Meteorology Today: An Introduction to Weather, Climate, and the Environment

594 Pages·2012·137.79 MB·English

by  C. Donald Ahrens

C. Donald Ahrens
Peter L. Jackson
Christine E. J, Jackson
•
Meteorology Today
AN INTRODUCTION TO WEATHER, CLIMATE, AND THE ENVIRONMENT

Meteorology Today
AN INTRODUCTION TO WEATHER, CLIMATE, AND THE ENVIRONMENT
C. Donald Ahrens
Emeritus, Modesto Junior College
Peter L. jackson
University of Northern British Columbia
Christine E. j. jackson
University of Northern British Columbia
EDUCATION
~EDUCATION
Meteorology Today: An Introduction to Weather, Climate, and The Environment, First Canadian Edition
by C. Donald Ahrens, Peter L. Jackson, Christine E. J. Jackson
Vice President, Editorial Director: Production Service: Interior icons:
Evelyn Veitch MPS Limited, a Macmillan Company Focus on an Environmental Issue
(Iceberg): NOAA; Focus on an
Editor-in-Chief, Copy Editor:
Observation (Red sun setting
Higher Education: Holly Dickinson
and silhouettes): NOAA; Focus
Anne Williams
Proofreader: on a Special Topic (Sun on
Publisher: Dianne Fowlie horizon): Shutterstock; Focus on
Paul Fam an Advanced Topic (Antarctic
Indexer: sunset): NOAA
Executive Editor: Edwin Durbin
Jackie Wood Cover Design:
Manufacturing Manager-Higher Peter Papayanakis
Senior Marketing Manager: Education:
Sean Chamberland Joanne McNeil Cover Image:
Philip and Karen Smith/Getty
Developmental Editor: Design Director: Images
Suzanne Simpson Millar Ken Phipps
Compositor:
Photo and Permissions Researcher: Managing Designer: MPS Limited, a Macmillan Company
Melody Tolson Franca Amore
Printer:
Content Production Manager: Interior Design: Transcontinental
Christine Gilbert Cari Sherriff/Peter Papayanakis
COPYRIGHT © 2012 by Nelson ALL RIGHTS RESERVED. No part of Library and Archives Canada
Education Ltd. this work covered by the copyright Cataloguing in Publication
herein may be reproduced,
Adapted from Meteorology Today: Ahrens, C. Donald
transcribed, or used in any form or
An Introduction to Weather, Meteorology today : an
by any means-graphic, electronic,
Climate, and the Environment, introduction to weather, climate,
or mechanical, including
Ninth Edition by C. Donald Ahrens, and the environment I C. Donald
photocopying, recording, taping,
published by Brooks/Cole Cengage Ahrens, Peter L. Jackson, Christine
Web distribution, or information
Learning. Copyright ©2009 by E. J. Jackson.- 1st Canadian ed.
storage and retrieval systems
Brooks/Cole Cengage Learning.
without the written permission of Includes bibliographical references
Printed and bound in Canada the publisher. and index.
1 2 3 4 14 13 12 11 ISBN: 978-0-17-650039-9
For permission to use material
For more information contact from this text or product, submit 1. Meteorology- Textbooks.
Nelson Education Ltd., all requests online at 2. Meteorology-Canada
1120 Birchmount Road, Toronto, www.cengage.com/permissions. Textbooks. I. Jackson, Peter
Ontario, M1 K 5G4. Or you can visit Further questions about L. (Peter Lawrence), 1961-
our Internet site at permissions can be emailed to 11. Jackson, Christine E. J., 1961-
http://www.nelson.com [email protected] 111. Title.
Statistics Canada information is used Every effort has been made to QC861.3.A47 2011
with the permission of Statistics trace ownership of all copyrighted 551.5 C20 10-906419-4
Canada. Users are forbidden to copy material and to secure permission
this material and/or redisseminate from copyright holders. In the ISBN-13: 978-0-17-650039-9
the data, in an original or modified event of any question arising as ISBN-10: 0-17-650039-1
form, for commercial purposes, to the use of any material, we will
without the expressed permissions be pleased to make the necessary
of Statistics Canada. Information on corrections in future printings.
the availability of the wide range of
data from Statistics Canada can be
obtained from Statistics Canada's
Regional Offices, its World Wide
Web site at <http://www.statcan.ca>,
and its toll-free access number
1-800-263-1136.
IJ
MIX
Paper from
FSC responsible sources
www.fsc.org FSC® C011825
Earth and Its Atmosphere
CHAPTER I 3
Energy: Warming and Cooling' Earth and the Atmosphere
CHAPTER 2 33
Seasonal and Daily Temperatures
CHAPTER 3 65
Atmospheric Humidity
CHAPTER 4 99
Condensation: Dew, Fog, and Clouds
CHAPTER 5 125
Stability and Cloud Development
CHAPTER 6 165
Precipitation
CHAPTER 7 191
Air Pressure and Winds
CHAPTER 8 225
Winds at Different Scales-Small and Local
CHAPTER 9 257
Wind: Global Systems
CHAPTER 10 293
Air Masses and Fronts
CHAPTER I I 323
Middle-Latitude Cyclones
CHAPTER 12 351
Weather Forecasting
CHAPTER 13 381
Thunderstorms and Tornadoes
CHAPTER 14 415
Hurricanes
CHAPTER 15 457
Earth's Changing Climate
CHAPTER 16 487
Global Climate
CHAPTER 17 525
Air Pollution
CHAPTER 18 557
Light, Colour, and Atmospheric Optics
CHAPTER 19 593
NEL v

CHAPTER I
Heat Transfer in the Atmosphere 39
Earth and Its Atmosphere 3 Conduction 39
Convection 40
Earth as a System 4 Radiation 41
Overview of Earth's Atmosphere 4 Radiation and Temperature 41
Composition of the Atmosphere 5 Radiation of the Sun and Earth 42
FOCUS ON A SPECIAL TOPIC FOCUS ON AN ENVIRONMENTAL ISSUE
A Breath of Fresh Air 8 Wave Energy, Sun Burning. and Ultraviolet
The Early Atmosphere 11 Rays 44
Vertical Structure of the Atmosphere 12 Incoming Solar Energy 45
A Brief Look at Air Pressure and Air Density 12
FOCUS ON A SPECIAL TOPIC
FOCUS ON A SPECIAL TOPIC Characteristics of the Sun 46
The Atmospheres of Other Planets 14
Scattered and Reflected Light 47
Layers of the Atmosphere 15
FOCUS ON AN OBSERVATION
FOCUS ON AN OBSERVATION Blue Skies. Red Suns. and White Clouds 48
The Radiosonde 18
Radiation Absorption, Emission, and Equilibrium 49
The Ionosphere 18 Selective Absorbers and the Atmospheric
Weather and Climate 19 Greenhouse Effect 50
Meteorology: A Brief History 20 Enhancement of the Greenhouse Effect 51
A Satellite's View of the Weather 21 Annual and Daily Energy Balances 53
Storms ofA ll Sizes 21 Warming the Air from Below 53
A Look at a Weather Map 22 Earth's Annual Energy Balance 54
Weather and Climate in Our Lives 24
FOCUS ON A SPECIAL TOPIC
What Is a Meteorologist? 27
Summary 28
KeyTerms 28
Questions for Review 29
Questions for Thought 30
Problems and Exercises 30
CHAPTER 2
Energy: Warming and Cooling Earth
and the Atmosphere
33
Energy, Temperature, and Heat 34
Temperature Scales • 34
Forms of Energy 35
Specific Heat 36
Latent Heat-The Hidden Warmth 37
FOCUS ON A SPECIAL TOPIC
The Fate of a Sunbeam 38
IIEL vii
Daily Energy Balance at Earth's Surface 55 Protecting Crops from the Cold 81
The Geographic Controls of Temperature 83
FOCUS ON A SPECIAL TOPIC
Daily Radiation and Energy Budgets at Earth's Air Temperature Data 85
Daily, Monthly, and Yearly Temperatures 85
Surface 56
FOCUS ON A SPECIAL TOPIC
FOCUS ON A SPECIAL TOPIC
When It Comes to Temperature. What's
Solar Particles and the Aurora 58
Normal? 87
Summary 61
The Use of Temperature Data 87
Key Terms 61
Air Temperature and Human Comfort 88
Questions for Review 61
Questions for Thought 62 FOCUS ON AN OBSERVATION
A Thousand Degrees and Freezing to Death 91
Problems and Exercises 62
Measuring Air Temperature 91
CHAPTER 3 FOCUS ON AN OBSERVATION
Should Thermometers Be Read in the Shade7 94
Seasonal and Daily Temperatures 6s Summary 95
Key Terms 95
The Physical Controls of Temperature 66 Questions for Review 96
Why Earth Has Seasons 67 Questions for Thought 96
Seasons in the Northern Hemisphere 67 Problems and Exercises 97
FOCUS ON A SPECIAL TOPIC
Is December 21 Really the First Day of Winter7 72
CHAPTER 4
Seasons in the Southern Hemisphere 73
Local Seasonal Variations 74
Atmospheric Humidity
99
FOCUS ON AN ENVIRONMENTAL ISSUE
Solar Heating and the Noon Sun 75
Circulation of Water in the Atmosphere 100
Daily Temperature Variations 75 The Many Phases of Water 102
Daytime Warming 76 Evaporation, Condensation, and Saturation 102
Nighttime Cooling 77 Humidity 104
Radiation Inversions 77 Absolute Humidity 104
Specific Humidity and Mixing Ratio 105
FOCUS ON A SPECIAL TOPIC
Record High Temperatures 78 Vapour Pressure 105
FOCUS ON A SPECIAL TOPIC
FOCUS ON A SPECIAL TOPIC
Vapour Pressure and Boiling-The Higher You Go.
Record Low Temperatures 80
the Longer Cooking Takes I0 7
Relative Humidity 108
Relative Humidity and Dew Point 108
Comparing Humidities 112
FOCUS ON A SPECIAL TOPIC
Computing Relative Humidity and Dew Point 114
FOCUS ON A SPECIAL TOPIC
Is Humid Air "Heavier" than Dry Air? 115
Relative Humidity in the Home 115
Relative Humidity and Human Discomfort 116
FOCUS ON AN ADVANCED TOPIC
Psychrometry-Two Thermometers. a Wet
Sock. and 200 Years of Humidity Measurements 118
Measuring Humidity 119
Summary 121
Key Terms 121
Questions for Review 121
Questions for Thought 122
Problems and Exercises 122
viii NEL
CHAPTER 5 An Unstable Atmosphere 169
FOCUS ON A SPECIAL TOPIC
Condensation: Dew, Fog, Subsidence Inversions-Put a Lid on It 171
and Clouds A Conditionally Unstable Atmosphere 172
125
Causes of Instability 172
The Formation of Dew and Frost 126 Cloud Development 175
Condensation Nuclei 128 Convection and Clouds 176
Haze 129 Topography and Clouds 180
Fog 129
FOCUS ON AN OBSERVATION
Radiation Fog 130
Determining Convective Cloud Bases 181
FOCUS ON AN OBSERVATION Changing Cloud Forms 183
Why Are Canada's Coastal Regions so Foggy7 132
FOCUS ON AN ADVANCED TOPIC
Advection Fog 133
The Tephigram 184
FOCUS ON AN OBSERVATION Summary 187
Why Are Headlands Usually Foggier Than Key Terms 187
Beaches? 13 5 Questions for Review 187
Upslope Fog 136 Questions for Thought 188
Mixing Fog 136 Problems and Exercises 188
Evaporation Fog 136
Foggy Weather 137
CHAPTER 7
FOCUS ON A SPECIAL TOPIC
Fog That Forms by Mixing 138
Precipitation
191
FOCUS ON AN ENVIRONMENTAL ISSUE
Precipitation Processes 192
Fog Dispersal 140
How Do Cloud Droplets Grow Larger? 192
Clouds 141
Collision and Coalescence Process 194
Classification of Clouds 141
Cloud Identification 142
High Clouds 142
Middle Clouds 143
Low Clouds 144
Clouds with Vertical Development 146
Some Unusual Clouds 149
Cloud Observations 151
Determining Sky Conditions 151
FOCUS ON AN OBSERVATION
Measuring Cloud Ceilings I 53
Satellite Observations 153
FOCUS ON A SPECIAL TOPIC
Satellites Do More Than Observe Clouds I 58
Summary 160
Key Terms 160
Questions for Review 160
Questions for Thought 161
Problems and Exercises 161
CHAPTER 6
Stability and Cloud Development
165
Atmospheric Stability 166
Determining Stability 167
A Stable Atmosphere 167
NEL ix