EARTH SCIENCE ES02 - Atmosphere · atmosphere at any given time and place. Composition of the...
Transcript of EARTH SCIENCE ES02 - Atmosphere · atmosphere at any given time and place. Composition of the...
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.