Earth’s Earth’s AtmosphereAtmosphere

Chapter 15

Characteristics of the Characteristics of the AtmosphereAtmosphere

• You should have all of your notes from 15.1 on this graphic organizer.

Troposphere

Stratosphere

Mesosphere

Thermosphere

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AurorasAuroras• Northern and Southern

Lights …WHY??? • Nitrogen and Oxygen

absorb energy from the sun

• Increase in temperature• Electrically charge gas

particles = ions• The ions radiate energy

as shimmering lights

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Atmospheric HeatingAtmospheric Heating

• Earth and the Atmosphere are warmed by energy from the sun!

• Heat moves from areas of warmth to areas of cold

Three ways heat can be transferred:1. Radiation2. Conduction3. Convection

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Radiation

• Transfers energy through

infrared waves (sun or fire)

• Can move through EMPTY space

• No direct contact between heat source and an object.

• Example: bonfire warming your face

Heat given off from a light bulb is also a form of radiation…

Heat from a bonfire is an example of radiation…

Conduction

• Transfers heat through DIRECT CONTACT of particles (solid to solid)

• Example: bare feet on hot pavement

A spoon heating up in a pot of soup!

The pan gets HOT because it is touching the HOT burner on the stove!

Convection• Transfer of heat through the movement of

FLUIDS and GASES

• Example: soup heating inside a pot

• Movement is created by differences in DENSITY– Hot things = less dense = rise to the top– Cold things = more dense = fall to the bottom

ConvectionExample: Lava Lamp

Hot!Hot!= less dense = less dense

= rise to the = rise to the toptop

Cools off!Cools off!= more dense = more dense = fall to the = fall to the bottombottom

Review… Via Video Review… Via Video

Energy in the Atmosphere

Comes from th

e sun!

Comes from th

e sun!

Electromagnetic WavesElectromagnetic Waves• Electromagnetic waves are energy from the sun

that can travel through space

• Remember….

• The transfer of energy by electromagnetic waves is called RADIATION.

Electromagnetic Spectrum

The electromagnetic spectrum organizes the radiation from the sun from the longest wavelength to the

shortest wavelength.

The Greenhouse Effect

• Earth’s atmosphere gases act as a “blanket” and hold in the heat from the infrared radiation.

• The greenhouse effect helps Earth maintain a comfortable livable temperature, even at night.

Heat Transfer (Review!!)

1. Radiation – Heat that you feel from a heat source. EX: sun or fire (infrared radiation)

2. Conduction – Direct transfer of heat from one object touching another object

3. Convection – Transfer of heat by the movement of a fluid or air (convection current)

Radiation, conduction, and convection work together to heat the troposphere.

Heat Transfer (Review examples!!)AIR COOLS OFF

(Drops back Down)

Which type of heat transfer?

1. Your feet get hot when walking barefoot across hot pavement.

2. You can feel the heat from the hot iron without touching it.

3. In winter, the second floor of your house is warmer than the first floor.

4. You are lying on the beach and the sun makes your skin tingle.

5. You burn your finger when you accidentally touch the hot stove.

Which type of heat transfer?1. Your feet get hot when walking barefoot

across hot pavement. Conduction

2. You can feel the heat from the hot iron without touching it. Radiation

3. In winter, the second floor of your house is warmer than the first floor. Convection

4. You are lying on the beach and the sun makes your skin tingle. Radiation

5. You burn your finger when you accidentally touch the hot stove. Conduction

Air in the atmosphere acts as a fluid (water vapor). The sun's radiation strikes the ground = warming the rocks/ground. As the ground’s temperature rises due to conduction, heat energy is released into the atmosphere, forming a “bubble” of air which is warmer than the surrounding air. This “bubble” of air rises into the atmosphere. As it rises, the air in the “bubble” cools and becomes more dense. The movement of the air creates wind. Convection currents are responsible for many weather patterns in the troposphere.

Hot Air Rises…But how does the ground get

hotter??? …It is farther from the sun!

ConvectionConvectionCurrents!Currents!

Winds 15.3Winds 15.3

What causes winds?What causes winds?

• Differences in air pressureDifferences in air pressure

• More of a difference in pressure = faster windsMore of a difference in pressure = faster winds

Lots of differenceLots of difference

Air Rises @ EquatorAir Rises @ EquatorAir Sinks @ PolesAir Sinks @ Poles

• You know… – Warm air rises = less dense– Cool air sinks = more dense

• Now understand…Now understand…–Warm air = less dense Warm air = less dense

= low pressure= low pressure–Cool air = more dense Cool air = more dense

= high pressure= high pressure

Info… via Video… Info… via Video…

Global WindsGlobal Winds• Created by unequal heating of Earth’s surface.Created by unequal heating of Earth’s surface.

Global Winds… Global Winds… cont…cont…

• The movement of air The movement of air between the equator between the equator and the poles and the poles produces global produces global winds.winds.

• Coriolis effectCoriolis effect produces produces patterns of air circulation patterns of air circulation called called global windsglobal winds..

Global Wind BeltsGlobal Wind Belts• Major global wind systems:Major global wind systems:

• Polar easterlies, westerlies, and trade winds.Polar easterlies, westerlies, and trade winds.

DoldrumsDoldrums• Where the trade winds meet around the equatorWhere the trade winds meet around the equator

• Very little wind because the warm air rising = Very little wind because the warm air rising = low pressurelow pressure

Horse LatitudesHorse Latitudes• High pressure areas… 30High pressure areas… 3000N and 30N and 3000SS

• Very week windsVery week winds

Jet StreamsJet Streams

• Bands of high speed windsBands of high speed winds

• Upper troposphere and Upper troposphere and lower stratospherelower stratosphere

• Blow from west to east at Blow from west to east at speeds of 200-400 km/hr.speeds of 200-400 km/hr.

• Help airplanes save fuel Help airplanes save fuel and time when traveling and time when traveling east.east.

Local WindsLocal WindsHave you ever flown a kite at the beach on a hot summer day? Even if there is

no wind inland, there may be a cool breeze blowing in from the water toward the beach. This breeze is an example of local winds!

• Local winds are winds that blow over short Local winds are winds that blow over short distances.distances.

• They are caused by unequal heating of Earth’s They are caused by unequal heating of Earth’s surface within a small area.surface within a small area.

• Types: Types: – sea breezes sea breezes and and land breezesland breezes– Mountain breeze and valley breezeMountain breeze and valley breeze

Sea Breeze (Morning)Sea Breeze (Morning)

Land heats up faster than water. Hot air over land rises (Low Pressure), cool air over water falls (High Pressure). Winds move from the water (High Pressure) to the land (Low Pressure).

Land Breeze (Evening)Land Breeze (Evening)

Land cools off faster than water. Cool air over land falls (High Pressure), warm air over water rises (Low Pressure). Winds move from the land (High Pressure) to the water (Low Pressure).

Valley Breeze (Day)Valley Breeze (Day)

During the day the sun warms the air slopes, creating a valley breeze…

at nightfall, the air along the mountain slopes cools…

Mountain Breeze (Night)Mountain Breeze (Night)

This cool air moves down the slopes into the valley, producing a mountain breeze!

Measuring WindMeasuring Wind

• Winds are described by their direction Winds are described by their direction and speed.and speed.

• Wind direction is determined with a Wind direction is determined with a wind vane – points in the direction the wind vane – points in the direction the wind is moving!wind is moving!

• Wind speed is measured with an Wind speed is measured with an anemometer.anemometer.

• The increased cooling that a wind can The increased cooling that a wind can cause is called the wind chill factor.cause is called the wind chill factor.

Anemometer – The cups catch the wind, turning faster when the wind blows faster.

Wind Vane