Climate and circulation of the tropics

475 Pages·1985·29.136 MB·English

by  Stefan Hastenrath (auth.)

CLIMATE AND CIRCULATION OF THE TROPICS
ATMOSPHERIC SCIENCES LIBRARY
Editorial Advisory Board
R. A. Anthes, National Center for Atmospheric Research (U.S.A.)
A. Berger, Universite Catholique Louvain (Belgium)
P. J. Crutzen, Max-Planck-Institut fiir Chemie (F_R.G.)
H.-W. Georgii, Universitat Frankfurt (F.R.G.)
P. V. Hobbs, University of Washington, Seattle (U.S.A.)
A. Hollingsworth, European Centre for Medium Range Weather Forecasts, Reading (England)
G. E. Hunt, University College London (England)
K. Y. Kondratyev, Laboratory of Remote Sensing, Leningrad (U.S.S.R.)
T. N. Krishnamurti, The Florida State University, Tallahassee (U.S.A.)
J. Latham, University of Manchester Institute of Science and Technology (England)
D. K. Lilly, National Center for Atmospheric Research (U.S.A.)
J. London, University of Colorado, Boulder (U.S.A.)
A. H. Dart, National Oceanic and Atmospheric Administration (U.S.A.)
I. Orlanski, National Oceanic and Atmospheric Administration (U.S.A.)
H. R. Pruppacher, Johannes Gutenberg Universitat, Mainz (F.R.G.)
N. J. Rosenberg, University of Nebraska, Lincoln (U.S.A.)
C. J. E. Schuurmans, Rijksuniversiteit Utrecht (The Netherlands)
H. Tennekes, Koninklijk Nederlands Meteorologisch Instituut, de Bilt (The Netherlands)
S. A. Twomey, The University of Arizona (U.S.A.)
T. M. L. Wigley, University of East Anglia (England)
J. C. Wijngaard, National Center for Atmospheric Research (U.S.A.)
V. E. Zuev, Institute for Atmospheric Optics, Tomsk (U.S.S.R.)
STEFAN HASTENRATH
University of Wisconsin, Madison
Climate
and circulation
of the tropics
D. Reidel Publishing Company
A MEMBER OF THE KLUWER ACADEMIC PUBLISHERS GROUP "
Dordrecht / Boston / Lancaster / Tokyo
Library of Congress Cataloging-in-Publication Data
Hastenrath, S.
Climate and circulation of the tropics.
(Atmospheric sciences library)
Bibliography: p.
Includes indexes.
1. Tropics - Climate. 2. Atmospheric circulation -
Tropics. I. Title. II. Series.
QC993.5.H37 1985 551.6913 85-19651
ISBN-13: 978-94-010-8878-7 e-ISBN-13: 978-94-009-5388-8
DOl: 10.1007/978-94-009-5388-8
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, MA02043, U.S.A.
In all other countries, sold and distributed
by Kluwer Academic Publishers Group,
P.O. Box 322, 3300 AH Dordrecht, Holland.
All Rights Reserved.
© 1985 by D. Reidel Publishing Company.
Softcover reprint of the hardcover lst edition 1985
No part of the material protected by this copyright notice may be reproduced or
utilized in 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.
to the memory of Hellmut Berg
PREFACE
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. My work
with the World Meteorological Organization included in 1973-74 an affiliation with the University
of Nairobi, Kenya. I have since maintained contact with both the University of Nairobi and the
Kenya Meteorological Department. Concerning South America, I followed invitations to the
Universidad de los Andes in Merida, Venezuela, in 1978 and 1981, to the Divisi6n de Glaciologia y
Seguridad de Lagunas of Electroperu in the Cordillera Blanca of Peru in 1978 and 1982, and to
~!:e Tnstituto Nacional de Pesquisas Espaciais in Sao Jose dos Campos, S.P., Brazil, variously since
1979. I acknowledge the stimulation received at numerous conferences and workshops in the
United States and overseas. Surely I also learned through osmosis from my academic colleagues
and students at the University of Wisconsin. The U.S. National Science Foundation supported
our work on tropical problems over the past seventeen years. All these experiences and contacts
shaped my perception of the tropics.
For permission to reproduce illustrations, I thank R. T. Barber, Robert W. Burpee, Karl W.
Butzer, Toby N. Carlson, Pao-Shin Chu, Lawrence Coy, Jean Dettwiller, Clive Dorman, John
Findlater, John Flenley, Neil L. Frank, T. Fujita, William M. Gray, John Griffiths, John Horel,
R. A. Houze, John Imbrie, A. P. Kershaw, T. N. Krishnamurti, Ernest C. Kung, Wilhelm Lauer,
Marcel Leroux, Edward Lorenz, Syukuro Manabe, Andrew Mcintyre, Robert L. Molinari, Walter
Munk, Gerhard Neumann, Reginald Newell, Chester W. Newton, Neville Nicholls, Albert Pallmann,
George Philander, Stephen Pond, Warren Prell, Colin S. Ramage, Eugene M. Rasmusson, Richard
Reed, Herbert Riehl, H. U. Roll, James C. Sadler, Jagadish Shukla, Joanne S. Simpson, Henry
Stommel, Alayne F. Street-Perrott, I. Subbaramayya, John C. Swallow, Paul Tchernia, Kevin
vii
viii PREFACE
Trenberth, Thomas Van der Hammen, E. M. Van Zinderen Bakker, George Veronis, John M.
Wallace, Ming-Chin Wu, Klaus Wyrtki; Academic Press, Akademie der Wissenschaften der DDR,
Akademie der Wissenschaften und der Literatur Mainz, American Association for the Advancement
of Science, American Geophysical Union, American Meteorological Society, American Scientist,
ASECNA, Balkema Publishers, Birkhiiuser Verlag, Blackwell Scientific Publications, British Me
teorological Office, Edward Arnold Publishers, Elsevier Publishing Company, Enslow Publishers,
Geological Society of America, Goddard Space Flight Center, Her Brittanic Majesty's Stationery
Office, India Meteorological Department, John Wiley Publishers, Koninklijk Nederlands Me
teorologisch Instituut, La Recherche, Macmillan Journals Limited, Marine Technology Society,
McGraw-Hill Publishing Company, Meteorological Society of Japan, MIT Press, New Zealand
Meteorological Service, Pergamon Press, Prentice-Hall, Quaternary Research Center of University
of Washington, Inc., Rockefeller Institute Press, Royal Meteorological SOciety, Springer Verlag
Wien, Tellus, University of California Press, University Press of Hawaii, World Meteorological
Organization.
As with my earlier books, Eva Singer typed the numerous generations of manuscript drafts
and updates. Without her patience and her superb mastery of the word processor, this book would
have remained a pile of illegible hand-scribbled sheets. Doug Stenz assisted me with the graphics
and Klaus Wolter with the indexes and the bibliography of Chapter 12.
Although, in writing this book, I consulted thousands of publications in seven languages from
all around the tropics and extending from the last century to the middle of 1985, I indubitably
omitted important references by subjective selection or mere oversight, and I apologize.
I was fortunate to have various colleagues read and comment on all or specific chapters of a
~raft manuscript. I feel grateful to Colin Ramage, University of Hawaii; Peter Lamb, Illinois State
Water Survey; Jay McCreary, Nova University; Hermann Flohn, University of Bonn; Dick Grove,
University of Cambridge; John Imbrie, Brown University; Vernon Kousky, Climate Analysis
Center of NOAA; Abraham Oort, Geophysical Fluid Dynamics Laboratory of NOAA; Dick Reed,
University of Washington. In the publication of this book, I appreciate the effective cooperation
with David Larner of D. Reidel Publishing Company. Finally, I am indebted to myoid teacher
Hellmut Berg, who inspired us, who 25 years ago encouraged me to take a job in the tropics, and
to whose memory this book is dedicated.
Madison, July 1985 STEF AN HASTENRATH
TABLE OF CONTENTS
PREFACE vii
LIST OF FIGURES xiii
LIST OF TABLES xxi
CHAPTER 1. INTRODUCTION 1
References 4
CHAPTER 2. DIURNAL FORCINGS AND LOCAL CIRCULATIONS 6
2.1. Insolation and Heat Budget Forcing 6
2.2. Atmospheric Tides 8
2.3. Circulations on the Local and Meso-Scale 10
2.4. Diurnal Marches of Sea-Air Exchange, Cloudiness, and Precipitation 18
2.5. Synthesis 22
References 22
CHAPTER 3 ...P LANET ARY SCALE ATMOSPHERIC CIRCULATION 25
3.1. Mean Meridional Distribution of Temperature and Humidity 25
3.2. Zonal Wind Regime 28
3.3. Mean Meridional Circulation 30
3.4. Maintenance of the Global Circulation: Angular Momentum 30
3.5. Maintenance of the Global Circulation: Kinetic Energy 33
3.6. Synthesis 35
References 36
'::::!!A PTER 4. OCEAN CIRCULATION 37
4.1. Wind Stress and Motion Field in the Upper Ocean 37
4.2. The Subtropical Gyres 41
4.3. Equatorial Current Systems 46
4.3.1. Overview of Surface Circulation 46
4.3.2. Balance of Forces 49
4.3.3. The North Equatorial Countercurrent 50
4.3.4. Wind Stress, Vertical Motion, Thermocline and Surface Topography 52
4.3.5. The Equatorial Undercurrent 53
4.3.6. Equatorial Waves and Remote Forcing 55
4.3.7. Recent Discoveries of Subsurface Currents 55
4.4. The Monsoon Ocean 56
4.5. Deep Circulation 65
4.6. Synthesis 67
References 68
ix
x T ABLE OF CONTENTS
CHAPTER 5. HEAT AND WATER BUDGETS 72
5.1. Basic Theory 72
5.2. Net Radiation at the Top of the Atmosphere 75
5.3. Oceanic Heat Budget 82
5.4. Atmospheric Heat Budget 89
5.5. Water Budget 92
5.6. Relative Roles of Oceanic Versus Atmospheric Heat Transports 97
5.7. Synthesis 101
References 103
CHAPTER 6. REGIONAL CIRCULATION SYSTEMS 107
6.1. Overview of the Global Tropics 107
6.2. Jet Streams 115
6.2.1. Basic Dynamics 115
6.2.2. Subtropical Westerly Jet 116
6.2.3. Tropical Easterly Jet 120
6.2.4. West African Mid-Tropospheric Jet 122
6.2.5. East African Low Level Jet 123
6.3. Subtropical Highs 128
6.4. Trades 130
6.5. Trade Inversion 136
6.5.1. Spatial Patterns 137
6.5.2. Origin and Maintenance 147
6.5.3. Climatic Implications 148
6.6. Mid-Tropospheric Inversions 150
6.7. Equatorial Trough Zone 150
6.7.1. The Large-Scale Setting 150
6.7.2. Structure of the Intertropical Convergence Zone 151
6.7.2.1. Atlantic and Pacific Oceans 151
6.7.2.2. Indian Ocean 160
6.7.2.3. Africa 160
6.7.2.4. On Atmospheric and Oceanic Controls 164
6.7.3. Dynamics of Cross-Equatorial Flow 167
6.7.4. Equatorial Dry Zone 172
6.8. Monsoons 173
6.8.1. Defmition "and Global Perspective 173
6.8.2. Africa 175
6.8.3. Indian Ocean Sector 177
6.8.4. On the Heat and Moisture Budget of the Indian Monsoons 184
6.8.5. Numerical Modelling of the Indian Summer Monsoon 188
6.9. Zonal Circulations 189
6.10. Upper-Tropospheric Anticyclones 193
6.11. Wind Regimes of the Equatorial Stratosphere 195
6.12. Synthesis 195
References 199
TABLE OF CONTENTS xi
CHAPTER 7. CLIMATOLOGY OF WEATHER SYSTEMS 210
7.1. Clouds and Convection 211
7.2. Tropical Storms 211
7.3. Waves in the Easterlies 222
7.4. Squall Lines 230
7.5. Dust Storms of the Sudan 233
7.6. Monsoon Depressions 233
7.7. Subtropical Cyclones 234
7.8. Temporales of Pacific Central America 238
7.9. Cold Surges 240
7.10. Interannual Variability 242
7.11. Synthe sis 246
References 248
CHAPTER 8. INTERANNUAL VARIABILITY OF THE ATMOSPHERE-OCEAN
253
SYSTEM
253
8.1. Surface Patterns of the Southern Oscillation
8.2. EI Nifio 259
268
8.3. Rainfall Anomalies in Indonesia
8.4. Upper-Air Patterns of ENSO 274
8.5. Vagaries of the Indian Monsoon 283
293
8.6. The Secas of Northeast Brazil
300
8.7. Rainfall Variations in the Central American - Caribbean Region
303
8.8. Drought and Flood Regimes in Subsaharan Africa
310
8.9. Climate Anomalies at the Angola Coast
8.10. Hydrometeorological Anomalies in the ZaIre (Congo) Basin 313
314
8.11. Time Scales of Climate Variability
8.12. Synthesis 315
References 318
CHAPTER 9. CLIMA TE PREDICTION 330
01. Indian Monsoon 330
9.2. Indonesia Rainfall 336
9.3. EI Nifio 338
9.4. The Droughts of Northeast Brazil 339
9.5. Subsaharan Drought 345
9.6. Southern Africa 345
9.7. Kenya Rainfall 345
9.8. North Atlantic Hurricanes 346
9.9. Hong Kong Climate 346
9.10. Synthesis and Outlook 347
References 348