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Discover more atwww.dk.com
DO
RLING KINDERSLEY
Discover more atwww.dk.com
DO
RLING KINDERSLEY
Eye Wonder
First American Edition, 2004 Published in the United States by
DK Publishing, Inc.375 Hudson Street
New York, New York 10014
04 05 06 07 08 10 9 8 7 6 5 4 3 2 1
Copyright © 2004 Dorling Kindersley Limited
All rights reserved under International andPan-American Copyright Conventions. No part of this
publication may be reproduced, stored in a retrievalsystem, or transmitted in any form or by any means,electronic, mechanical, photocopying, recording or
otherwise, without the prior written permission of thecopyright owner. Published in Great Britain by
Dorling Kindersley Limited.
A Cataloging-in-Publication record for this book isavailable from the Library of Congress.
ISBN 0-7566-0323-4
Color reproduction by Colourscan, SingaporePrinted and bound in Italy by L.E.G.O.
Discover more atwww.dk.com
Written and edited by Lorrie MackDesigned by Cheryl Telfer
and Helen Chapman
Publishing manager Sue LeonardManaging art editor Clare Shedden
Jacket design Chris DrewPicture researcher Sarah Stewart-Richardson
Production Shivani PandeyDTP designer Almudena Díaz DTP assistant Pilar Morales
Consultant Ben Morgan
4-5 What’s weather?
6-7 The seasons
8-9 The power of the Sun
10-11 Clouds in the sky
12-13 Cloud gallery
14-15 Living in a cloud
16-17 Rain, rain
18-19 White skies
20-21 Icy showers
22-23 Dew and frost
24-25 Blowing in the wind
26-27 Electric skies
LONDON, NEW YORK, MUNICH,
MELBOURNE, and DELHIContents
28-29 Terrible twisters
30-31 Deadly storms
32-33 Tricks of the light
34-35 Out at sea
36-37 Desert worlds
38-39 Weird weather
40-41 Weather forecasting
42-43 Changing climates
44-45 Harnessing weather
46-47 Glossary
48 Index and
acknowledgments
Thin skinIf the Earth were a huge apple,the whole atmosphere would bethinner than the skin. Drivingstraight through all its layers in a car, you would reachouter space in aboutthree hours.
“Weather” is what the sky and the airoutside are like—cloudy, snowy, sunny,or windy. A wide band of air—theatmosphere—surrounds Earth, butweather only happens near theground, below the cloud tops.This area is called the cloudlayer or troposphere.
What’s weather?
•Together, energy from the Sun andmoisture in the air create our weather.
•The air has lots of moisture in itbecause water covers 75 percent of Earth’s surface.
•Weather kills more people than anyother other natural force on the planet.
Weather facts
The clouds thatconstantly swirlaround Earth are clearly visiblefrom weathersatellites in space.
Troposphere
Stratosphere
Mesosphere
Thermosphere
Aurora(polar lights)
Meteor trails
Spacecraft
All our weather goes on in the layer of theatmosphere closest to Earth—the troposphere.
Satellite
Outer space
5
Out of this worldAbove the troposphere is thestratosphere. Here, because the
air is very dry, there is norain or wind. Pilots like
to fly at this levelbecause they can
be sure of asmooth ride.
Every day, we live withone of the most powerful
natural forces of all—our weather.
sun
rain
sn
ow
When an airplane flies above the clouds, thepassengers have a magical view from the windows.
wind
f rost
When one part of the world is basking in summer, another part is shivering in winter. This happens because Earth,which leans to one side, travels on along journey around the Sun.
On the tiltEarth is a round ball with an imaginary stick, or axis,running through the center(dotted red line). This axis istilted so one half of Earth getsmore sunlight than the otherat any one time, and istherefore sunnier.
JuneThe northern hemisphere is tilted towardthe Sun, so the people there are enjoyingsummer. South of the equator, there ismuch less sun, so winter is setting in.
MarchIt’s spring in the northernhemisphere, and fall at
the other end of the world.
The seasons
North and southThe equator is animaginary ring aroundEarth’s middle (yellowline). The area aboveit is called the northernhemisphere, while the
area below it is thesouthern hemisphere.
6
A year has 365 days because Earth
Ball of fireThe Sun is a fiery star made
of burning gas. We dependon it for light, heat, and
energy. Without theSun, there would be
no life on Earth.
SP R I N G
F A L L
Axis
WIN T E R
SU M M E R
Equator
Constant heatThe places near theequator are always sunny,so the temperature iswarm all year.
DecemberIn December, the northern hemisphere leansaway from the Sun, so it’s winter there. But the Sun is stronger down south, so it’s summer.
SeptemberSeptember brings fall
to the northernhemisphere, and
spring to thesouthern hemisphere.
7
takes this long to go around the Sun.
There are 24 hours in one day.
NIGHT
DAYDAY AND NIGHT
As well as moving around the Sun, Earthturns once on its axisevery 24 hours. We haveday and night becausedifferent sides of it face theSun at different times.
F A L L
WIN T E R
SU M M E R
SPR I N G
8
Earth is constantly bombarded with rays from theSun—a huge ball of burning gases in space. Aswell as producing heat and light, the Sun controlsEarth’s weather.
The power of the Sun
Warmth and waterHeat from the Sun turnsthe moisture from leafytrees and plants intoinvisible water vapor inthe air. The same thinghappens with the waterin lakes and oceans.
Clouds Moisture hovers in the
sky in the form of clouds.When the clouds get full,the tiny droplets in them
stick together andbecome drops of rain.
Water sometimesdisappears into theair and becomeswater vapor. Thisprocess is calledevaporation.
9
WindThe Sun’s rays warm pocketsof air, which causes them torise. Cool air then rushes in tofill the gap. This movementof air is what we call wind.
RainWater from clouds falls as rain.
If the air is cold enough, themoisture turns into snowflakesinstead of raindrops. Whateverform it takes, all moisture that
falls to the ground is calledprecipitation.
Starting againSome rain and melted snow flow back into ourrivers and oceans. This water is called runoff.Soon it will evaporate into clouds again.
•If all the Sun’s energy couldbe harnessed for one second, itwould power the United Statesfor 9 million years.
•Earth is a tiny dot comparedwith the Sun, which is bigenough to swallow our planeta million times.
Sunny facts
10
Clouds in the sky
Stratus Of all the main types, stratus cloudsare lowest in the sky. Sometimes theysit right on the ground to form fog.Although stratus means “layer,” the layers aren’t always clear—often, stratus cloudsjust make the skylook gray.
Clouds are made from drops of water. Theamount of water in each cloud, its height, andthe air temperature determine what kind it is.There are three main types—stratus, cumulus,and cirrus—and lots of combinations of these.
•In Latin, stratus means layer, cirrusmeans hair, and cumulus means heap.
•Clouds that have “nimbus” or “nimbo”in their name are rain clouds.
•Clouds that have “alto” in their name form at a medium height.
Cloudy facts
Cumulus These clouds are plump andfluffy like cotton balls. Smallwhite ones appear on clear,
sunny days, but cumulusclouds that are big and black(called cumulonimbus) mean
rain or snow storms are onthe way.
Stratocumulus cloudshave layers as well as thebumpy surface of cumulus
clouds. Their soft grayshapes often producedrizzle or light rain.
Sky map Clouds are named according totheir height and how they’reformed. Even those thatlook quite similar canhave different namesat different heights.
Cirrocumulus clouds are a cross between cirrusand cumulus types. When their regular waves of
tiny cloud clumps form a pattern that looks likefish scales, we call this a “mackerel sky.”
Cirrus High, wispy, feathery cloudsare called cirrus. Here, the air
is so cold that clouds aremade from ice crystals
rather than waterdrops. Sometimes,strong winds blowthem into longstrands or “mare’stails” because they
look like horse’s tails.
Nimbostratus
Stratus
Cirrocumulus
Cirrostratus
Some
cumulonim
bus clouds
are7
miles (11
km) tall.
Altostratus
Airplane contrail
Cumulus
Stratocumulus
Cumulonimbus
Cirrus
12
There is nothing unusual about cloudyskies—most of us see them all the time.But we might be surprised if the cloudslooked like flying saucers, sheets of water,or clusters of colored lights.
Human-made cloudsWhen jet planes crisscross thesky, they leave behind long,straight tails of vapor that look like clouds. These areknown as contrails.
Painted cloudsWhen sunlight passes through the waterdroplets or ice crystals in a cloud, it canproduce beautiful shimmering colors.
Wavy nightsClouds that appear at night
and look like waves on the seaare called noctilucent clouds.
The name “noctilucent” comesfrom the Latin words for
“night” and “shine.”
Cloud galleryAgainst a blue sky,contrails sometimeslook like city streetsmade of clouds.
13
Bumpy warningThe peculiar rounded shape of thesestorm clouds gives them their name.They’re called mammatus clouds, from“mamma,” the Latin word for “breast.”
Mammatusclouds areoften a signthat there’s atornado onthe way.
All these bumps arecaused by downdrafts of air.
Flying cloudsLenticular clouds got their namebecause they look a little likelenses, but some of them lookmore like flying saucers!
Sauc
er-sh
aped clouds can “hover” for hours.
Rolling in When warm, damp air blows over
cold land or a cold ocean current, itsmoisture turns into fog. This type is
called advection fog.
The Golden Gate Bridgein San Francisco is oftensurrounded by fog.
Sometimes it’s so foggy outside, you feelas if you’re walking through a cloud. Ina way, you are! Fog is actually a cloudthat is sitting on the ground instead offloating in the air. There are severaldifferent ways fog is made.
Living in a cloud
mist is just finer and lighter
Experts describe fog in terms of “visibility”—how far you can see through it.
•In ordinary fog, you can seefor about 1,100 yd (1000 m).
•In thick fog, you can only see 55–220 yd (50–200 m).
•In dense fog, you can see for less than 55 yd (50 m).
Foggy facts
Mist and fog are different types of
14
Hazy daysWhen the ground loses(radiates) heat and getsvery cold, it cools the airabove it, making watervapor condense into finedroplets. This creates themost common type of fog,known as “radiation” fog.
Mountain mistOn wooded hills,moisture given off bytrees turns into fogduring the night. Bydawn, it has settled intothe valleys below. Later,when the Sun warms the air, this moistureevaporates, and the fog clears.
Poison airWhen fog combines with
smoke, it forms heavy, smellyair. Years ago, London,
England, had fogs so thickthat people called them
“pea-soupers.” This fog came from the dirty coal fires that
heated most buildings. Today,similar conditions, known as
smog, are caused by pollutionfrom cars and factories.
than fog.
the same thing—
15
How much rain?Scientists measure rain in a simplegauge set into the ground. Afterthe drops fall through the funnelat the top, they arecollected in the maincylinder below.
17
Clouds are made of tiny dropletsof water. When a cloud takes on more and more moisture, thedroplets get bigger. Eventually,they get so heavy that they fall tothe ground as drops—small onesare called drizzle, and big, heavyones are called rain.
Rain, rain
•On the Hawaiian island of Kauai, there are only about15 days in the year when itdoesn’t rain.
•Drizzle falls more slowlythan rain, since it is muchfiner. It takes about 700 drizzledrops to make one raindrop.
Rainy facts
Poison rainWhen chemicals pour into the air from
factories and cars, they react with watervapor to form harmful acids. The result—
acid rain—kills forests, poisons water,and even wears away stone.
Falling shapesMost people thinkraindrops are shapedlike teardrops, but theyactually look more like squashed buns.
Deadly showersHeavy rain can cause terrible floods thatdestroy life and property. When storms hit theZacatenco River in Mexico, its raging watershad enough power to bring this bridge down.
Scary skiesRain clouds hold a huge amount ofwater, which makes them so densethat light can’t get through. This iswhy they look dark and scary. Theheaviest rain falls from the biggest,
blackest clouds.
New raindrops are round,but they flatten outgradually as they fall.
Arica, Chile0.03 in (7 mm)
Kauai, Hawaii460 in (11,680 mm)
New York44.5 in (1,130 mm)
London, England24 in (610 mm)
Berlin, Germany23 in (580 mm)
Cairo, Egypt1 in (25 mm)
Average yearly rainfall
18
When the air is cold, themoisture in clouds freezes into ice crystals without turning into rain first. These crystals stick together and float to the ground as snowflakes.
White skies
Swirling curtainWhen snow is coming down thick and fast, we call it ablizzard. Sometimes, even when a blizzard is over, wind whipsup the snow on the ground so it seems like it’s still falling.
In a really bad blizzard,people can hardly seewhere they’re going.
There can be as manyas 200 ice crystals inone snowflake.
White laceMost snowflakes looklike lacy, six-pointedstars, but some havevery different shapes.
•Snow is so important tothe Inuit that they have over100 words for it, includingpiqsig (blowing snow) andauviq (good snow for igloos).
•In April 1921, 6 ft 4 in(1.93 m) of snow fell in24 hours at Silver Lake,Colorado.
Snowy facts
Cozy snowThe Inuit people of the Arctic build small hutsfrom blocks of snow. These temporary shelters,
which they use like tents, are called igloos.
Look out below!Layers of snow canbuild up so high that a slight movement can tip them over.Tumbling, crashingsnow like this is calledan avalanche.
Cold and dryThe heaviest snows fallwhen the temperatureis just below freezing.Very, very cold places hardly ever get any snow.
Most snowflakes looklike stars. This shapeis described as stellar,meaning starlike.
Snowflakes with six flatsides are called plates.
Columns are long,hollow flakes of snow.
A big avalanche can bury peopleand buildings in seconds.
Fallen snow looks like a whi
te
blanket.
Fallen snow looks whiteand sparkly because itreflects nearly all thelight that hits it.
19
20
Icy showers
Icy missilesSmall hailstones are round and white, butbigger ones usually have knobby shapes andjagged surfaces. The largest hailstone everrecorded measured 17 in (43 cm) across.
Birth of a hailstoneInside huge storm clouds,strong, freezing windswhirl around constantly.Any ice crystals insideget tossed up and down,building up more andmore frozen layers oneach crystal. Theselayers turn the tinycrystals into hailstones.
Thes
e hailstones are as bigas te
nnis
balls
!Giant hailstonescan smash throughroofs, hurt people,and flatten crops.
An
ice
crys
talg
etsca
ught
inan
updr
aft.
When solid pellets of ice fallout of the sky, we call it hail. Some hailstones are about the size of plums, and others are smaller than peas.
Then it falls, collecting
21
Falling dangerA single hugehailstone shatteredthis windscreen.The air at the
top of a cloud iscolder than theair at the bottom.
until it falls out ofthesky.
Road risk Driving through
a hailstorm can bedeadly. It’s hard to see,
the road is slippery, andreally big hailstones candamage cars and trucks.
Each roundtrip
addsanother
layerof ice.
The
iceballkeepsgetting
biggerandbigger
Up
itgo
esag
ain,
freez
ing
atth
eto
p.
moisture
onthe w
ay.
Fern frostWhen damp aircomes in contact with cold glass, the water vaporturns to ice crystals.These look like finelace, or the feathery,ferny leaves thatgive this frost its name.
On cool nights, moisture in the air turnsinto water as it drops to the ground,covering everything with morning dew.On freezing cold days, it hardens as frost.
Dew and frost
Nature’s glazeIf the temperature falls after thedew has settled, the moisture oftenfreezes into a covering of clear,smooth ice, like on these berries.
Dawn sparkleOn cool mornings, you willfind glittery drops of dewcovering every surface. Onthis delicate spiderweb, the dewdrops look like tiny jewels.
Hoar frostAs water vapor in the air touches frozen surfaces,it sometimes forms spiky ice needles instead of asmooth coating. These spikes are called hoar frost.
23
JACK FROST
When feathery shapes appear onwindows, and the landscape is white andsparkling, children are told that Jack Frosthas been at work with his paintbrush. Jackfirst appeared in Norse lore as Jokul Frosti(meaning “icicle frost”), son of thewind god Kari. In Europe andNorth America, he is usuallyshown as a mischievous elf.
Rime frostDuring very cold weather, icy windscreate a crusty coating called rimefrost on wet leaves and branches.Because it forms so quickly, rimeis thick and hard, with a surface
that looks like sugar.
Air is restless and moves all the time. When itmoves quickly enough for you to feel it on yourface, it is called wind. Some winds blow all bythemselves in one place—others are part of abig, wavy pattern that covers Earth.
Blowing in the wind
Wispy clouds caughtin the jet streamover north Africa.
Spinning airWhen clouds getcaught up in wind,their graceful patternsreflect the swooping,swirling way airsometimes moves.
Magic windsBands of high winds calledjet streams go aroundEarth from west to east.They are so strong thatpilots can cut hours offtheir flight times if they fly along with them.
Powerful forceIt takes strong, steady winds to make a tree grow likethis. The winds don’t actually bend the trunk, though.They kill all the shoots, buds, and leaves on the side thatfaces the winds, so only the protected side can grow. W
ind
isju
stm
ovin
g air.
NORTH POLE
SO
UTHPOLE
Near the equator,winds blow from the
east. Farther away,they change direction.
Many sand sculpturesare top-heavybecause wind tendsto wear away therock near the ground.
Winds of the worldThe Sun’s heat and the way Earth turns create wind patterns. These are so reliable thatsailors used them for centuries to cross the oceans.
Blown awayWhen desert sand is blown around by fierce winds, it can wear away solidrock. This leaves weirdshapes that look likemodern sculpture.
Westerly winds
Jet streams
Easterly winds
the strongest are gales.
•When a cold wind is blowing, thetemperature feels much lower than it really is. This effect is called thewind-chill factor.
•Wind is measured according tothe Beaufort scale, first developedfor use at sea. This scale has 13points: Force 0 is calm and Force 12 is a hurricane.
Windy factsThe lightest winds are called b r e e z e s —
NORTH POLE
SOUTHPOLE
26
Lightning moves at a speed of 23,000 miles per second
(37,000 km per second).
Chosen pathsLightning can flash– inside a single cloud– between a cloud andthe air nearby– between two clouds– between a cloud andthe ground below
Lightning bolts are hugeelectrical charges createdwhen the ice and waterinside storm clouds rubtogether. More than3 million of them flashacross the skies every day.
Electric skies
•Thunder is the noise lightningmakes, but we don’t hear it rightaway because light travels fasterthan sound.
•One fork of lightning carriesenough electricity to light awhole town for a year.
•The names of two of Santa’sreindeer, Donner and Blitzen,are the German words forthunder and lightning.
Lightning facts
27
Lightning bolts canbe up to 4 miles(6 km) long.
Direct hitAlthough a lightning bolt lastsonly a fraction of a second, itsheat is so intense that it can setfire to a building or a tree.
Danger!Never shelter from a storm
underneath a tree, sincelightning is attracted to
anything that stands highabove the ground.
When lightning flashes, itmakes the air five times as
hot as the Sun’s surface.
28
Tornadoes are terrifying funnels ofspinning air. They contain super-fastwinds with deadly power to smashhouses, flip cars over, and knocktrains off their tracks.
Terrible twisters
Birth of a monsterTornadoes begin as warmair drawn into the base ofhuge storm clouds. Warmair is lighter than cool air,so it rises quickly. Then,like water flowing into a drain, it starts to spindown. If it spins fastenough, it touches theground in the form of a deadly funnel. Tor
nado
war
ning!
• At the center of a big tornado, thewind can reach 250 mph (400 km/h).
• A tornado can flatten one house, and leave the one next door standing.
• During a 16-hour period in April1974, 148 twisters hit “Tornado Alley” in the central US, killing 315 people and injuring 5,484 more.
Tornado facts
Tracking the twistersBecause they destroy anyinstruments in their path,
tornadoes are hard to study.Special radar dishes
mounted on the backs ofhuge trucks help to work
out where they are going.
Tornado AlleyThere are more tornadoes inthe central United States thananywhere else on Earth. In the area where they are mostcommon—nicknamed “TornadoAlley”—most houses have astorm cellar or basement wherethe family can take cover if atornado is on the way.
This tangle of crushed metal wasonce a large, heavy truck.
Death and destructionTornadoes destroy property, nature,and human life, all within minutes.Here, a quiet town in the state ofGeorgia has been torn apart.
29
Radar devices like this one can detect signs of a tornadodeveloping inside a storm cloud.
30
At the center of everytropical storm is a smallpatch of calm called theeye. The strongest anddeadliest winds of all spinaround the eye of the storm.
Photographed from space,Hurricane Fran movesacross the Caribbean Seatoward Florida in 1996.
Deadly stormsHurricanes are the most violent anddevastating storms on Earth. Theyalmost always start in tropical places.In different parts of the world,hurricanes are alsoknown as typhoonsand cyclones.
Monstersfrom the seaHurricanes get theirpower from the heat oftropical seas and the factthat Earth turns fastest near
the equator. They start assmall storms, then build
into swirling clouds ofwind and rain.
Fatal windWhen Andrew did reach land
(known as “making landfall”), itflattened everything in its path.
In total, it killed 65 people anddestroyed more than 25,000 homes.
Run for cover!When scientists expect a huge storm,
they advise people to leave nearbytowns and cities. Here, residents of
Florida head for safety beforeHurricane Andrew hit in 1992.
Lethal waterHurricanes whip up high,pounding waves. Thesecause huge damage alongnearby coasts and forsome distance inland.
• Hurricanes are graded from 1 to 5. Number 1 is a storm thatcan cause slight damage, while 5 means a potential disaster.
• Since the 1940s, hurricaneshave been given human names.At first they were girls’ namesonly, but since the 1970s, boys’names have been used one year,and girls’ names the next.
Stormy facts
32
Tricks of the light
Magic dropsRainbow colors always
appear in the same order. Redis at the top, then orange, yellow,
green, blue, and indigo, with violetat the bottom. The bigger the
rainbow, the brighter andsharper the colors will be.
Every day, the Sun puts on light shows far moredramatic than anything technology has to offer.
As well as multicolored rainbows, it can createmagical icebows, shimmering auroras,
and glowing spots in the sky.
Ancient legends describe a pot of gold at the end of every rainbow.
MAGIC DROPS
Light is made up of seven colors. These are the colors we see in arainbow. When the Sun shines through raindrops, its light bends
and reflects off their surface. The different colors bend at different angles, though. This
separates theminto the layeredbands of lightwe call arainbow.
33
Mock moonIf ice crystals fallthrough theatmosphere atnight, theyproduce asundog-like
effect beside themoon. These spots
are called moondogs.
Frozen lightAt the poles, the airis always freezing, so clouds are madeof tiny ice crystalsinstead of watervapor. Inside thesecrystals, light has no room to separateinto colors, soicebows look white.
Dazzling displaysOften called “northern
lights” or “southernlights” because they
appear at the north andsouth poles, auroras are
vast sheets of greenstreaked with pink and
blue. They are caused byelectrical storms on the Sun.
Second SunFalling ice crystals are able to bend the Sun’s rays likeraindrops do. This createslarge bright spots that lookalmost like another Sun. Suchspots are called sundogs.
The ingredients that make up ourweather—like temperature, water, andwind—work in the same way at sea asthey do on dry land. But the end resultsare often very different.
Out at sea
Winds and wavesThe winds that blowover our oceans arereally strong becausethere are no largeobstacles to slow them down. Thesepowerful winds pushthe seawater intowaves. During bigstorms, huge wavescan reach the top of a lighthouse.
•One side of a ship is alwayswindier than the other. This iscalled the windward side; thesheltered side is the lee.
•When seawater freezes intoice, it’s not salty any more—all the salt is left in thesurrounding water.
Watery facts
35
Iced waterIcebergs are huge chunks of ice that havebroken off glaciers at the north and southpoles. Here, the seas are so cold that icebergscan stay frozen for hundreds of years.
Fog banksIf warm, moist air blows over cold seas, thick fog forms in highmounds called banks. This fog isvery dangerous for sailors, sincethey can’t tell where they’re goingor what’s in front of them.
WaterspoutsWhen they form at sea, whirlwinds and
tornadoes are called waterspouts. Thebiggest ones can suck up so much water
that ships in the area get sucked up, too.
Centuries ago,sailors thoughtwaterspouts wereblown by hugesea monsters.
You can only see the tip of aniceberg—most of it is underwater.
Seeing thingsHeat rising up from the ground can make lightshimmer so it looks like shallow water. Thisfalse image is called a mirage.
Green islandsAn island of greenery called an oasissometimes springs up in the middle of adesert. This happens when undergroundsprings seep up to the surface, making itpossible for plants to grow.
Rainy days may make you miserable, but peoplewho live in desert regions would give anything to
get wet. Deserts—which can be cold as wellas hot—are places where there is
almost no rain at all.
Desert worlds
Whirling cloudsWhen desert ground gets hot,the air above it can swirl upwardto form spirals as high as 350 ft(100 m). If dust or sand is suckedinto these whirlwinds, they’reknown as dust devils or sanddevils. Australians call them“willy-willies.”
Thirsty stems Desert plants are specially adapted for dryweather. Cacti, for example, are thick and
fleshy so they can keep moisture insidethem for a very long time.
Dry storms A lot of desert land is made of sand instead ofsoil. When the wind blows hard, it createsswirling clouds of choking, blindingsand and dust. At their worst,
sandstorms cause more damagethan the thickest blizzards.
•The driest place on Earth isthe Atacama Desert in Chile,where it only rains about onceevery six years.
•Some deserts are coveredwith sand dunes. These moveconstantly in the wind, so noplants can take hold. Evenborders between countriescan’t be marked clearly.
Desert facts
Desert travelers often thinkthey see water in the distancewhen there is really only sand.
38
Blankets of blackAs volcanic clouds spread,they block out the Sun.This dark sky hung overthe Philippines in 1991,when Mount Pinatuboerupted, coveringeverything ingray ash.
No matter how much we learn aboutthe weather, it can still come up witha few surprises. Have you ever seena mud shower, an ice storm, or a black sky in the afternoon?
Weird weather
Exploding EarthWhen hot gas and liquid rockburst through Earth’s surface, we call it a volcano. Theseexplosions pour huge amounts of dust and ash into the air.
Mischievous boyEvery few years, a warm oceancurrent appears off SouthAmerica. Known as “El Niño”(the Boy Child) because it comes at Christmas, this currentupsets weather systems all overthe world.
It’s raining mudWhen dust storms (or volcanicdust and ash) get mixed upwith rain, the result is fallingmud. This messy shower isanother result of MountPinatubo’s 1991 eruption.
Ice stormsRain that falls through freezing air forms
a layer of clear ice when it lands. Thiscoating or glaze can be heavy enough to
bring down telephone and electricity poles.When these lines came down in Oklahoma,
thousands of families lost their power.
Angry oceanEl Niño warms the seas off California. Thiscauses violent storms along the coast and as farinland as Nevada, two hundred miles away.
Nobody wants to have a picnic in the rain,or go to the seashore when it’s cloudy andcold. To help us make plans, we dependon weather forecasts. Daily forecasts arequite accurate, but figuring out what the weather will do overweeks and months ismuch harder.
Weather forecasting
Up, up, and awayWatched by curious penguins, this scientist isreleasing a weather balloon over Antarctica.The instruments attached to it measuretemperature, wind, and moisture, and radio the results back to Earth.
40
Ground stationsAll over the world—on land, as shownhere, and in themiddle of the sea—weather stationsgather information.This is then passed onto scientists inindividual countriesso they can forecasttheir weather.
This weather station is locatedin the state of Idaho.
•Weather balloons risebecause they’re filled withhydrogen or helium gas, which are both lighter than air.
• Hygrometers measuremoisture in the air. The firstone was built by Leonardo da Vinci in the 1400s.
Forecasting facts
View from spaceShown as a bright greenswirl on this satellite image,a hurricane hits the Gulfcoast of the United States.
Spy satellites Hundreds of weather satellitesorbit Earth, recording picturesand data. Some move at thesame speed as Earth turns, so they stay above one spot. Others flyaround the planetfrom pole to pole.
Weather wizardryHuge supercomputers take in weatherdata from all available sources. This isfed into a model of our atmosphere so
the computer can work out what effectit will have on the weather.
The
first
wea
ther
sate
llite
s werelaunched in the late 1950s.
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Poison in the airThese Italian children wear protectiveclothes to protest against trafficpollution. Scientists think toxic gasesfrom cars and factories trap too muchheat in the atmosphere. Because theyact like glass in a greenhouse, theyare called “greenhouse gases.” Theprocess is known as “global warming.”
Changing climatesThe world’s weather changes naturally overtime. But experts are afraid that pollution isdamaging our atmosphere and altering ourclimates in a bad way.
Burn
ing coal creates pollution.
Po
llution leads to global warm
ing.
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Black powerAlong with exhaust fumes from cars, trucks, and buses, a mainsource of air pollution is smoke. Fossil fuels (like coal) createthe most smoke when they are burned to produce electricity.
Protect our planetWhen we recycle
household waste likepaper and bottles, wedon’t need to burn so
much fossil fuel tomake more.
Rising waterWhen the temperaturerises by even a little,polar ice caps start tomelt and affect ouroceans. Scientists areafraid that if too muchice disappears, polarbears will lose much oftheir hunting ground.
Dangerous exposureAs well as warming the air,pollution damages the layerof ozone that surroundsEarth. Ozone is a bluish gasthat helps to block out the
Sun’s ultraviolet rays.
The light blue on this globe is the ozone layer. The bigdark hole over Antarctica
has been caused by pollution.
There are holes in the ozone layer at bothno
rthan
dso
uth
pole
s.
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• We could reduce globalwarming if we made better use of energy from sunlight, wind,and waves (see next page).
• Buying smaller cars—andwalking when we can—will alsohelp us to reduce greenhousegases because we won’t createso many exhaust fumes.
Warming facts
Whether it feels like a friend or an enemy,weather is something we usually can’tcontrol. But today’s scientists arelearning how to convert its awesome power into
cheap, clean energy.
Ancient knowledgeFor centuries, wind has
carried balloons and kites throughthe air, and pushed sailing shipsacross lakes and seas.
Harnessing weather
Passengers andequipment travelin a small basketsuspended fromthe hot-airballoon.
Sola
rpo
wer
stat
ions
need
tobe
built
insu
nny
plac
es.
Catching the SunOn solar power stations, huge mirrors concentratethe Sun’s rays. For now, though, this technologyproduces quite a small amount of energy.
Powerful facts
•Electricity generated by water—waves, tides, or waterfalls—isknown as hydroelectric power.
•The biggest solar power stationin the world is in the MojaveDesert in California.
•A large area of land coveredwith wind turbines is called awind farm.
Wave powerRemote areas like the Scottish
island of Islay often have nopower stations. Here, harnessing
the force of crashing waves is agood way to produce energy.
Puffs of windThese tall turbines are modernwindmills that create energy.But like solar power, windpower can produce only a smallamount—it takes about 3,000turbines to equal the output ofone coal power station.
Machinery designed to harness waves hasto withstand theroughest seas.
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Current a ribbon of movingwater in an ocean.
Desert a dry region that getsvery little rain.
Dew drops of moisture thatcondense near the ground after a cool night.
Equator an imaginary linearound the middle of the Earth,between the two poles.
Evaporation what happenswhen liquid disappears into theair to become water vapor.
Fog a cloud that is sitting onthe ground. Fine fog is calledmist; fog mixed with smoke iscalled smog.
Acid rain rain that has beenpoisoned by pollution.
Atmosphere the wide, layeredband of air that stretchesbetween Earth and outer space.
Aurora bands of colored lightthat appear in the sky over thenorth and south poles.
Blizzard a storm in which thicksnow falls fast and hard.
Cloud a mass of water dropletsor ice crystals in the sky.
Condensation what happenswhen water vapor in the airturns to liquid.
GlossaryHere are the meanings of some words that are useful to
know when you’re learning about the weather.
Golden glowThe sky sometimes turns deep red orgold when clouds of dust float up intothe atmosphere. The old rhyme belowsuggests that a fiery sunset means fineweather the next morning, while a fierydawn means storms are on the way.
Red sky at night, sailors’ delight;
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Lightning a flash of staticelectricity in the sky.
Precipitation moisture releasedfrom the air onto Earth’ssurface. Rain, snow, hail, fog,and dew are all forms ofprecipitation.
Pollution any substance thatmakes air, soil, or water dirty orpoisonous.
Rain drops of condensed waterthat fall from a cloud. Small,fine droplets of rain are knownas drizzle.
Freezing what happens whenwater turns into solid ice at32˚F/0˚C.
Frost ice crystals that formwhen moisture in the air freezes.
Global warming the gradualincrease in temperature ofclimates around the world.
Hail pellets of ice that fall tothe ground from storm clouds.
Hurricane a powerful stormthat brews up over tropicaloceans. In different parts of theworld, hurricanes are calledtyphoons and cyclones.
Ice water that gets so cold it is frozen solid.
Rainbow bands of colored light that form when raindropsreflect the Sun.
Snow clusters of ice crystalsthat freeze directly from vapor,without turning into drops first.Ice crystals stick together toform snowflakes before they fall.
Tornado a spiral of air whirlingupward at very high speed.
Troposphere the layer ofEarth’s atmosphere directlyabove the ground. All weathertakes place in the troposphere.
Wind the movement of airfrom one place to another.
Red sky in the morning, sailors take warning.
acid rain 17atmosphere 4-5, 41, 42auroras 4, 32-33axis, Earth’s 6-7
blizzards 18, 37
clouds 4, 8-9, 10-11,12-13, 14-15, 16-17,18-19, 20-21, 24-25,26-27, 28-29, 30-31,32-33
cirrus 10-11cumulus 10-11lenticular 13mammatus 13nimbus 10-11noctilucent 12 stratus 10-11
contrails 11, 12currents 39cyclones 30-31
deserts 36-37dew 22-23drizzle 10, 16-17dust devils/storms 37, 39
energy 44-45equator 6-7, 25, 30
rain 5, 8-9, 10-11, 16-17,30-31, 36-37, 39rainbows 32-33
sand devils/storms 37seasons 6-7smog 14-15 snow 5, 9, 18-19space 4, 30 stratosphere 4 Sun 4-5, 6-7, 8-9, 14-15, 24-25, 26-27, 32-33, 38, 43, 44-45sundogs 33
thunder 26-27 tornadoes 13, 28-29 troposphere 4-5typhoons 30-31
volcanoes 38
waterspouts 34-35waves 31, 34, 43, 44-45weather stations 40-41wind 4-5, 9, 11, 18-19,24-25, 28-29, 30-31,34-35, 36-37, 40, 43,44-45wind-chill factor 25
Index
48
fog/mist 10, 14-15, 35forecasting 40-41frost 5, 22-23
global warming 42-43greenhouse gases 42-43
hail 20-21 hurricanes 30-31, 41
ice 18-19, 20-21, 22-23, 26-27, 32-33,34-35, 39icebows 32ice caps 43ice storms 38-39
Jack Frost 23jet streams 24-25
lightning, 26-27,
meteors 4moondogs 33mud showers 38-39
Niño, El (current) 39
ozone layer 43
poles 6-7, 24-25, 32-33,41, 43pollution 42-43, 44-45
Dorling Kindersley would like to thank:Janet Allis for her original Jack Frost illustration; Laura Roberts forher help with the main Season’s artwork; Fleur Star for her generaleditorial and research assistance, and Penny Arlon for proofreading.
Acknowledgments
Picture creditsThe publisher would like to thank the following for their kindpermission to reproduce their photographs:(Key: a=above; c=center; b=below; l=left; r=right; t=top)
Alamy Images: Brand X Pictures 6-7; Bryan & Cherry AlexanderPhotography 19br, Steve Bloom Images 4-5a; Cameron Davidson31b; EuroStyle Graphics 12bl; Dennis Hallinan 14-15; ImageState 3r, 21; Hans-Peter Moehlig 12tl; Plainpicture 43br; A. T.Willett 21br, 26-27b, 19trb; Jim Zuckerman 28. Ardea LondonLtd: Eric Dragesco 19cl; Steve Hopkin 22bl. Bruce Coleman Ltd:11tr. Corbis: 8t, 10-11; Phil Banko 36tl; Tom Bean 25tr; Gary W.Carter 22c; 1996 Corbis/Original image courtesy of NASA 24tl,24cr; Rick Doyle 34-35; Frank Lane Picture Agency 20tl, 41tl;Raymond Gehman 15bl; William Manning 8-9; John M. Roberts5bra; Galen Rowell 13br; Scott T. Smith 23; Ray Soto 35tr;Stocktrek 41cr; Hans Strand 43tr; Sygma 29cr; Craig Tuttle 22tl;
Martin B. Withers; Michael S. Yamashita 18. FLPA - Images ofnature: C. Carrolho 33b; Tom & Pam Gardner 36bc. GettyImages: Alejandro Balaguer 38bl; Jose Louis Banus-March 48l,r;Tom Bean 9t; Rob Casey 5br; J.P. Fruchet 24-25, 48c; Jeri Gleiter44tl; Lester Lefkowitz 45tl; Yannick Le Gal 34l; Jens Lucking 5tr;Nadia Mackenzie 44-45; Graeme Norways 10c; Pascal Perret 16-17; Colin Raw 42-43; Ulli Seer 46-47; Erik Simonsen 26-27t;Oliver Strewe 17tl; Harald Sund 35tl; John Wilkes 16l. MasterfileUK: Allan Davey 27tr. Nature Picture Library Ltd: GrantMcdowell 37bl; Anup Shah 1. NASA: 6tr, 6bl, 7tr, 7br. N.H.P.A.:Ant Photo Library 36-37. Oxford Scientific Films: 39cl;Weatherstock 29tl. Pa Photos: 17r. The Palm Beach Post/GregLovett: C J Walker 31c. Jeff Piotrowski/Storm Productions: 29br.Planetary Visions: 41b. Popperfoto: 15cr. Powerstock: WalterBibikow 32; Fabio Muzzi 15t; Stock Image 10bl. Reuters: 29bl. RexFeatures: Sipa Press 38-39, 39tl; Son 27br. Science Photo Library:18tlb; Martin Bond 45cr; Alan L. Detrick 5cr; David Ducros 4-5b;Jack Finch 33tr; Simon Fraser 11tl; R.B.Husar /NASA 39cr; TedKinsman 19tcb, 19tl; NASA 30, 43c; Stephen J. Krasemann 33c;Pekka Parviainen 12-13, 22br; Claude Nuridsany & MariePerennou 2tc, 18tl, 18tlbr, 19tl, 19tc, 19tr; George Post 20-21; JimReed 20l, 21tr, 41br; Francoise Sauze 13tr; David Vaughan 33cl.Still Pictures: 39br; Denis Bringard 5trb; Angelo Doto 42l; RolandSeitre 40-41.
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