130 Pages
English

Understanding Weather and the Environment

-

Gain access to the library to view online
Learn more

Description

For all curious readers, the Knowledge Guides open the door to a world of complex and captivating phenomena.
Accurate, detailed visual information is all defined in lay language to make it readily accessible to the non-expert. Definitions to scientific terms are given either in the explanation itself, or in the comprehensive glossary.

Subjects

Informations

Published by
Published 09 August 2012
Reads 0
EAN13 9782764408933
Language English
Document size 53 MB

Legal information: rental price per page 0.0027€. This information is given for information only in accordance with current legislation.

Exrait

THE VISUAL GUIDES

Understanding
Weather
and The Environment

QA INTERNATIONAL

Understanding
Climate
and the
Environment

Publisher
Editorial Director
Executive Editor
Illustrations Editor
Art Director
Graphic Designer
Writers

Computer Graphic Artists

Researchers

Translation
Copy Editor
Production
Prepress

Jacques Fortin

François Fortin

Serge D’Amico

Marc Lalumière

Rielle Lévesque

Anne Tremblay
Stéphane Batigne
Josée Bourbonnière
Nathalie Fredette
Agence Science-Presse
Jean-Yves Ahern
Maxime Bigras
Patrice Blais
Yan Bohler
Mélanie Boivin
Charles Campeau
Jocelyn Gardner
Jonathan Jacques
Alain Lemire
Raymond Martin
Nicolas Oroc
Carl Pelletier
Simon Pelletier
Frédérick Simard
Mamadou Togola
Yan Tremblay
Anne-Marie Brault
Jessie Daigle
Anne-Marie Villeneuve
Kathleen Wynd
Käthe Roth
Jane Broderick
Mac Thien Nguyen Hoang
Kien Tang
Karine Lévesque

Page Layout

Reviewers

Véronique Boisvert
Lucie Mc Brearty
Geneviève Théroux Béliveau

Gilles Brien
Yves Comeau
Frédéric Fabry
David B. Frost
Mario Laquerre
Marc Olivier
Judith Patterson

The visual guide to Understanding Climate and the Environment
was created and produced by
QA International
e
329, rue de la Commune Ouest, 3étage
Montréal (Québec) H2Y 2E1 Canada
T514.499.3000 F514.499.3010
©2007 QA International. All rights reserved.
No part of this book may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying and recording, or by any
information storage and retrieval system, without written permission from the
Publisher.

)3".




0RINTEDANDBOUNDIN3LOVAKIA
10 9 8 7 6 5 4 3 2 1 0 0180 97 006
www.qa-international.com

Understanding
Climate
and the
Environment

QA INTERNATIONAL

4

6 | Earth’s atmosphere
8The atmosphere
10Atmospheric pressure
12The movement of air masses
14 Winds
16Prevailing winds
18Local winds
20 Tornadoes
22The power of tornadoes

46
44
42
40
38
37
36
34
32
30
28
26

Life and death of a cyclone

Inside a cyclone

The birth of a cyclone
Lightning and thunder
Thunderstorms
Rainbows
Dew and fog
Types of precipitation
Precipitation
Identifying clouds
Clouds
Humidity

24 | Precipitation

Ta b l e

48 | Meteorology

50
52
54
56
58
60
62

Measurement instruments

Measuring the temperature

Balloons and radar

Geostationary satellites

Polar-orbiting satellites

Weather maps

Reading a weather map

o f

80The consequences of
El Niño and La Niña
78El Niño and La Niña
76Temperate climates
74Polar climates
72Tropical climates
70Desert climates
68Climates of the world
66The seasonal cycle
64 | Earth’s climates

c

o

n

82 | The environment
84The biosphere
86 Ecosystems
88 Soil
90 The water cycle
92The carbon and oxygen cycles
94The phosphorus and nitrogen cycles
96The greenhouse effect
98Global warming
100The ozone layer

t

102
104
106
108
110
112
114
116
118
119
120
122

e

Sources of air pollution
The effects of air pollution
Acid rain
Sources of water pollution
Water pollution
Treatment of wastewater
Soil pollution

Desertification
Nuclear waste
Pollution of the food chains
Selective sorting of waste
Recycling

n

t

s

124 | Glossary
126 | Index
128 |Photo credits

5

a thin gaseous layer that
The air that we breathe comes from the atmosphere,
surrounds Earth
and protects it somewhat from solar radiation. Like all other matter, air has weight,
but this weight varies greatly depending on altitude and temperature. Variations in pressure cause atmospheric

movements and air masses to collide with or slide by each other. Winds, light or strong, constant or unpredictable,

contribute to the

planet’s thermal equilibrium.

Earth’s atmosphere

8

10

12

14

16

18

20

22

The atmosphere
A thin protective layer

Atmospheric pressure
The weight of air

The movement of air masses
Fronts and depressions

Winds
Atmospheric circulation

Prevailing winds
Major atmospheric movements

Local winds
The result of relief features

Tornadoes
The most violent winds on Earth

The power of tornadoes
Killer whirlwinds

T h e a t m o s p h e r e

A thin protective layer

The atmosphere, defined as the gaseous envelope surrounding Earth, does not
have well-defined edges. Half of its air molecules are concentrated in a very thin
layer, 5 km thick, but there are still traces of air at more than 1,000 km altitude.
Because of their protective function, the different layers of the atmosphere
play an essential role in the existence of life on Earth. All of the major
Earth’s amtemteosoprohleoremone alaoso ccrugical phen.ere thn ihespmoat

THE COMPOSITION OF AIR

The composition of the atmosphere remains stable at all altitudes: nitrogen and oxygen
represent 99% of its volume. Other gases, including argon and neon, are also found in air,
but in much smaller quantities. The proportions of water vapor and carbon dioxide in the
atmosphere vary, but are always very small.

nitrogen
(78%)

SOLAR ENERGY

argon
(0.93%)

In the Sun’s core, nuclear fusion reactions maintain a
temperature of 15 million degrees. This huge amount
ofenergy, constantly radiated into space in the form
of Etsthar s’sfaurtengr ci,syaaeh electromadneca
enables life to develop on the planet.

Solar radiationcrevoes th
entire electromagnetic
spectrum.

oxygen
(21%)

carbon dioxide
(0.03%)

The atmosphereand
clouds reflect 30% of
solar radiation.

weather balloon
(35 km)

supersonic jet
(18,000 m)

airliner
(11,000 m)

Mount Everest
(8,848 m)

The mesosphereis tkm) oldehe c8– 0(05reyal ts
of the atmosphere. At its outside edge, the
temperature is as low as –100°C.
50 km

THE LAYERS OF THE ATMOSPHERE

Earth’s atmosphere is made up of layers. The lowest ones (troposphere,
stratosphere, mesosphere) have a relatively homogeneous composition but
widely varying temperatures. In the thermosphere (80–500 km altitude), the
temperature rises considerably, since this layer absorbs considerable solar
radiation. Above it is the exosphere, a zone where the few remaining
molecules of air escape Earth’s gravity.

The temperature of the stratospheretheove t abj sumk,)5– 0(51
tropopause (–57°C), rises to 0°C because of absorption of solar
radiation by stratospheric ozone.

The ozone layer,m k30d detutialteewylb 0nane2 main,
intercepts much of the ultraviolet radiation directed toward
Earth.

15 km

The tropopauseb redrob eht sihe tenweet
troposphere and the stratosphere. Its altitude
varies depending on the season, the temperature
on Earth’s surface, the latitude, and the
atmospheric pressure.

The tops of cumulonimbush, reaccan uds col
and even go beyond, the edge of the troposphere.

The skylu bis rom eiaacsu eebterscatles lecu
mainly short-wavelength radiation, which
corresponds to the color blue in the visible
spectrum.

Most meteorological phenomena occur in the
troposphere(0–15 km), the part of the atmosphere
that contains almost all water vapor.

At sea levelf o,raperetuegarmet eht eva
the atmosphere is 15°C.

9

Earth’s atmosphere

Atmospheric pressure
The weight of air

Because molecules obey the laws of gravity, the molecules in the gases that make up
Earth’s atmosphere have a certain weight, which we bear constantly without being
aware of it. Atmospheric pressure is the force that air exerts by weighing on a given
area. At sea level, this pressure is equivalent to an average of 1,013 hPa, or 1.013 kg
2
per cm .
Earth’s atmosphere
Various factors, such as altitude and temperature, can create zones of high and
low atmospheric pressure. These variations are directly linked to major
meteorological phenomena.

10

HOW AIR PRESSURE IS MEASURED

The mercury barometer is used to measure atmospheric
pressure. Air presses on the mercury contained in a
reservoir, forcing it to rise in an evacuated tube. The
pressure exerted by the air is measured according to
the level reached by the mercury. For a long time, the
height of the mercury was the unit of measurement of
atmospheric pressure. Today, the International System
uses the hectopascal (hPa): 1,000 hPa is equivalent to
the pressure exerted by a 1 kg mass on an area
2
measuring 1 cm.

vacuum

THE INFLUENCE OF ALTITUDE ON ATMOSPHERIC PRESSURE

At sea level, the
height of the
mercury is, on
average, 76 cm.

tube

air pressure

mercury reservoir

The higher we go, the less air there is above us. Atmospheric pressure therefore drops with altitude. In the
lower troposphere, this drop is quite constant: about 1 hPa every 8.5 meters.

atmospheric pressure (hPa)
0
200
400
600
800
1000

14
12
10
8
6
altitude (km)
4
2
0

Jet planes, which fly at1 ,100 0 mlaitut,ed
are subjected to an atmospheric pressure of
about 200 hPa.

At the top of Mount Everest(8,488 m),
the atmospheric pressure is just above
300 hPa.

At sea leveland 15°C, atmospheric pressure
is, on average, 1,013 hPa.

HOW TEMPERATURE AFFECTS ATMOSPHERIC PRESSURE

air parcel

0Q

air molecule

0W

The heating of surface air Rppo eht etisoesusca
effect: molecules become more agitated and move
farther away from each other, which makes the air
parcel less dense. As it is lighter than the surrounding
air, the warm air parcel rises Tviea ang l,l
wopressure zone (depression) at ground level Y.

0R

When an air parcel cools Qmoe cules le iint ,ht
slow down. The air parcel contracts, becomes
denser and thus heavier, and descends toward the
ground Where it , wih ap-hgaerc setnezossree ur
(anticyclone) E.

0T

THE DISTRIBUTION OF ANTICYCLONES AND DEPRESSIONS
AROUND THE PLANET

In general, anticyclones (high-pressure zones) and depressions
(lowpressure zones) alternate around Earth in wide, relatively parallel
bands. This distribution, however, is affected by the presence of the
continents, whose land accentuates the warming or cooling of the air
masses above them.

North
America

South
America

Iceland

Africa

Siberia

Antarctica

In JanuaryQeht revo elttestsor ,nes yclonticng a
continents in the Northern Hemisphere, sitting
alongside the depressions over the northern oceans.
In equatorial regions, warm air rises and creates a
belt of depressions, particularly marked over the
continents. In the Southern Hemisphere, where
there is less land, tropical anticyclones are confined
to the oceans, while depressions sit over the
subpolar regions.

0Q

Pacific
Ocean

0E

high-pressure
zone

low-pressure
zone

0Y

ATMOSPHERICPRESSURE (hPa)

> 1032
1026–1032
1020–1026
1014–1020

Azores
Islands

Africa

1008–1014
1002–1008

996–1002
< 996

Asia

Australia

Antarctica

In JulyWatthei r hhet eaais,t sngA ni
maintains a huge low-pressure zone that extends
as far as Africa. The oceans in the Northern
Hemisphere are under high-pressure zones
(the Azores and Pacific anticyclones), but the
subpolar depressions have almost disappeared.
In the Southern Hemisphere, a broad
anticyclonic belt settles over all the tropical
regions, both continental and oceanic. The
lowpressure zone that sits above the Antarctic coast
varies little.

0W

11

Earth’s atmosphere

T h e m o v e m e n t o f
a i r m a s s e s

Fronts and depressions

An air mass is an enormous atmospheric volume that stays in a specific region and
has acquired climatic characteristics. As winds push the air masses, they come
into contact with each other and thus help to distribute humidity and heat around
Earth’stahtem sousrfpahceer een.t oft ehp al

12

When two air masses with different temperatures and humidity levels meet, they do
not mix, but collide along a line called a front. This encounter causes the formation
of clouds and precipitation.

nimbostratus
clouds

warm air mass

precipitation
warm front

cold air mass

COLD FRONT
A cold air mass that overtakes a
warm air mass produces a cold front.
The denser cold air slides under the
warm air, which is forced to rise
rapidly, forming cumulonimbus
clouds. Heavy precipitation,
sometimes with storms, develops.

cold air mass

occluded front

warm air mass

precipitation

WARM FRONT
When a moving warm air mass overtakes a cold
air mass, it creates a warm front. The warm air
rises,since it is lighter, becoming cooler as it
rises. The humidity that it contains condenses
in the form of nimbostratus clouds. This
configuration is often associated with
moderate precipitation.

cumulonimbus clouds

cold air mass

cold air
mass

cold front

warm air mass

heavy precipitation

OCCLUDED FRONT

An occlusion (or occluded front) occurs
when a cold front overtakes a warm
front: two cold air masses join,
surrounding the warm air mass and
pushing it upward.