several eddies in the ocean by direct measure-
ment was accomplished by the Soviet expedition POLYGON-70 in which six
months of continuous current measurements were made at a network of seventeen
moorings in the tropical North Atlantic. This experiment revealed the basic
parameters of free ocean eddies and indicated their characterization in terms of
Rossby wave dynamics with baroclinic instability of the large-scale current as an
eddy-generating mechanism. Further successful field studies culminated in the
international POLYMODE experiment during 1977-1978 in which year-long meas-
urements of currents have made it possible to interpret open-ocean synoptic eddies
as a complicated synthesis of Rossby waves and large-scale quasigeostrophic
turbulence, and have yielded particularly rich material for the verification and
improvement of the theoretical models of ocean eddies.
The first chapter of the present book is introductory in character and will be very
useful to physicists and mathematicians who may wish to familiarize themselves
with one of the most important problems of oceanography. The second and third
chapters successively present the theory of ocean eddies. A particularly detailed
description is given of the most contemporary results, including the theories of
baroclinic instability of large-scale currents and large-scale oceanic turbulence,
numerical models of eddies, and the theory of Rossby solitary waves. The fourth
and fifth chapters contain several results of actual studies of eddies which give an
especially vivid illustration of their physical properties. It has appeared more
convenient to consider separately eddies of the western boundary currents and
'SCOR: Scientific Committee on Oceanic Research.
vii
viii Preface by the President of SCOR
those of the open ocean. In the fifth chapter particular emphasis is laid upon the
results of the special regional experiments mentioned above. The experimental
material in the fourth and fifth chapters is considered both in its own right and in
the light of theoretical considerations. Finally, the sixth chapter is devoted to
practical applications of eddy science.
The international theoretical and experimental studies presented in this book are
devoted to one of the most important problems of contemporary oceanography.
These studies provide a good example of work requiring international coordi-
nation, which is a responsibility of the Scientific Committee on Oceanic Research.
It therefore gives me particular pleasure to accept the invitation from Professor
Monin to contribute this Preface.
President, SCOR
E. S. W. SIMPSON
Preface by the Authors to the English
Edition
The great interest shown by oceanographers and scientists of many other special-
ities in synoptic ocean eddies can primarily be accounted for by the simple but very
significant fact that among various oceanic phenomena it is mainly eddies that
determine the 'oceanic weather' - that is, the instantaneous distributions of current
velocities, temperature, salinity, speed of sound, and other oceanographic charac-
teristics. Eddies also seem to play an important part in the formation of the ocean
climate, i.e. the average distributions of oceanographic characteristics and their
long-period variability. The time scales of synoptic eddies range from weeks to
months; their horizontal scales vary from tens of kilometers to the low hundreds of
kilometers, and their vertical scales are of the order of a kilometer. The velocities
of translatory motion of synoptic eddies are of the order of several kilometers a
day, whereas the velocities of water motion in the eddies are much greater than
those of mean currents. Observation data demonstrate a great variety of types of
ocean eddies. They can be crudely classified as eddies (rings) of western boundary
currents which have been known for several decades, and eddies in the open ocean
discovered in the 1960-1970s.
The discovery of synoptic eddies in the open ocean was a great event in post-war
oceanography. As far back as the 1930s the existence of strong synoptic inhomo-
geneities in seas and oceans was anticipated by V. B. Shtokman. In 1935 he
conducted a series of long-term current measurements in the Caspian Sea which
were continued in the post-war period in the Black Sea (1956) and the North
Atlantic (1958). An important step was made by the British oceanographer J. C.
Swallow, who discovered strong nonstationary currents at great depths in regions
west of Portugal (1958) and near Bermuda (1959-1960). The existence of strong
synoptic disturbances was also confirmed by the results of processing the data of
current and temperature measurements performed by American oceanographers in
the Bermuda region in 1954-1969 and north of the Gulf Stream in 1965-1967.
The first specialized (two-month) experiment intended for studying the spatial
structure of synoptic inhomogeneities in the ocean was proposed by V. B. Shtok-
man and was carried out by the P. P. Shirshov Institute of Oceanology of the USSR
Academy of Sciences in 1967 in the Arabian Sea (,Polygon-6T). The results of
processing the hydrographic observation data by the dynamic method made it
possible to chart synoptic eddies. The second specialized experiment, which made a
decisive contribution to the study of the synoptic variability of the ocean, was the
Soviet six-month expedition 'Polygon-70' in the tropical zone of the North Atlantic.
ix
x Preface by the Authors to the English Edition
The data of direct current measurements in this expedition were, for the first time,
used to construct charts of synoptic currents which proved the existence of synoptic
eddies in the open ocean and revealed their basic properties. In 1973 American
scientists performed an analogous three-month experiment (MODE) in the Sar-
gasso Sea which confirmed the discovery made by Soviet oceanographers. Finally,
in 1977-1979 the grandiose Soviet-American experiment POLYMODE was per-
formed. It revealed some new interesting specific properties of the structure and
dynamics of ocean eddies.
At present the problem of synoptic eddies has a central role in oceanography
and, therefore, an acute need is felt for monographs presenting both the basic
experimental results and the modern theoretical concepts of generation and evol-
ution of synoptic eddies in the ocean. This book attempts to fulfill this need.
The material of the book is clear from the table of contents where the authors of
different chapters and sections are indicated. The sections were discussed by the
authors to give the reader a consistent presentation of the modern state of this
branch of knowledge based on a unified approach to the phenomena under study.
The final editing of the text in view of this objective was performed by A. S. Monin.
We are indebted to many of our colleagues, mainly in the P. P. Shirshov Institute
of Oceanology of the USSR Academy of Sciences, for valuable discussion and help
in the preparation of the manuscript. We are particularly grateful to A. L.
Berestov, V. M. Kurtepov, G. M. Reznik, A. M. Chernyakova, and Yu. A.
Shishkov for their participation in writing some sections of the book. In comparison
with the first 1982 Russian edition, the text of the book has been completely revised
and has grown almost twice its size in content owing to the inclusion of the latest
results obtained in recent years and also to a more detailed presentation of some of
the problems.
V. M. KAMENKOVICH
M. N. KOSHL YAKOV
A. S. MONIN