qxd 12/16/05 10:54 AM Page i Atmospheric Science Second Edition P732951-Prelims.qxd 12/16/05 10:54 AM Page ii This is Volume 92 in the INTERNATIONAL GEOPHYSICS SERIES A series of monographs and textbooks Edited by RENATA DMOWSKA, DENNIS HARTMANN, and H. THOMAS ROSSBY A complete list of books in this series appears at the end of this volume.qxd 12/16/05 10:54 AM Page iii Atmospheric Science An Introductory Survey Second Edition John M. Hobbs University of Washington AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier P732951-Prelims.qxd 12/16/05 10:54 AM Page iv Acquisitions Editor: Jennifer Helé Project Manager: Jeff Freeland Marketing Manager: Linda Beattie Marketing Coordinator: Francine Ribeau Cover Art Direction: Cate Rickard Barr Text Design: Julio Esperas Composition: Integra Software Services Private Limited Cover Printer: Transcontinental Printing Interior Printer: Transcontinental Printing Academic Press is an imprint of Elsevier 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA 525 B Street, Suite 1900, San Diego, California 92101-4495, USA 84 Theobald’s Road, London WC1X 8RR, UK This book is printed on acid-free paper. Copyright © 2006, Elsevier Inc.
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone: (+44) 1865 843830, fax: (+44) 1865 853333, E-mail: permissions@elsevier. You may also complete your request on-line via the Elsevier homepage (http:///elsevier.com), by selecting “Support & Contact” then “Copyright and Permission” and then “Obtaining Permissions.” Cover Photo Credits: Noboru Nakamura’s drawing, bearing the Latin inscription “Here watch the powerful machine of nature, formed by the air and other elements”, was inspired by mankind’s long-standing fascination with weather and climate.
Some of the products of this machine are represented by the other images (left to right): annual mean sea surface temperature (courtesy of Todd Mitchell), a single cell thunderstorm cell over a tropical Pacific atoll (courtesy of Art Rangno), a supercell thunderstorm over Kansas (courtesy of Chris Kridler), and Antarctic sea ice (courtesy of Miles McPhee). Library of Congress Cataloging-in-Publication Data Wallace, John M. (John Michael), 1940– Atmospheric science : an introductory survey / John M. Atmospheric physics—Textbooks.
Atmospheric chemistry—Textbooks. Hobbs, Peter Victor, 1936–2005 II.5—dc22 2005034642 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN 13: 978-0-12-732951-2 ISBN 10: 0-12-732951-X For information on all Academic Press Publications visit our Web site at www.com Printed in Canada 06 07 08 09 10 8 7 6 5 4 3 2 1 Working together to grow libraries in developing countries www.qxd 12/16/05 10:54 AM Page v In Memory of Peter V. Hobbs (1936–2005) I am the daughter of Earth and Water, And the nursling of the Sky; I pass through the pores of the ocean and shores; I change, but I cannot die.
For after the rain when with never a stain The pavilion of Heaven is bare, And the winds and sunbeams with their convex gleams Build up the blue dome of air, I silently laugh at my own cenotaph, And out of the caverns of rain, Like a child from the womb, like a ghost from the tomb, I arise and unbuild it again. PERCY BYSSHE SHELLEY The Cloud v P732951-Prelims.qxd 12/16/05 10:54 AM Page vi P732951-Prelims.qxd 12/16/05 10:54 AM Page vii Contents Preface to the Second Edition xi 2.3 The Past Million Years 52 Preface to the First Edition xv 2.4 The Past 20,000 Years 54 2.6 Earth: The Habitable Planet 56 1 Introduction and Overview 1 Exercises 58 1.1 Scope of the Subject and Recent Highlights 1 3 Atmospheric Thermodynamics 63 1.2 Some Definitions and Terms of 3.1 Gas Laws 63 Reference 3 3.3 A Brief Survey of the Atmosphere 6 3.2 The Hydrostatic Equation 67 1.2 Scale Height and the Hypsometric 1.3 Chemical Composition 8 Equation 69 1.3 Thickness and Heights of Constant 1.5 Winds 12 Pressure Surfaces 71 1.4 Reduction of Pressure to Sea Level 72 1.3 The First Law of Thermodynamics 72 Exercises 22 3.2 Specific Heats 75 2 The Earth System 25 3.1 Components of the Earth System 25 3.1 Concept of an Air Parcel 77 2.2 The Dry Adiabatic Lapse Rate 77 2.3 The Terrestrial Biosphere 35 3.4 The Earth’s Crust and Mantle 37 3.5 Roles of Various Components 3.5 Water Vapor in Air 79 of the Earth System in Climate 38 3.2 The Hydrologic Cycle 38 3.3 The Carbon Cycle 41 3.3 Saturated Adiabatic and 2.1 Carbon in the Atmosphere 42 Pseudoadiabatic Processes 84 2.2 Carbon in the Biosphere 42 3.4 The Saturated Adiabatic Lapse Rate 84 2.3 Carbon in the Oceans 44 3.5 Equivalent Potential Temperature 2.4 Carbon in the Earth’s Crust 44 and Wet-Bulb Potential Temperature 85 2.4 Oxygen in the Earth System 45 3.1 Sources of Free Oxygen 46 3.7 Net Effects of Ascent Followed 2.5 A Brief History of Climate and the by Descent 86 Earth System 48 3.1 Formation and Evolution of the 3.1 Unsaturated Air 88 Earth System 48 3.2 The Past 100 Million Years 51 3.3 Conditional and Convective Instability 91 vii P732951-Prelims.qxd 12/16/05 10:54 AM Page viii viii Contents 3.7 The Second Law of Thermodynamics 5.4 Tropospheric Aerosols 169 and Entropy 93 5.1 The Carnot Cycle 93 5.3 The Clausius–Clapeyron Equation 97 5.4 Generalized Statement of the Second 5.5 Concentrations and Size Distributions 174 Law of Thermodynamics 100 5.6 Residence Times 176 Exercises 102 5.1 Some Sources of Pollutants 177 4 Radiative Transfer 113 5.1 The Spectrum of Radiation 113 5.3 Regional and Global Pollution 181 4.2 Quantitative Description of Radiation 114 5.6 Tropospheric Chemical Cycles 182 4.1 The Nitrogen Cycle 182 4.1 The Planck Function 117 5.2 The Sulfur Cycle 183 4.2 Wien’s Displacement Law 118 5.3 The Stefan–Boltzmann Law 119 5.1 Unperturbed Stratospheric Ozone 185 4.4 Radiative Properties of 5.2 Anthropogenic Perturbations to Nonblack Materials 120 Stratospheric Ozone: The Ozone Hole 190 4.3 Stratospheric Aerosols; Sulfur in the 4.6 The Greenhouse Effect 121 Stratosphere 196 4.4 Physics of Scattering and Absorption Exercises 198 and Emission 122 4.1 Scattering by Air Molecules and 6 Cloud Microphysics 209 Particles 123 6.1 Nucleation of Water Vapor Condensation 209 4.2 Absorption by Particles 126 6.3 Absorption and Emission by 6.2 Cloud Condensation Nuclei 214 Gas Molecules 127 6.2 Microstructures of Warm Clouds 215 4.5 Radiative Transfer in Planetary 6.3 Cloud Liquid Water Content and Atmospheres 130 Entrainment 218 4.4 Growth of Cloud Droplets in Warm Clouds 221 4.2 Reflection and Absorption by a Layer 6.1 Growth by Condensation 221 of the Atmosphere 133 6.2 Growth by Collection 224 4.3 Absorption and Emission of Infrared 6.3 Bridging the Gap between Droplet Radiation in Cloud-Free Air 134 Growth by Condensation and 4.4 Vertical Profiles of Radiative Collision–Coalescence 228 Heating Rate 138 6.5 Microphysics of Cold Clouds 232 4.5 Passive Remote Sensing by Satellites 139 6.1 Nucleation of Ice Particles; Ice Nuclei 232 4.6 Radiation Balance at the Top of the 6.2 Concentrations of Ice Particles in Atmosphere 144 Clouds; Ice Multiplication 236 Exercises 145 6.3 Growth of Ice Particles in Clouds 238 6.4 Formation of Precipitation in Cold 5 Atmospheric Chemistry 153 Clouds 243 5.1 Composition of Tropospheric Air 153 6.5 Classification of Solid Precipitation 245 5.2 Sources, Transport, and Sinks of Trace Gases 157 6.6 Artificial Modification of Clouds and 5.1 Modification of Warm Clouds 245 5.2 Modification of Cold Clouds 247 5.3 Some Important Tropospheric Trace Gases 162 6.1 The Hydroxyl Radical 162 6.2 Some Reactive Nitrogen Compounds 163 6.2 Lightning and Thunder 254 5.3 The Global Electrical Circuit 256 5.8 Cloud and Precipitation Chemistry 259 5.2 Transport of Particles and Gases 259 P732951-Prelims.qxd 12/16/05 10:54 AM Page ix Contents ix 6.3 Cold Air Damming 341 6.4 Dissolution of Gases in Cloud Droplets 260 8.4 Terrain-Induced Windstorms 342 6.5 Aqueous-Phase Chemical Reactions 261 8.5 Orographic Influences on 6.6 Precipitation Scavenging 261 Precipitation 343 6.7 Sources of Sulfate in Precipitation 262 8.8 Chemical Composition of Rain 262 8.9 Production of Aerosol by Clouds 262 8.2 Structure and Evolution of Exercises 263 Convective Storms 349 8.3 Damaging Winds Associated with 7 Atmospheric Dynamics 271 Convective Storms 356 7.1 Kinematics of the Large-Scale Horizontal 8.4 Mesoscale Convective Systems 363 Flow 271 8.1 Elementary Kinematic Properties 8.1 Structure, Thermodynamics, of the Flow 271 and Dynamics 366 7.2 Vorticity and Divergence 272 8.2 Genesis and Life Cycle 369 7.4 Streamlines versus Trajectories 275 Exercises 371 7.2 Dynamics of Horizontal Flow 276 7.1 Apparent Forces 276 9 The Atmospheric Boundary Layer 375 7.3 The Horizontal Equation of Motion 280 9.1 Eddies and Thermals 376 7.4 The Geostrophic Wind 281 9.2 Statistical Description of Turbulence 378 7.5 The Effect of Friction 281 9.3 Turbulence Kinetic Energy and 7.6 The Gradient Wind 282 Turbulence Intensity 379 7.7 The Thermal Wind 283 9.4 Turbulent Transport and Fluxes 381 7.8 Suppression of Vertical Motions 9.5 Turbulence Closure 382 by Planetary Rotation 286 9.6 Turbulence Scales and Similarity 7.9 A Conservation Law for Vorticity 286 Theory 383 7.2 The Surface Energy Balance 385 7.1 Pressure as a Vertical Coordinate 291 9.2 Surface Energy Balance over Land 386 7.3 The Bulk Aerodynamic Formulae 387 7.3 The Thermodynamic Energy Equation 291 9.4 The Global Surface Energy Balance 390 7.4 Inference of the Vertical Motion Field 293 9.5 Solution of the Primitive Equations 295 9.6 An Application of Primitive Equations 296 9.4 The Atmospheric General Circulation 297 9.1 The Kinetic Energy Cycle 298 9.4 Day-to-Day and Regional Variations 7.2 The Atmosphere as a Heat Engine 300 in Boundary-Layer Structure 395 7.5 Numerical Weather Prediction 300 9.5 Nonlocal Influence of Stratification Exercises 304 on Turbulence and Stability 396 9.4 Evolution 398 8 Weather Systems 313 9.2 Boundary-Layer Growth 399 8.3 Cloud-Topped Boundary Layer 8.2 Fronts and Surface Weather 318 over Land 401 8.4 The Marine Boundary Layer 401 8.5 In Search of the Perfect Storm 336 9.6 Top–Down Influences 337 9.7 Influence of Latent Heat Release 338 9.3 Forest Canopy Effects 410 8.1 Lee Cyclogenesis and Lee Troughing 340 9.2 Rossby Wave Propagation along 9.6 The Boundary Layer in Context 411 Sloping Terrain 340 Exercises 413 P732951-Prelims.qxd 12/16/05 10:54 AM Page x x Contents 10 Climate Dynamics 419 10.1 The Present-Day Climate 419 10.1 Annual Mean Conditions 419 10.1 The Buildup of Greenhouse Gases 451 10.2 Dependence on Time of Day 422 10.2 Is Human-Induced Greenhouse 10.3 Seasonal Dependence 423 Warming Already Evident? 455 10.3 Projections of Future 10.1 Internally Generated Climate Human-Induced Greenhouse Variability 429 Warming 457 10.2 Coupled Climate Variability 431 10.5 Climate Monitoring and Prediction 458 10.3 Externally Forced Climate Variability 439 Exercises 460 10.3 Climate Equilibria, Sensitivity, and Constants and Conversions for Feedbacks 443 Atmospheric Science 467 10.1 Transient versus Equilibrium Abbreviations Used in Captions 469 Response 446 Index 471 P732951-Prelims.qxd 12/16/05 10:54 AM Page xi Preface to the Second 2 Edition In the 30 years that have passed since we embarked Storms, the Global Energy Balance, and the General on the first edition of this book, atmospheric science Circulation have been dropped, but much of the has developed into a major field of study with far- material that was contained in them has been moved reaching scientific and societal implications. Topics to other chapters. The coverage of atmospheric such as climate and atmospheric chemistry, which dynamics, radiative transfer, atmospheric electricity, were not deemed sufficiently important to warrant convective storms, and tropical cyclones has been chapters of their own 30 years ago, are now major expanded.
The treatment of atmospheric thermody- branches of the discipline. More traditional topics namics has been modernized by using the skew such as weather forecasting, understanding the T ⫺ ln p chart as the primary format for plotting processes that lead to severe storms, and the radia- soundings.
