Atmosfera, Tempo e Clima

Atmosfera, Tempo e Clima

(Parte 1 de 9)

Atmosphere, Weather and Climateis the essential introduction to weather processes and climatic conditions around the world, their observed variability and changes, and projected future trends. Extensively revised and updated, this eighth edition retains its popular tried and tested structure while incorporating recent advances in the field. From clear explanations of the basic physical and chemical principles of the atmosphere, to descriptions of regional climates and their changes, Atmosphere, Weather and Climate presents a comprehensive coverage of global meteorology and climatology. In this new edition, the latest scientific ideas are expressed in a clear, nonmathematical manner.

New features include:

new introductory chapter on the evolution and scope of meteorology and climatology new chapter on climatic models and climate system feedbacks updated analysis of atmospheric composition, weather and climate in middle latitudes, atmospheric and oceanic motion, tropical weather and climate, and small-scale climates chapter on climate variability and change has been completely updated to take account of the findings of the IPCC 2001 scientific assessment new more attractive and accessible text design new pedagogical features include: learning objectives at the beginning of each chapter and discussion points at their ending, and boxes on topical subjects and twentieth-century advances in the field.

Roger G. Barryis Professor of Geography, University of Colorado at Boulder, Director of the World Data Center for Glaciology and a Fellow of the Cooperative Institute for Research in Environmental Sciences.

The late Richard J. Chorleywas Professor of Geography at the University of Cambridge.

Atmosphere, Weather and Climate

Atmosphere, Weather and Climate

EIGHTH EDITION Roger G. Barry and Richard J. Chorley

First published 1968 by Methuen & Co. Ltd Second edition 1971 Third edition 1976 Fourth edition 1982 Fifth edition 1987 Reprinted by Routledge 1989, 1990 Sixth edition 1992 Reprinted 1995 Seventh edition 1998 by Routledge

Eighth edition 2003 by Routledge 1 New Fetter Lane, London EC4P 4EE

Simultaneously published in the USA and Canada by Routledge 29 West 35th Street, New York, NY 10001

Routledge is an imprint of the Taylor & Francis Group

© 1968, 1971, 1976, 1982, 1987, 1992, 1998, 2003 Roger G. Barry and Richard J. Chorley

All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers.

British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library

Library of Congress Cataloging in Publication Data Barry, Roger Graham.

Atmosphere, weather, and climate / Roger G. Barry & Richard J. Chorley. – 8th ed. p. cm.

Includes bibliographical references and index. 1. Meteorology. 2. Atmospheric physics. 3. Climatology. I.Chorley, Richard J.I.Title QC861.2.B36 2004 551.5–dc21 2003000832

ISBN 0–415–27170–3 (hbk) ISBN 0–415–27171–1 (pbk)

This edition published in the Taylor & Francis e-Library, 2004.

ISBN 0-203-42823-4 Master e-book ISBN ISBN 0-203-44051-X (Adobe eReader Format)

This edition is dedicated to my co-author Richard J. Chorley, with whom I first entered into collaboration on Atmosphere, Weather and Climatein 1966. He made numerous contributions, as always, to this eighth edition, notably Chapter 1 which he prepared as a new introduction. His many insights and ideas for the book and his enthusiasms over the years will be sadly missed.

Roger G. Barry March 2003

Preface to the eighth editionxi Acknowledgements xiii

1Introduction and history of meteorology and climatology1

AThe atmosphere1 BSolar energy2 C Global circulation 3 D Climatology 3 E Mid-latitude disturbances 4 FTropical weather5 G Palaeoclimates 6 HThe global climate system6

2Atmospheric composition, mass and structure 9

BMass of the atmosphere22 1Total pressure22 2Vapour pressure24

3Solar radiation and the global energy budget32

ASolar radiation32 1Solar output32 2Distance from the sun34 3Altitude of the sun36 4Length of day37

BSurface receipt of solar radiation and its effects 37 1Energy transfer within the earth–atmosphere system 37 2Effect of the atmosphere38 3Effect of cloud cover39 4Effect of latitude40 5Effect of land and sea41 6Effect of elevation and aspect48 7Variation of free-air temperature with height 48

CTerrestrial infra-red radiation and the greenhouse effect51

DHeat budget of the earth53 EAtmospheric energy and horizontal heat transport 57 1The horizontal transport of heat57 2Spatial pattern of the heat budget components 59

4Atmospheric moisture budget64

AThe global hydrological cycle64 B Humidity 6 vii


C Evaporation 69 D Condensation 73 EPrecipitation characteristics and measurement 74 1Forms of precipitation74 2 Precipitation characteristics 75 a Rainfall intensity 75 bAreal extent of a rainstorm76 cFrequency of rainstorms76 3The world pattern of precipitation79 4Regional variations in the altitudinal maximum of precipitation80 5 Drought 84

5Atmospheric instability, cloud formation and precipitation processes89

AAdiabatic temperature changes89 B Condensation level 91 CAir stability and instability91 DCloud formation95 1 Condensation nuclei 95 2Cloud types96 3Global cloud cover99

ALaws of horizontal motion112 1The pressure-gradient force113 2The earth’s rotational deflective (Coriolis) force 113 3The geostrophic wind114 4The centripetal acceleration114 5Frictional forces and the planetary boundary layer116

CLocal winds120 1Mountain and valley winds120 2Land and sea breezes121 3Winds due to topographic barriers122

7Planetary-scale motions in the atmosphere and ocean127

AVariation of pressure and wind velocity with height 127 1The vertical variation of pressure systems128 2Mean upper-air patterns129 3Upper wind conditions131 4Surface pressure conditions133

BThe global wind belts136 1The trade winds136 2The equatorial westerlies136 3The mid-latitude (Ferrel) westerlies139 4The polar easterlies139

CThe general circulation139 1Circulations in the vertical and horizontal planes 142 2Variations in the circulation of the northern hemisphere 146 aZonal index variations146 bNorth Atlantic Oscillation147

DOcean structure and circulation149 1Above the thermocline149 a Vertical 149 b Horizontal 151 2Deep ocean water interactions155 a Upwelling 155 bDeep ocean circulation155 3The oceans and atmospheric regulation158

8Numerical models of the general circulation, climate and weather prediction162 T.N. Chase and R.G. Barry


CData sources for forecasting168 DNumerical weather prediction170 1Short- and medium-range forecasting170 2 ‘Nowcasting’ 172 3 Long-range outlooks 172

9Mid-latitude synoptic and mesoscale systems 177

AThe airmass concept177 BNature of the source area177 1Cold airmasses178 2Warm airmasses180

C Airmass modification 181 1Mechanisms of modification181 a Thermodynamic changes 181 bDynamic changes182 2The results of modification: secondary airmasses 182 aCold air182 bWarm air182 3The age of the airmass183

FZones of wave development and frontogenesis 193

GSurface/upper-air relationships and the formation of frontal cyclones196

H Non-frontal depressions 199 1The lee cyclone199 2The thermal low199 3Polar air depressions201 4The cold low201

IMesoscale convective systems201

10Weather and climate in middle and high latitudes 213

A Europe 213 1Pressure and wind conditions213 2Oceanicity and continentality215

3British airflow patterns and their climatic characteristics 215 4Singularities and natural seasons220 5 Synoptic anomalies 221 6 Topographic effects 2

BNorth America225 1 Pressure systems 226 2The temperate west coast and Cordillera229 3Interior and eastern North America231 aContinental and oceanic influences231 bWarm and cold spells233 cPrecipitation and the moisture balance234

CThe subtropical margins238 1The semi-arid southwestern United

11Tropical weather and climate262

AThe intertropical convergence263 B Tropical disturbances 265 1 Wave disturbances 266 2 Cyclones 269 aHurricanes and typhoons269 bOther tropical disturbances274 3Tropical cloud clusters274

DEast Asian and Australian summer monsoons 289

ECentral and southern Africa292 1The African monsoon292 2Southern Africa297

F Amazonia 299 GEl Niño–Southern Oscillation (ENSO) events 302 1The Pacific Ocean302 2 Teleconnections 306

HOther sources of climatic variations in the tropics 309 1Cool ocean currents309 2 Topographic effects 309 3 Diurnal variations 311

IForecasting tropical weather312 1Short- and extended-range forecasts312 2 Long-range forecasts 313

12Boundary layer climates321

ASurface energy budgets322 BNon-vegetated natural surfaces323 1Rock and sand323 2 Water 324 3Snow and ice324

C Vegetated surfaces 325 1Short green crops325 2 Forests 327 aModification of energy transfers328 bModification of airflow329 cModification of the humidity environment 330 dModification of the thermal environment 332

DUrban surfaces333 1Modification of atmospheric composition333 a Aerosols 334 b Gases 337 cPollution distribution and impacts338 2Modification of the heat budget339 a Atmospheric composition 340 bUrban surfaces341 cHuman heat production341 dHeat islands341 3Modification of surface characteristics344 a Airflow 344 b Moisture 345 4Tropical urban climates346

A General considerations 353 BClimate forcings and feedbacks354 1 External forcing 356 2Short-term forcing and feedback358

CThe climatic record359 1The geological record359 2Late glacial and post-glacial conditions361 3The past 1000 years362

DPossible causes of recent climatic change368 1 Circulation changes 368 2Energy budgets368 3 Anthropogenic factors 370

EModel strategies for the prediction of climate change374

FThe IPCC models376 GOther environmental impacts of climate change 378 1 Sea-level 378 2Snow and ice382 3 Hydrology 384 4 Vegetation 384

1 Climate classification 391 AGeneric classifications related to plant growth or vegetation391

BEnergy and moisture budget classifications392 C Genetic classifications 395 DClassifications of climatic comfort396

2Système International (SI) units399 3Synoptic weather maps401

4Data sources404 ADaily weather maps and data404 BSatellite data404 CClimatic data404 DSelected sources of information on the World Wide Web405

Notes 406 Bibliography 409 Index 412

Black and white plates 1–19 are located between p. 8–9 and plates 20–29 between p. 1–12. Colour plates A–H are between p. 176–7.

When the first edition of this book appeared in 1968, it was greeted as being ‘remarkably up to date’ (Meteorological Magazine). Since that time, several new editions have extended and sharpened its description and analysis of atmospheric processes and global climates. Indeed, succeeding prefaces provide a virtual commentary on recent advances in meteorology and climatology of relevance to students in these fields and to scholars in related disciplines. This revised and expanded eighth edition of Atmosphere, Weather and Climatewill prove invaluable to all those studying the earth’s atmosphere and world climate, whether from environmental, atmospheric and earth sciences, geography, ecology, agriculture, hydrology or related disciplinary perspectives.

Atmosphere, Weather and Climateprovides a comprehensive introduction to weather processes and climatic conditions. Since the last edition in 1998, we have added an introductory overview of the historical development of the field and its major components. Following this there is an extended treatment of atmospheric composition and energy, stressing the heat budget of the earth and the causes of the greenhouse effect. Then we turn to the manifestations and circulation of atmospheric moisture, including atmospheric stability and precipitation patterns in space and time. A consideration of atmospheric and oceanic motion on small to large scales leads on to a new chapter on modelling of the atmospheric circulation and climate, that also presents weather forecasting on different time scales. This was prepared by my colleague Dr Tom Chase of CIRES and Geography at the University of Colorado, Boulder. This is followed by a discussion of the structure of air masses, the development of frontal and non-frontal cyclones and of mesoscale convective systems in mid-latitudes. The treatment of weather and climate in temperate latitudes begins with studies of Europe and America, extending to the conditions of their subtropical and high-latitude margins and includes the Mediterranean, Australasia, North Africa, the southern westerlies, and the sub-arctic and polar regions. Tropical weather and climate are also described through an analysis of the climatic mechanisms of monsoon Asia, Africa, Australia and Amazonia, together with the tropical margins of Africa and Australia and the effects of ocean movement and the El Niño–Southern Oscillation and teleconnections. Small-scale climates – including urban climates – are considered from the perspective of energy budgets. The final chapter stresses the structure and operation of the atmosphere–earth–ocean system and the causes of its climate changes. Since the previous edition appeared in 1998, the pace of research on the climate system and attention to global climate change has accelerated. A discussion of the various modelling strategies adopted for the prediction of climate change is undertaken, relating in particular to the IPCC 1990 to 2000 models. A consideration of other environmental impacts of climate change is also included.

The new information age and wide use of the World

Wide Web has led to significant changes in presentation. Apart from the two new chapters 1 and 8, new features include: learning points and discussion topics for each chapter, and boxes presenting a special topic or a summary of pivotal advances in twentieth-century meteorology and climatology. Throughout the book, some eighty new or redrawn figures, revised tables

Preface to the eighth edition and new plates are presented. Wherever possible, the criticisms and suggestions of colleagues and reviewers have been taken into account in preparing this latest edition.

This new edition benefited greatly from the ideas and work of my long-time friend and co-author Professor Richard J. Chorley, who sadly did not live to see its completion; he passed away on 12 May 2002. He had planned to play a diminishing role in the eighth edition following his retirement several years earlier, but nevertheless he remained active and fully involved through March 2002 and prepared much of the new Chapter 1. His knowledge, enthusiasm and inspiration will be sorely missed.

CIRES and Department of Geography, University of Colorado, Boulder xii

We are very much indebted to: Mr A. J. Dunn for his considerable contribution to the first edition; the late Professor F. Kenneth Hare of the University of Toronto, Ontario, for his thorough and authoritative criticism of the preliminary text and his valuable suggestions; Alan Johnson, formerly of Barton Peveril School, Eastleigh, Hampshire, for helpful comments on Chapters 2 to 6 ; and to Dr C. Desmond Walshaw, formerly of the Cavendish Laboratory, Cambridge, and R. H. A. Stewart of the Nautical College, Pangbourne, for offering valuable criticisms and suggestions for the original text. Gratitude is also expressed to the following persons for their helpful comments with respect to the fourth edition: Dr Brian Knapp of Leighton Park School, Reading; Dr L. F. Musk of the University of Manchester; Dr A. H. Perry of University College, Swansea; Dr R. Reynolds of the University of Reading; and Dr P. Smithson of the University of Sheffield. Dr C. Ramage, a former member of the University of Hawaii and of CIRES, University of Colorado, Boulder, made numerous helpful suggestions on the revision of Chapter 1 for the fifth edition. Dr Z. Toth and Dr D. Gilman of the National Meteorological Center, Washington, DC, kindly helped in the updating of Chapter 8D and Dr M. Tolbert of the University of Colorado assisted with the environmental chemistry in the seventh edition and Dr N. Cox of Durham University contributed significantly to the improvement of the seventh edition. The authors accept complete responsibility for any remaining textual errors.

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