EARTH SCIENCE

ES02 - Atmosphere

Bell Ringer

List and explain how the atmosphere might

affect the different spheres (hydrosphere,

geosphere, & biosphere) on Earth.

Bell Ringer

Does pollution caused by other countries

affect us here in the US? Explain your

answer.

Bell Ringer

Using all of the information you have

learned in this unit, briefly explain how

weather occurs in our atmosphere. Use the

words humidity, clouds, precipitation,

thunderstorm, wind, and air mass. In your

description you cannot use these words

with commas or the word and.

Composition of the Atmosphere

Atmosphere

Weather

refers to the

state of the

atmosphere

at any given

time and

place.

Composition of the Atmosphere

Atmosphere

Climate is based on observations of

weather that have been collected over

many years.

Composition of the Atmosphere

Atmosphere

Major Components of Air • Air is a mixture of different gases and particles,

each with its own physical properties.

- Nitrogen – 78%

- Oxygen – 20%

- Carbon Dioxide

– >1%

- Water Vapor – 1%

Composition of the Atmosphere

Atmosphere

Important Components

• Ozone is a form of oxygen that combines three

oxygen atoms into each molecule (O3).

Ozone & CFC’s

Composition of the Atmosphere

Atmosphere

Important Components

• Water vapor is the source of all clouds and

precipitation.

• Water vapor

absorbs heat

given off by

Earth. It also

absorbs some

solar energy.

Height & Structure of the Atmosphere

Atmosphere

The atmosphere

rapidly thins as

you travel away

from Earth until

there are too few

gas molecules to

detect.

Atmospheric Pressure vs. Altitude

Height and Structure of the

Atmosphere

17.1 Atmosphere Characteristics

Temperature Changes • The atmosphere can be divided vertically into four

layers based on temperature.

• The troposphere is the bottom layer of the

atmosphere where temperature decreases with an

increase in altitude. This is where all weather takes

place. • The stratosphere is the layer of the atmosphere

where temperature remains constant to a height

of about 20 kilometers. It then begins a gradual

increase until the stratopause.

Snowy Mountaintops Contrast with

Warmer Snow-Free Lowlands

Height and Structure of the

Atmosphere

17.1 Atmosphere Characteristics

Temperature Changes • The mesosphere is the layer of the atmosphere

immediately above the stratosphere and is

characterized by decreasing temperatures with

height.

• The thermosphere is the region of the

atmosphere immediately above the mesosphere

and is characterized by increasing temperatures

due to the absorption of very short-wave solar

energy by oxygen.

Thermal Structure of the Atmosphere

Earth-Sun Relationships

Atmosphere

Solstices and Equinoxes

• The summer

solstice occurs on

June 21 or 22 and

is the first day of

summer.

Earth-Sun Relationships

Atmosphere

Solstices and Equinoxes

• The winter solstice

occurs on

December 21 or

22 and is the first

day of winter.

Earth-Sun Relationships

Atmosphere

Solstices and Equinoxes

• The autumnal

equinox occurs

on September

22 or 23.

Earth-Sun Relationships

Atmosphere

Solstices and Equinoxes

• The spring

equinox occurs

on March 21 or

22.

Bell Ringer

Describe the concept of heat in your own

words.

Energy Transfer as Heat

Atmosphere

Heat is the energy transferred from one

object to another because of a difference in

the objects’ temperature.

Energy Transfer as Heat

Atmosphere

Three mechanisms of energy transfer as

heat are conduction, convection, and

radiation.

• Conduction is the

transfer of heat

through matter by

molecular activity.

Conduction

Energy Transfer as Heat

Atmosphere

• Convection is

the transfer of

heat by mass

movement or

circulation

within a

substance.

Convection

Energy Transfer as Heat

Atmosphere

Radiation

• Radiation is the

transfer of energy

(heat) through

space by

electromagnetic

waves that travel

out in all

directions.

What Happens to Solar Radiation?

Atmosphere

Absorption

• The greenhouse

effect is the

heating of

Earth’s surface &

atmosphere from

solar radiation

being absorbed

by the

atmosphere.

What Happens to Solar Radiation?

Atmosphere

Absorption

• Two main greenhouse gases are water vapor &

carbon dioxide.

The Greenhouse Effect

Solar Radiation

Why Temperatures Vary

Atmosphere

Factors other than latitude that exert a

strong influence on temperature include

heating of land and water, altitude,

geographic position, cloud cover, and

ocean currents.

Why Temperatures Vary

Atmosphere

Land and Water

Why Temperatures Vary

Atmosphere

Land and Water • Land heats faster

and to higher

temperatures than

water.

• Land also cools

faster and to lower

temperatures than

water.

Mean Monthly Temperatures

for Vancouver and Winnipeg

Why Temperatures Vary

Atmosphere

Geographic Position

• The geographic setting can greatly influence

temperatures experienced at a specific location.

Mean Monthly Temperatures for

Eureka and New York City

Why Temperatures Vary

Atmosphere

Altitude

• The altitude can greatly influence temperatures

experienced at a specific location.

Mean Monthly Temperatures for

Guayaquil and Quito

Why Temperatures Vary

Atmosphere

Cloud Cover and Albedo • Albedo is the fraction of total radiation that is

reflected by any surface.

• Many clouds have a high albedo and therefore

reflect back to space a significant portion of the

sunlight that strikes them.

World Distribution of Temperature

Atmosphere

Isotherms are lines on a weather map that

connect points where the temperature is

the same.

Bell Ringer

How does living in a coastal region affect

our daily temperatures?

Bell Ringer

In your own words, explain what humidity is

and why it’s important to understanding the

weather.

Water’s Changes of State

Atmosphere

Precipitation is any form of water that falls

from a cloud.

When it comes to understanding

atmospheric processes, water vapor is the

most important gas in the atmosphere.

Water’s Changes of State

Atmosphere

Solid to Liquid • The process of changing state, such as melting

ice, requires that energy be transferred in the form

of heat.

Liquid to Gas

• Evaporation is the process of changing a liquid to

a gas.

Water’s Changes of State

Atmosphere

Liquid to Solid

Gas to Liquid • Condensation is the process where a gas, like

water vapor, changes to a liquid, like water.

• The process of changing state, such as freezing

water, requires that energy be transferred in the

form of heat.

Water’s Changes of State

Atmosphere

Solid to Gas

• Sublimation is the conversion of a solid directly

to a gas without passing through the liquid state.

• Deposition is the conversion of a vapor directly

to a solid.

Gas to Solid

Water’s Changes of State

Atmosphere

Humidity

Atmosphere

Humidity is a

general term for

the amount of

water vapor in

air.

Humidity

Atmosphere

• Air is saturated when it contains the maximum

amount of water vapor that it can hold at any

given temperature and pressure.

• When saturated, warm air contains more water

vapor than cold saturated air.

Saturation

Humidity

Atmosphere

• Relative humidity is a ratio of the air’s actual

water-vapor content compared with the amount

of water vapor air can hold at that temperature.

Relative Humidity

Humidity

Atmosphere

• Dew point is the temperature to which a parcel of air

would need to be cooled to reach saturation.

Dew Point

Humidity

Atmosphere

Measuring Humidity

• A hygrometer is an instrument to measure relative

humidity.

• A psychrometer is a hygrometer

with dry- and wet-bulb

thermometers. Evaporation of

water from the wet bulb makes air

temperature appear lower than

the dry bulb’s measurement. The

two temperatures are compared

to determine the relative humidity.

Bell Ringer

Based off of what you know about the

atmosphere and what you learned in your

humidity lab, infer how clouds and

precipitation are created.

Processes That Lift Air

Atmosphere

• Orographic lifting occurs when mountains act as

barriers to the flow of air, forcing the air to

ascend.

Orographic Lifting

Processes That Lift Air

Atmosphere

Frontal Wedging

• A front is the boundary between two adjoining air

masses having contrasting characteristics.

Condensation

Atmosphere

For any form

of

condensation

to occur, the

air must be

saturated.

Condensation

Atmosphere

• Generally, there must be a surface for water

vapor to condense on.

Types of Surfaces

Condensation

Atmosphere

Types of Surfaces

• Condensation nuclei are tiny bits of matter that

serve as surfaces on which water vapor

condenses when condensation occurs in the air.

Types of Clouds

Atmosphere

Clouds are classified on the basis of their

form and height.

• Cirrus are

clouds that are

high, white, and

thin.

Types of Clouds

Atmosphere

• Cumulus are mid-level clouds that consist of

rounded individual cloud masses.

Types of Clouds

Atmosphere

• Stratus are low clouds best described as sheets

or layers that cover much or all of the sky.

Cloud Classification

Types of Clouds

Atmosphere

• Nimbostratus clouds are the main precipitation

makers.

Cloud Classification

Types of Clouds

Atmosphere

Clouds of Vertical Development

• Cumulonimbus do not fit into any one of the

three height categories mentioned. These clouds

create thunderstorms.

Cloud Classification

Fog

Atmosphere

Fog is defined as a cloud with its base at or

very near the ground.

How Precipitation Forms

Atmosphere

For precipitation to form, cloud droplets

must grow in volume by roughly one million

times.

How Precipitation Forms

Atmosphere

Warm Cloud Precipitation

• The collision-

coalescence process

is a theory of raindrop

formation in warm

clouds (above 0oC)

where large cloud

droplets collide and

join together with

smaller droplets to

form a raindrop.

Forms of Precipitation

Atmosphere

The type of precipitation that reaches

Earth’s surface depends on the temperature

lower few km’s of the atmosphere.

Atmosphere

Forms of Precipitation

Atmosphere

• In meteorology, the term ―rain” means drops of

water that fall from a cloud and have a diameter

of at least 0.5 mm.

Rain

Forms of Precipitation

Atmosphere

Snow

• At very low temperatures (when the moisture

content of air is low) light fluffy snow made up

of individual six-sided ice crystals forms.

Forms of Precipitation

Atmosphere

• Sleet is the fall of clear-to-translucent ice.

Sleet

Forms of Precipitation

Atmosphere

Hail

• Hailstones

begin as

small ice

pellets that

grow as they

fall through a

cumulonimbu

s cloud.

Bell Ringer

Describe some possible causes for wind,

then infer what the purpose of wind is on

Earth.

Air Pressure Defined

Atmosphere

Air pressure is the pressure exerted by the

weight of air.

Air pressure is

exerted in all

directions— down,

up, and sideways.

Measuring Air Pressure

Atmosphere

A barometer is a device used for measuring

air pressure.

Factors Affecting Wind

Atmosphere

Solar radiation is the ultimate energy

source for most wind.

The unequal heating of Earth’s surface

generates pressure differences.

Factors Affecting Wind

Atmosphere

Wind is the result of horizontal differences

in air pressure. Air flows from areas of

higher pressure to areas of lower pressure.

Factors Affecting Wind

Atmosphere

Coriolis Effect

• The Coriolis effect

describes how Earth’s

rotation affects moving

objects.

• In the Northern

Hemisphere, all free-

moving objects/fluids are

deflected to the right of

their path.

Highs and Lows

Atmosphere

Cyclonic Winds

• In cyclones, the pressure decreases from the

outer isobars toward the center.

• Cyclones are centers of low pressure.

• Winds blow counterclockwise; net flow is inward.

Highs and Lows

Atmosphere

Anticyclonic Winds

• In anticyclones, the pressure increases from the

outer isobars toward the center.

• Anticyclones are centers of high pressure.

• Winds blow clockwise; net flow is outward.

Cyclonic and Anticyclonic Winds

Highs and Lows

Atmosphere

Weather and Air Pressure

• Rising air is associated with cloud formation and

precipitation, whereas sinking air produces clear

skies.

Highs and Lows

Atmosphere

Weather Forecasting

• Weather reports emphasize the locations and

possible paths of cyclones and anticyclones.

• Low-pressure centers can produce bad weather

in any season.

Pressure Centers and Winds

Global Winds

Atmosphere

The atmosphere

balances these

differences by

acting as a giant

heat-transfer

system.

Global Winds

Atmosphere

This system

moves warm air

toward high

latitudes and cool

air toward the

equator.

Circulation on a Rotating Earth

Atmosphere

Global Winds The prevailing wind

is the wind that

blows more often

from one direction

than from any

other.

Atmosphere

Global Winds In the United States, the Westerlies

consistently move weather from west to

east across the continent.

Normal Conditions

El Niño and La Niña

Atmosphere

El Niño

• El Niño is the name given to the periodic

warming of the ocean that occurs in the central

and eastern Pacific.

El Niño and La Niña

Atmosphere

• At irregular intervals warm countercurrents

become unusually strong and replace normally

cold offshore waters with warm equatorial

waters.

El Niño

Normal -> El Niño Conditions

El Niño and La Niña

Atmosphere

• When surface temperatures in the eastern

Pacific are colder than average, a La Niña event

is triggered that has a distinctive set of weather

patterns.

La Niña

Bell Ringer

Describe some factors about the daily

weather that are important for you to know.

Air Masses and Weather

Atmosphere

An air mass is an immense body of air that

is characterized by similar temperatures

and amounts of moisture.

Classifying Air Masses

Atmosphere

Air masses

are classified

according to

their overall

temperature

and the

surface over

which they

form.

Weather in North America

Atmosphere

Much of the weather in North America,

especially weather east of the Rocky

Mountains, is influenced by continental

polar (cP) and maritime tropical (mT) air

masses.

Weather in North America

Atmosphere

Weather in North America

Atmosphere

Continental Polar Air Masses

• Continental

polar air

masses are

uniformly cold

and dry in

winter and

cool and dry

in summer.

Weather in North America

Atmosphere

Maritime Tropical Air Masses

• Maritime tropical air masses are warm, loaded

with moisture, and usually unstable.

• Maritime tropical air is

the source of much, if

not most, of the

precipitation received

in the eastern two-

thirds of the United

States.

Formation of Fronts

Atmosphere

When two air

masses meet,

they form a

front, which is

a boundary

that separates

two air

masses.

Types of Fronts

Atmosphere

Warm Fronts

• A warm front forms when warm air moves into an

area formerly covered by cooler air.

Types of Fronts

Atmosphere

Cold Fronts • A cold front forms when cold, dense air moves

into a region occupied by warmer air.

Types of Fronts

Atmosphere

Stationary Fronts

• When the flow of air on either side of a front is

neither toward the cold air mass nor toward the

warm air mass, the surface position of the front

does not move.

Types of Fronts

Atmosphere

Occluded Fronts

• When an active cold

front overtakes a

warm front.

Bell Ringer

A

B

C

D

Which letter would most of our weather likely

come from? Explain your answer.

Bell Ringer

Summarize the factors that you have

learned in class that contribute to the

prediction of weather?

Thunderstorms

Atmosphere

A thunderstorm is a storm that generates

lightning and thunder. Thunderstorms

frequently produce gusty winds, heavy rain,

and hail.

Thunderstorms

Atmosphere

Occurrence of Thunderstorms

• At any given time, there are an estimated 2000

thunderstorms in progress on Earth. The

greatest number occur in the tropics.

Thunderstorms

Atmosphere

Development of Thunderstorms

• Thunderstorms form when warm, humid air rises

in an unstable environment.

Stages in the Development

of a Thunderstorm

Tornadoes

Atmosphere

Tornadoes are violent windstorms that take

the form of a rotation column of air called a

vortex. The vortex extends downward from

a cumulonimbus cloud.

Tornadoes

Atmosphere

Occurrence and Development of Tornadoes

• Most tornadoes form in association with severe

thunderstorms (cumulonimbus).

Tornadoes

Atmosphere

Tornado Safety

• Tornado watches alert people to the possibility of

tornadoes in a specified area for a particular time.

• A tornado warning is issued when a tornado has

actually been sighted in an area or is indicated by

weather radar.

Formation of a Mesocyclone

Tornadoes

Atmosphere

Tornado Intensity

• Because tornado winds cannot be measured

directly, a rating on the Fujita scale is determined

by assessing the worst damage produced by the

storm.

Tornado Damage

Hurricanes

Atmosphere

Whirling tropical cyclones that produce

winds of at least 119 kilometers per

hour (74 mph) are known in the United

States as hurricanes.

Satellite View of Hurricane Floyd

Hurricanes

Atmosphere

Development of Hurricanes • Hurricanes develop when water temperatures

are warm enough to provide the necessary heat

and moisture to the air.

Hurricanes

Atmosphere

Development of Hurricanes • Hurricanes form in a three step process:

1. Tropical Depression (<61 kph / <38mph)

2. Tropical Storm (62-118 kph / 39-73mph)

• This is when a name is given to the storm.

• Usually half of these become Hurricanes.

3. Hurricane (119+ kph / 74+ mph)

Atmosphere

Hurricanes

Atmosphere

Anatomy of Hurricanes • The eye is a zone of scattered clouds and calm

at the center of a hurricane.

Hurricanes

Atmosphere

Development of Hurricanes

• The eye wall is a doughnut-shaped area of

intense cumulonimbus development and very

strong winds that surrounds the eye of a

hurricane.

Cross Section of a Hurricane

Hurricanes

Atmosphere

Hurricane Intensity

• The intensity of a hurricane is described using

the Saffir-Simpson scale.

Human Impacts on the Atmosphere

Atmosphere

Human Influence

• Emissions from transportation vehicles account

for nearly half the primary pollutants by weight.

Human Impacts on the Atmosphere

Atmosphere

Acid Rain

• Acid rain is a

broad term that

includes any

form of

precipitation

that has acidic

components.

Human Impacts on the Atmosphere

Atmosphere

Acid Rain

• Acid rain is created when sulfur dioxide (SO2) is

carried into the atmosphere mainly through the

burning of fossil fuels.

Human Impacts on the Atmosphere

Atmosphere

Acid Rain

• Acid rain

can

negatively

affect plant

life, birds,

and water

sources.