climate and weather state correlation 4c, 4h, 4d 1

Climate and WeatherClimate and Weather

State Correlation 4c, 4h, 4dState Correlation 4c, 4h, 4d

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Climate and WeatherClimate and WeatherPart A: The AtmospherePart A: The Atmosphere

Chapter 16 section 1 and 2Chapter 16 section 1 and 2

Mini Video Clip: National Mini Video Clip: National Geographic Weather 101Geographic Weather 101

http://video.nationalgeographic.com/video/kids/forces-of-nature-kids/weather-101-kids/

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DiscussionDiscussion

How does weather affect How does weather affect your everyday life?your everyday life?

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16:1 The Air Around You16:1 The Air Around You Surrounding the Earth is a layer of gas called Surrounding the Earth is a layer of gas called

the the atmosphereatmosphere WeatherWeather is the condition of the atmosphere is the condition of the atmosphere

TemperatureTemperature Air PressureAir Pressure HumidityHumidity WindWind CloudsClouds PrecipitationPrecipitation

Weather Weather changeschanges from day to day & place to from day to day & place to placeplace Main cause for changes is energy from the Main cause for changes is energy from the sunsun

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16:2 Air Pressure/Barometric 16:2 Air Pressure/Barometric PressurePressure

Because air has mass, it also has Because air has mass, it also has other properties, including: density other properties, including: density and pressureand pressure

The amount of mass in a given unit of The amount of mass in a given unit of volume is volume is densitydensity

Density can be calculated by dividing Density can be calculated by dividing the mass of a substance by its the mass of a substance by its volume;volume;

Density = mass/volumeDensity = mass/volume

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Draw this in your notes

Air PressureAir Pressure

The force pushing on The force pushing on an area is an area is pressurepressure

The atmosphere exerts The atmosphere exerts a force on the surfacea force on the surface

Air pressure Air pressure is the is the result of a column of result of a column of air pushing down on air pushing down on an area an area seefigure 4 p535seefigure 4 p535

How does the density of air affect Air pressure?How does the density of air affect Air pressure?66

Air Pressure/Barometric PressureAir Pressure/Barometric Pressure

The instrument used to measure air The instrument used to measure air pressure is the pressure is the barometer.barometer.

There are two kinds of barometers, the There are two kinds of barometers, the mercurymercury barometer and the barometer and the aneroidaneroid barometer (see figures 5 and 6 p. 536-7)barometer (see figures 5 and 6 p. 536-7)

What are two common units that are used to measure air pressure? (see pg. 537) 77

Altitude and Air PressureAltitude and Air Pressure

Air pressure decreases as Air pressure decreases as altitude altitude increases. increases.

As air pressure decreases, so does As air pressure decreases, so does densitydensity. (see page 538). (see page 538)

Why is it hard to breathe at the top of a mountain?

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Part B: Weather FactorsPart B: Weather Factors

Chapter 17 Sections 1-5Chapter 17 Sections 1-5

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17:1 Energy in Earth’s atmosphere17:1 Energy in Earth’s atmosphere

Energy travels from the sun through the Energy travels from the sun through the vacuum of spacevacuum of space to the earth in to the earth in electromagnetic electromagnetic waves.waves.

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Most of the energy from the Most of the energy from the sun reaches the earth in the sun reaches the earth in the form of: form of: visible lightvisible light infrared radiation (heatinfrared radiation (heat) ) a small amount arrives as a small amount arrives as

ultraviolet radiationultraviolet radiation (see (see page 561)page 561)

Energy in Earth’s atmosphereEnergy in Earth’s atmosphere

Which color of visible light has the longest wavelength? 1111

Energy in the atmosphereEnergy in the atmosphere

Some sunlight is Some sunlight is absorbed or reflectedabsorbed or reflected by the atmosphere.by the atmosphere.

The rest passes The rest passes though the though the atmosphere to the atmosphere to the Earth’s surfaceEarth’s surface

See figure 2 page See figure 2 page 562562

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Energy at the Earth’s surfaceEnergy at the Earth’s surface

Some of the sun’s energy reaches the Some of the sun’s energy reaches the Earth’s surface and is reflected back into the Earth’s surface and is reflected back into the atmosphereatmosphere..

About half of the sun’s energy, however, is About half of the sun’s energy, however, is absorbed by the land and waterabsorbed by the land and water and changed and changed into heat.into heat.

When Earth’s surface is heated, it radiates When Earth’s surface is heated, it radiates most of the energy back into the atmosphere most of the energy back into the atmosphere as as infrared waves (heat)infrared waves (heat)

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This reflected infrared radiation is absorbed by This reflected infrared radiation is absorbed by Water VaporWater Vapor, , Carbon Dioxide, Methane, Carbon Dioxide, Methane, and and

other gases in the atmosphereother gases in the atmosphere These gases form a “These gases form a “blanketblanket” around the Earth ” around the Earth

that holds heat in the atmospherethat holds heat in the atmosphere The process by which gases hold heat in the air The process by which gases hold heat in the air

is called the is called the greenhouse effectgreenhouse effect

Energy at the Earth’s Energy at the Earth’s surfacesurface

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The way the greenhouse effect The way the greenhouse effect SHOULDSHOULD work: work: Green house effect is a Green house effect is a natural processnatural process that that

keeps the earth’s atmosphere at temperatures keeps the earth’s atmosphere at temperatures that are comfortable for most living things.that are comfortable for most living things.

The amount of energy absorbed is The amount of energy absorbed is balancedbalanced with with the amount of energy radiated back into space the amount of energy radiated back into space

The earth’s average The earth’s average temperatures remain fairly temperatures remain fairly constant.constant.


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Emissions from human Emissions from human activities, however are activities, however are altering this processaltering this process


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What human activities are What human activities are contributing to increased Green contributing to increased Green

house effect?house effect?

What can be done to stop it?What can be done to stop it?

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17:2 Thermal Energy and Temperature17:2 Thermal Energy and Temperature Temperature indicates the amount of Temperature indicates the amount of heatheat in in

the atmospherethe atmosphere Represents the Represents the speedspeed of the molecules of the molecules

Faster the molecules, Faster the molecules, higherhigher the temperature the temperature

Warmer air rises and cooler air sinks by a Warmer air rises and cooler air sinks by a process called process called convectionconvection currents currents

Measured with a Measured with a thermometerthermometer Standard unit is Standard unit is FahrenheitFahrenheit ( (°°F): 32F): 32°°F -212F -212°°FF SI Unit is SI Unit is CelsiusCelsius ( (°C): 0°C - 100°C°C): 0°C - 100°C

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Thermal energy from the Sun flows away Thermal energy from the Sun flows away from from hothot areas and towards areas and towards coolercooler areas. areas.

Thermal energy flows in Thermal energy flows in threethree ways: ways: Radiation, Conduction, & ConvectionRadiation, Conduction, & Convection

Heat Transfer Heat Transfer in the Atmospherein the Atmosphere

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Heat transferHeat transfer

Conduction Conduction – the transfer of – the transfer of heatheat through through an object, moving from one molecule to an object, moving from one molecule to another without the object another without the object movingmoving..

RadiationRadiation - heat energy is radiated or - heat energy is radiated or transmitted in the form of transmitted in the form of raysrays or or waveswaves of of particles.particles. Conduction at

surface of road

radiation

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Convection Convection – the movement of heat in – the movement of heat in liquidsliquids or or gasesgases..

This occurs when the particles nearest to the This occurs when the particles nearest to the heat source start to move heat source start to move fasterfaster causing the causing the matter to become less dense. matter to become less dense.

This cause an This cause an upwardupward movement through movement through less-heated matter. less-heated matter.

A A currentcurrent occurs because of the circular occurs because of the circular movementmovement

Heat Transfer in the Heat Transfer in the AtmosphereAtmosphere

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Convection is the process that drives Convection is the process that drives plateplate tectonics and creates global wind patternstectonics and creates global wind patterns..

Example: Example: Hot water (and air) rises, cools, and Hot water (and air) rises, cools, and then sinks back down.then sinks back down.

See figure 5 p. 569See figure 5 p. 569

Heat Transfer in the AtmosphereHeat Transfer in the Atmosphere

Convection currents from left to right:

In a boiling pot on a stove

In the oceans

Weather fronts in the atmosphere

Global Air Masses

Plate tectonics in the athenosphere

On the surface of the sun 2323

17:3 Winds17:3 Winds

Caused by differences in air pressureCaused by differences in air pressure Air moves from areas of high pressure to areas of low Air moves from areas of high pressure to areas of low

pressurepressure• Greater the difference in pressure, faster the wind movesGreater the difference in pressure, faster the wind moves

Wind Speed Wind Speed Measure of how Measure of how fastfast the air is moving the air is moving Measured with an Measured with an anemometeranemometer

Wind DirectionWind Direction Direction from which the wind is Direction from which the wind is coming,coming, NOT the direction it NOT the direction it

is blowingis blowing• Ex. North winds blow from N to SEx. North winds blow from N to S

Measure with a Measure with a WindWind VaneVane

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Convection Currents Convection Currents in the atmospherein the atmosphere

Heated air at the equator Heated air at the equator rises uprises up, and , and spreads north and south towards the poles. spreads north and south towards the poles.

It gradually cools, It gradually cools, sinks downsinks down in the polar in the polar regions, and then flows across the Earth regions, and then flows across the Earth surface back down to the equator. surface back down to the equator.

There it There it heats upheats up again and the convection again and the convection cycle is repeated. cycle is repeated.

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Convection Currents & Convection Currents & The Coriolis EffectThe Coriolis Effect

This is what would This is what would happen if the Earth did happen if the Earth did not rotate. not rotate.

Rotation adds another Rotation adds another twist to the story, twist to the story, because the because the Coriolis Coriolis EffectEffect makes the makes the currents veer off course.currents veer off course.

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Currents & Currents & The Coriolis EffectThe Coriolis Effect

The Coriolis effect The Coriolis effect is the shifting of the is the shifting of the winds and the surface currents of the winds and the surface currents of the ocean from their expected paths due to ocean from their expected paths due to the rotation of the earththe rotation of the earth. .

Because the Earth rotates toward the Because the Earth rotates toward the easteast, , the winds appear to curve toward the the winds appear to curve toward the rightright in the northern hemisphere and to the left in the northern hemisphere and to the left in the southern hemisphere.in the southern hemisphere.

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The Coriolis Effect & The Coriolis Effect & Global Wind BeltsGlobal Wind Belts

The Coriolis Effect and other The Coriolis Effect and other factors combine to produce a factors combine to produce a pattern of pattern of calm areascalm areas:: The doldrums andThe doldrums and The horse latitudes.The horse latitudes.

And major And major Global Wind BeltsGlobal Wind Belts around Earth. around Earth. TThe polar easterlies,he polar easterlies, The westerlies, and The westerlies, and The Trade windsThe Trade winds

Draw Color and Label Figure 11 page 575

Discuss and describe the three Discuss and describe the three major low altitude global wind beltsmajor low altitude global wind belts

Trade WindsTrade Winds Prevailing WesterliesPrevailing Westerlies Polar EasterliesPolar Easterlies See page 574-6See page 574-6

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Types of Global Winds- Types of Global Winds- Jet StreamsJet Streams

Jet streamsJet streams occur at occur at high altitudeshigh altitudes They are bands of strong winds near They are bands of strong winds near

the top of the troposphere at the the top of the troposphere at the northern and southern boundaries of northern and southern boundaries of the prevailing westerliesthe prevailing westerlies Race from west to eastRace from west to east They travel at speeds of 200 to They travel at speeds of 200 to

400 km/h400 km/h about 10 km above Earth’s surfaceabout 10 km above Earth’s surface They are hundreds of km wideThey are hundreds of km wide

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17:4 Water in the 17:4 Water in the AtmosphereAtmosphere

The The energy from the sunenergy from the sun creates the creates the heating that causes the convection currents heating that causes the convection currents of wind that drive the atmospheric of wind that drive the atmospheric circulation we’ve just discussed.circulation we’ve just discussed.

As the sun heats the land and oceans, the As the sun heats the land and oceans, the amount of amount of water in the atmospherewater in the atmosphere changes changes as well.as well.

This movement of water between the Earth This movement of water between the Earth and the atmosphere is the and the atmosphere is the water cycle. water cycle.

See page 579See page 579 3131

HumidityHumidity

HumidityHumidity is a measure of the amount of is a measure of the amount of water vapor in the air.water vapor in the air.

Air’s ability to hold water vapor depends Air’s ability to hold water vapor depends on its on its temperaturetemperature..

Warm air can hold Warm air can hold moremore water vapor than water vapor than cold air.cold air.

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Relative HumidityRelative Humidity Relative humidityRelative humidity is the is the percentagepercentage of of

water vapor that is actually in the air water vapor that is actually in the air compared to the maximumcompared to the maximum amount of amount of water vapor that the air can hold.water vapor that the air can hold.

It is measured with a It is measured with a psychrometerpsychrometer Give an example of relative humidityGive an example of relative humidity

See page 579-560See page 579-560

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Dew pointDew point

Dew is the water vapor that has Dew is the water vapor that has condensedcondensed on a surface into a liquid on a surface into a liquid Depends on two factorsDepends on two factors

• Amount of Amount of water vaporwater vapor in the air in the air• Temperature near the Temperature near the surfacesurface

Forms when temperature at the surface falls to Forms when temperature at the surface falls to a point where the air near the surface is a point where the air near the surface is saturated saturated causing more water vapor to causing more water vapor to condense than evaporatecondense than evaporate

Dew point is the Dew point is the temperaturetemperature at which at which water vapor condenses water vapor condenses

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17:5 Precipitation 17:5 Precipitation Water evaporates and collects Water evaporates and collects

on on dust or gas dust or gas particles to create particles to create cloudsclouds..

When the droplets grow heavy When the droplets grow heavy enough they will fall back to enough they will fall back to earth.earth.

PrecipitationPrecipitation is any form of water is any form of water that falls from clouds and that falls from clouds and reaches earth’s surfacereaches earth’s surface

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PrecipitationPrecipitation

Water in any form Water in any form fallingfalling from clouds from clouds RainRain: liquid as it falls: liquid as it falls SnowSnow: frozen in clouds and then falls through : frozen in clouds and then falls through

the cold atmospherethe cold atmosphere SleetSleet: melts and then re-freezes as it falls : melts and then re-freezes as it falls

through the atmospherethrough the atmosphere HailHail: only forms in thunderstorms from strong : only forms in thunderstorms from strong

winds tossing ice crystals up and down high winds tossing ice crystals up and down high in the atmospherein the atmosphere

Measured with a Measured with a rain gaugerain gauge3636


Part C: Weather PatternsPart C: Weather Patterns

Chapter 18 Sections 1-3Chapter 18 Sections 1-3

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Air MassesAir Masses Large bodies of air that have a certain Large bodies of air that have a certain temperature temperature

and amount of moistureand amount of moisture 4 types4 types

MaritimeMaritime tropical: warm moist air that develops tropical: warm moist air that develops over the ocean near the equatorover the ocean near the equator

Maritime Maritime polarpolar: cool moist air that develops over : cool moist air that develops over the ocean north of the United Statesthe ocean north of the United States

ContinentalContinental tropical: hot dry air that forms over tropical: hot dry air that forms over Mexico and moves North in the summerMexico and moves North in the summer

Continental Continental polarpolar: Cold dry air that moves into : Cold dry air that moves into the United State from Canadathe United State from Canada

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Air Masses That Affect The United StatesAir Masses That Affect The United States

In the continental United States, air masses are commonly moved by the prevailing Westerlies and Jet Streams.

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Boundaries become FrontsBoundaries become Fronts

As the huge air masses move across the As the huge air masses move across the land and oceans they land and oceans they collidecollide with each with each other.other.

Because of differences in humidity, Because of differences in humidity, density, and temperature- the masses density, and temperature- the masses do do not easily mix.not easily mix.

The boundary where two air masses meet The boundary where two air masses meet becomes a becomes a frontfront..

StormsStorms and changeable weather often and changeable weather often develop along these fronts.develop along these fronts. 4040

Weather Fronts:Weather Fronts: ColdCold front: cold air mass pushes under warm air front: cold air mass pushes under warm air

massmass Causes short violent Causes short violent stormsstorms followed by fair followed by fair

cooler weathercooler weather WarmWarm front: warm air mass slides up over a cold front: warm air mass slides up over a cold

air massair mass Causes Causes widespreadwidespread precipitation followed by precipitation followed by

warmer, humid weatherwarmer, humid weather

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Cold and Warm FrontsCold and Warm Fronts

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Cold Front- cold air mass overtakes a warm air mass

Warm Front- warm air mass overtakes a cold air mass

Weather FrontsWeather Fronts StationaryStationary front: warm and cold air front: warm and cold air

mass meet, but neither advancemass meet, but neither advance Causes many days of Causes many days of continuouscontinuous

precipitationprecipitation OccludedOccluded front: a warm air mass is front: a warm air mass is

caught between two cold air massescaught between two cold air masses Usually produces strong winds with Usually produces strong winds with

large amounts of rain or snow with large amounts of rain or snow with much cooler temperaturesmuch cooler temperatures

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How do high and low pressure areas form?How do high and low pressure areas form?

What type of weather associated with each?What type of weather associated with each?

See page 602See page 602

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18:2 Stormy Weather18:2 Stormy Weather

Storms are natural disturbances in the Storms are natural disturbances in the atmosphere that involve atmosphere that involve low air pressure, clouds, low air pressure, clouds, precipitation, and strong windsprecipitation, and strong winds ThunderstormsThunderstorms: brief, intense storm caused by rapidly : brief, intense storm caused by rapidly

rising clouds that can produce lightening, thunder and rising clouds that can produce lightening, thunder and hail hail

TornadosTornados: violent, whirling winds produced by : violent, whirling winds produced by thunderstorm clouds with extremely low air pressurethunderstorm clouds with extremely low air pressure

HurricanesHurricanes: huge, rotating storm that forms over the : huge, rotating storm that forms over the warm ocean waters due to extreme low pressureswarm ocean waters due to extreme low pressures

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Stormy Weather- Stormy Weather- ThunderstormsThunderstorms

One of the most common examples of foul One of the most common examples of foul weather is the weather is the thunderstormthunderstorm

Thunderstorms are often accompanied by Thunderstorms are often accompanied by towering cumulonimbus clouds called towering cumulonimbus clouds called thunderheadsthunderheads..

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ThunderheadsThunderheads are formed when warm, moist are formed when warm, moist air rises, often reaching ten miles or more in the air rises, often reaching ten miles or more in the air.air.

Thunderheads produce two well known features Thunderheads produce two well known features of stormy weather- of stormy weather- lightning and thunderlightning and thunder. .


Lightning Lightning is an electrical spark caused by is an electrical spark caused by friction inside the thunderhead.friction inside the thunderhead.– As the clouds grow, raindrops scrape against As the clouds grow, raindrops scrape against

each other, and each other, and frictionfriction is produced is produced– This friction builds up into a negative This friction builds up into a negative static static

electrical chargeelectrical charge..– These negative charges emit a These negative charges emit a sparkspark that that

can jump between clouds or between the can jump between clouds or between the clouds and the ground clouds and the ground


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Lightning instantly Lightning instantly heatsheats the the air around its path to up to air around its path to up to five times the surface of the five times the surface of the sun.sun.

The The collisioncollision between the between the superheated air near the superheated air near the lightning spark and the lightning spark and the cooler air around it produces cooler air around it produces the sound we know as the sound we know as thunderthunder

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A A tornadotornado is a very small area of very is a very small area of very violent weather.violent weather.

In severe thunderstorms, winds at In severe thunderstorms, winds at different heights blow in different directions different heights blow in different directions and at different speeds.and at different speeds.

This difference in wind direction and This difference in wind direction and speed, called speed, called wind shear,wind shear, creates a creates a rotating column parallel to the ground.rotating column parallel to the ground.

A thunderstorm’s updraft can A thunderstorm’s updraft can tilttilt the the rotating column upward creating a rotating column upward creating a funnel funnel cloudcloud..

Stormy Weather- TornadoesStormy Weather- Tornadoes

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Most tornadoes are not very big, ranging Most tornadoes are not very big, ranging in size from only in size from only 150 to 600 feet150 to 600 feet in in diameter.diameter.

Winds in a tornado can spin at up to Winds in a tornado can spin at up to 300 300 miles per hourmiles per hour


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Most tornadoes in the Most tornadoes in the United States occur in the United States occur in the Midwest, in an are called Midwest, in an are called Tornado AlleyTornado Alley

This includes the states of This includes the states of Texas, Oklahoma, Kansas, Texas, Oklahoma, Kansas, Missouri, Nebraska, Iowa, Missouri, Nebraska, Iowa, Illinois, and IndianaIllinois, and Indiana

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Stormy Weather- HurricanesStormy Weather- Hurricanes

HurricanesHurricanes, unlike , unlike tornadoes, are huge tornadoes, are huge storms that can have a storms that can have a diameter of diameter of hundreds of hundreds of milesmiles

The winds in a hurricane The winds in a hurricane are slower, ranging from are slower, ranging from aboutabout 75 to over 150 75 to over 150 miles per hour.miles per hour.

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Hurricane KatrinaHurricane Katrina

Click on hurricane above to follow a link to the evolution of a hurricane

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Causes of HurricanesCauses of Hurricanes

Causes of hurricanes: characterized by a Causes of hurricanes: characterized by a large low-pressure center and numerous large low-pressure center and numerous thunderstorms that produce strong winds thunderstorms that produce strong winds and heavy rain. and heavy rain. Tropical cyclones feed on heat released when Tropical cyclones feed on heat released when

moist air rises due to extreme low pressure moist air rises due to extreme low pressure resulting in condensation of water vapor resulting in condensation of water vapor contained in the moist air contained in the moist air

Follow the Links marked in green

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Predicting the Path ofPredicting the Path ofHurricanesHurricanes

Hurricane season: Hurricane season: June to NovemberJune to November 100’s of kilometers wide & last for several days100’s of kilometers wide & last for several days Hurricanes form over Hurricanes form over warm waterwarm water , so they , so they

bring with them much rain, high winds, and bring with them much rain, high winds, and giant waves.giant waves.

Hurricanes begin as Hurricanes begin as tropical depressionstropical depressions, or , or low- pressure zones over warm, tropical waters.low- pressure zones over warm, tropical waters.

If the winds of the tropical depression reach If the winds of the tropical depression reach about about 40 miles per hour40 miles per hour, the depression , the depression becomes a becomes a tropical stormtropical storm..

If the outer winds reach about If the outer winds reach about 75 miles per 75 miles per hour,hour, the tropical storm becomes a the tropical storm becomes a hurricanehurricane..

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Categories of HurricanesCategories of Hurricanes

Category oneCategory one Maximum sustained wind speed : Maximum sustained wind speed : 74-95 74-95 mphmph Damage category: Damage category: minimalminimal Approximate storm surge: 3-5 feetApproximate storm surge: 3-5 feet Examples: Hurricane Lilli (2002) LouisianaExamples: Hurricane Lilli (2002) Louisiana Hurricane Gaston (2004) South Carolina Hurricane Gaston (2004) South Carolina

Click on title to see typical damage of each category

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Category twoCategory two Maximum sustained wind speed : Maximum sustained wind speed : 96-11096-110

mphmph Damage category: Damage category: moderatemoderate Approximate storm surge: 6-8 feetApproximate storm surge: 6-8 feet Example: Hurricane Isabel (2003) North Example: Hurricane Isabel (2003) North

Carolina Carolina 5959


Category threeCategory three Maximum sustained wind speed : 111-Maximum sustained wind speed : 111-

130 mph130 mph Damage category: ExtensiveDamage category: Extensive Approximate storm surge: 9-12 feetApproximate storm surge: 9-12 feet Examples: Examples: Hurricane Katrina (2005)Hurricane Katrina (2005)

Louisiana, Hurricane Jeanne (2004) Louisiana, Hurricane Jeanne (2004) Florida, Hurricane Ivan (2004) Alabama Florida, Hurricane Ivan (2004) Alabama

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Category FourCategory Four Maximum sustained wind speed : Maximum sustained wind speed : 131-131-

155 mph155 mph Damage category: Damage category: ExtremeExtreme Approximate storm surge: 13-18 feetApproximate storm surge: 13-18 feet Examples: Hurricane Charley (2004) Examples: Hurricane Charley (2004)

Florida, Hurricane Iniki (1992) Hawaii, Florida, Hurricane Iniki (1992) Hawaii, The Galveston Hurricane (1900) TexasThe Galveston Hurricane (1900) Texas

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Categories of HurricanesCategories of Hurricanes Category FiveCategory Five

Maximum sustained wind speed : Maximum sustained wind speed : above 155 mphabove 155 mph Damage category: Damage category: catastrophiccatastrophic Approximate storm surge: more than 18 feetApproximate storm surge: more than 18 feet Examples: only three Category 5 hurricanes have Examples: only three Category 5 hurricanes have

struck the U.S. since records began. They are: struck the U.S. since records began. They are: The Labor Day Hurricane (1935) Florida Keys, The Labor Day Hurricane (1935) Florida Keys, Hurricane Camille (1969) near mouth of Mississippi Hurricane Camille (1969) near mouth of Mississippi River, and Hurricane Andrew (1992) in FloridaRiver, and Hurricane Andrew (1992) in Florida

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HurricanesHurricanes

Complete the “Tracking a Hurricane” Complete the “Tracking a Hurricane” Activity on page 614 & 615 of your textActivity on page 614 & 615 of your text

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Weather ForecastingWeather Forecasting

The Sun, water, and air all work together to The Sun, water, and air all work together to produce weather.produce weather.

People who study these factors and predict People who study these factors and predict the weather are called the weather are called meteorologists.meteorologists.

A weather A weather forecastforecast is a prediction of is a prediction of present conditions based on observations present conditions based on observations and dataand data

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Weather Maps: Weather Maps: Predicting the weatherPredicting the weather

Satellite map: allow meteorologists to Satellite map: allow meteorologists to monitor weather on the global scalemonitor weather on the global scale

Radar Map: uses electromagnetic Radar Map: uses electromagnetic waves to monitor velocity and altitudewaves to monitor velocity and altitude

Weather Map: shows current weather or Weather Map: shows current weather or the predictions about the weather after the predictions about the weather after analyzing the dataanalyzing the data 6565


Meteorologists take measurements of Meteorologists take measurements of temperature, air pressure, winds, humidity & temperature, air pressure, winds, humidity & precipitationprecipitation

To gather data & create weather maps, they To gather data & create weather maps, they useuse– ComputersComputers– Weather satellitesWeather satellites– Doppler radarDoppler radar– Instruments attached to special balloonsInstruments attached to special balloons

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Meteorologists cannot always predict the Meteorologists cannot always predict the weather accurately because weather accurately because conditions can conditions can change rapidlychange rapidly

The National Weather Service depends on The National Weather Service depends on two sources for its informationtwo sources for its information– Data collected from the Data collected from the upper atmosphereupper atmosphere – And data collected from And data collected from Earth's surfaceEarth's surface

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Meteorologists use satellites, instruments Meteorologists use satellites, instruments attached to weather balloons, and radar to attached to weather balloons, and radar to describe conditions in the upper atmosphere describe conditions in the upper atmosphere

Data from Earth's surface is recorded on a map Data from Earth's surface is recorded on a map using a combination of symbols forming a using a combination of symbols forming a Weather service mapWeather service map– A A weather service mapweather service map shows weather conditions shows weather conditions

at a specific location on Earth's surfaceat a specific location on Earth's surface

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This chart is an This chart is an example of the example of the types of types of information information shown on a shown on a weather service weather service mapmap

Complete the Complete the “Interpreting “Interpreting Data” questions Data” questions on page 620 on page 620

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In addition to weather service maps, In addition to weather service maps, weather maps have lines that connect weather maps have lines that connect points of equal temperature or points of equal temperature or pressure.pressure.– Lines that connect points of equal Lines that connect points of equal

temperature are called temperature are called isothermsisotherms– An An isobarisobar is a line that connects is a line that connects

points of equal pressurepoints of equal pressure

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IsobarsIsobars

You can tell how fast You can tell how fast wind wind is blowing in an area is blowing in an area by noting how closely isobars are spacedby noting how closely isobars are spaced– Isobars close together indicate large pressure Isobars close together indicate large pressure

difference over a small areadifference over a small area– This difference causes This difference causes strong windsstrong winds– Isobars spread further apart indicate less pressure Isobars spread further apart indicate less pressure

difference and gentler winds difference and gentler winds

Isobars also indicate the locations of Isobars also indicate the locations of high and high and lowlow pressure areas pressure areas 7171

Discussion QuestionDiscussion Question

How do isobars indicate wind speed?How do isobars indicate wind speed?– Isobars close together indicate large Isobars close together indicate large

pressure difference over a small pressure difference over a small area which creates strong windsarea which creates strong winds

– Isobars spread further apart indicate Isobars spread further apart indicate less pressure difference and gentler less pressure difference and gentler winds winds

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Weather Weather ForecastingForecasting

On a weather map, On a weather map, pressure areaspressure areas are drawn are drawn as circles with the word high or low (of just the as circles with the word high or low (of just the letter H or L) in the middle of the circle.letter H or L) in the middle of the circle.

Fronts are drawn as Fronts are drawn as lines and symbolslines and symbolsAs you watch weather forecasts, notice the As you watch weather forecasts, notice the

weather patterns move from weather patterns move from west to east.west to east.– This is a This is a patternpattern that meteorologists depend on to that meteorologists depend on to

forecast the weather.forecast the weather.7373

DiscussionDiscussionWhat type of front is between the two low What type of front is between the two low

pressure areas?pressure areas?– Stationary frontStationary front

What type is above Northern California?What type is above Northern California?– Occluded FrontOccluded Front

How would the wind speed between the isobars How would the wind speed between the isobars with the red arrows compare to the isobars with with the red arrows compare to the isobars with the blue arrows? the blue arrows? – Winds are stronger between the red arrows, Winds are stronger between the red arrows,

gentler between the blue arrowsgentler between the blue arrows 7474

Complete the “Reading a Weather Complete the “Reading a Weather Map” exercise page 623.Map” exercise page 623.

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climate and weather state correlation 4c, 4h, 4d 1

Documents

suns energy

air pressure decreases

column of air

air pressureair pressure

earths surfacesome

pressurethe atmosphere

density density

earths average temperatures