Unit 5
Global Circulation, Climate, Weather,
and Biogeochemical Cycles
Pressure Changes in the Atmosphere
• Observe the diagram
showing atmospheric
pressure vs. altitude
• What conclusions
can be made about
the relationship
between pressure
and altitude?
• Where in the atmosphere is the majority of “air”
molecules located?
• What does that mean about the air as altitude is
increased?
Thermal Structure of
the Atmosphere
• What do these graphs
tell you about the
thermal structure of
the atmosphere?
Height and Structure of the Atmosphere
• Atmosphere can be divided vertically into four
layers based on temperature
• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
Study the diagrams on the next few pages to infer
what you know about each layer…
• Troposphere:
– weather phenomena
– Thickness varies with latitude and season
– Temperature decreases as altitude increases
• Stratosphere:
– Temperature begins gradual increase with
altitude increase
– Ozone layer concentrated here
– Since Ozone layer absorbs UV radiation from
sun, stratosphere is heated
– Commercial Planes Fly
• Mesosphere:
– Temperature decrease with altitude
– Meteors burn up
• Thermosphere
– Contains tiny fraction of atmosphere’s
mass
– Temperatures increase because oxygen and
nitrogen absorb short-wave, high energy
solar radiation.
Think, Pair, Share
1. List the four layers of the atmosphere in order
from lowest to highest.
2. Where is the ozone layer located in the
atmosphere?
3. Describe the thermal structure of the
atmosphere (i.e. how does temperature
change as you move away from Earth’s
surface?)
4. Explain how pressure changes as altitude
increases.
1. Weather occurs in the?
2. Propeller aircraft and commercial jets fly in
the?
3. Special air force jets can even fly in the?
4. Meteors generally burn up in the?
5. Auroras (Northern Lights) occur in the?
6. The troposphere is the only layer in which
humans can live without using special
equipment for existence. Why?
7. Describe the temperature change in each
layer as the altitude increases:
Ocean Temperature Variation
• Water temperature
varies with the
amount of solar
radiation received.
• Function of Latitude
(depends on where
located on Earth)
• Where would you
find highest temp?
Lowest temp?
Why?
Ocean Circulation
What powers ocean circulation?
1. Winds
2. Density Differences
• Ocean Currents = Masses of ocean water that
flow from one place to another (convection)
• Can be:
– Large or small
– Surface or deep
– Simple or complex
Ocean Surface Currents
Surface Currents
• Horizontal Movements in upper part of ocean
surface
What causes them?
• Friction between ocean and wind that blows
across surface
• Can be in small areas for short time to almost
permanent, covering vast areas
• Related to general circulation pattern of
atmosphere.
Gyros = a circle
Gyres
• Huge, circular moving current systems
5 main ocean gyres:
1) North Pacific
2) South Pacific
3) North Atlantic
4) South Atlantic
5) Indian Ocean
• Coriolis Effect -- Deflection of currents away from their
original course as a result of Earth’s rotation
• Because of Earth’s rotation, currents are deflected
clockwise in the Northern Hemisphere and
counterclockwise in the Southern Hemisphere
Ocean Currents and Climate
• Currents have important effect on climates
• When currents from low-latitude regions move
into higher latitudes, they transfer heat from
warmer to cooler areas on Earth (convection)
• EX: Gulf stream carrying heat to Europe making
their winter temps warmer than expected.
• As cold water currents travel toward the
equator, they help moderate the warm
temperatures of adjacent land areas.
• Effects of warm currents felt mostly in mid
latitudes in winter.
• Cold currents felt mostly in tropics (or) mid
latitudes during summer
• Warm currents begin in low latitude while cold
currents begin in high latitude
Key Ideas to remember:
• Heat flows from warmer objects to cooler
objects
• Ocean currents account for ¼ of Earth’s heat
transport.
Think, Pair, Share…
1. How do surface currents develop?
2. How do ocean currents affect climate?
3. What is the Coriolis effect? How does it
influence the direction of surface currents
flowing in the ocean?
Critically Thinking:
• The average surface water temperature off of the coast
of Ecuador is 21oC while it is 27oC off the coast of Brazil
at about the same latitude. Explain why there is such a
difference in water temperature between these areas at
the same latitude.
Explanatory
Paragraph
• During the 1700s, mail ships sailed back and forth between
England and America. It was noted that it took the ships two
weeks longer to go from England to America than to travel the
same route from America to England. It was determined that the
Gulf Stream was delaying the ships. Write a paragraph explaining
why this is true. Use the figure above to explain how sailors could
avoid the Gulf Stream when sailing to America
RAFT Project with picture
• Write a trip diary or travel journal from the
point of view of a water molecule writing to his
family about his trip around a gyre. Be sure to
include his movement as well as how his
temperature has changed.
• Role = Water Molecule
• Audience = Family
• Format = Trip Diary/ Journal
• Topic = Trip around a gyre
Now that we are done looking at heating
oceans and ocean currents, it is time to
begin looking at the atmosphere…
You’ll probably find that there isn’t a
lot of difference between the two.
Temperature Inversions
Temperature Inversions
• A layer in the atmosphere where the temperature increases
rather than decreases with height
• Cool Air becomes trapped below warm air.
• What types of things can cause this?
• What would be the effects of this?
Understanding Air Pressure
• Pressure exerted by the
weight of air.
• Measured by a
barometer
• Exerted in all directions
• Air pressure pushing
down on an object
balances the air pressure
pushing up on the object.
Understanding Air Pressure
• Using the ideas of air
pressure, explain why
the column of
mercury rises when
air pressure increases.
Understanding Earth’s Wind
• Wind is the result of horizontal differences in
air pressure
• Air flows from areas of high pressure to areas
of lower pressure. (diffusion)
• Unequal heating of Earth’s surface generates
pressure differences
• Solar energy is the ultimate energy source for
most wind.
Factors Affecting Wind
1. Pressure Differences
2. Coriolis Effect
3. Friction
Pressure
Differences
• Isobars – lines on a map that connecting places of equal
pressure. Spacing indicates pressure changes
• Pressure changes are expressed as Pressure Gradient.
• Wind generated when air moves from places of high
pressure to low pressure
Looking at
Isobars
• Closely spaced isobars indicate steep pressure
gradient (High Winds)
• Widely spaced isobars indicate weak pressure
gradient (Light Winds)
Coriolis Effect
Coriolis Effect
Coriolis Effect
Coriolis Effect
• Describes how Earth’s rotation affects moving
objects
• Free-moving objects (water, wind, etc) are
deflected clockwise in the Northern
Hemisphere and to the counter-clockwise in
the Southern Hemisphere.
Think, Pair, Share…
1. Why don’t objects such as a table collapse under
the weight of air above them?
2. Suppose the height of a column in a mercury
barometer is decreasing. Explain what is
happening in the surroundings?
3. What is the ultimate energy source for most
winds?
4. Explain how the Coriolis effect influences motion of
free-moving objects.
5. Describe an example of unequal heating of Earth’s
atmosphere that could lead to air pressure
differences that ultimately influence wind.
Pressure Centers and Winds
Winds move clockwise & away from High Pressure
Winds move counter clockwise & towards Low Pressure
Opposite circling is true for the Southern Hemisphere
Weather and Air Pressure
Weather and Air Pressure
• Rising air is associated with cloud formation
• Sinking air produces clear skies
• Air being drawn in to Low Pressure Center is
pushed upward (as pressure increases)
• Air is pushed away aloft as it converges in a
High Pressure Center where it drops and is
then pushed outward away from the High
pressure Center.
Barometer Rising and Falling…
Circulation if Earth didn’t Rotate
Circulation on Rotating Earth
Complex Global Circulation
Local Winds and Sea Breezes
Why is there a difference in movement of
air in the day vs. the night?
Local Winds
Clouds form over mountains
in afternoon when it may be clear
in the morning
Think, Pair, Share
1. Describe how winds blow around pressure
centers in the Northern Hemisphere.
2. Describe how the atmosphere balances the
unequal heating of Earth’s surface.
3. In general, what type of weather can you
expect if a low pressure system is moving into
your area?
4. Explain how Local Breezes work at the beach.
5. Explain how Local Breezes work in the
Mountains.
How does global Circulation affect
types of Biomes around the Globe?
World’s Biomes
What connections can you see?
What type of climate is
by “sinking air”?
What type of climate is by “rising air”?
Global Distribution of Biomes
• Rainforests are located at specific latitudes
on Earth (rising air) 0o and 60o
• Deserts are distributed at specific latitudes
on Earth (sinking air) 30o and 90o
Think, Pair, Share
1. What are local winds, and how are they
caused?
2. Explain how global circulation patterns are
connected to global biome distribution.
3. What type of pressure zone is associated
with deserts?
4. What type of pressure zone is associated
with rain forests?
5. When do sea breezes typically originate?
Heating the atmosphere
• Heat is the energy transferred from one object
to another because of a difference in their
temperatures.
• Three mechanisms of energy transfer as heat
are conduction, convection, and radiation
• What does your group know about those
terms?
Radiation
• While conduction and convection need material
to travel through, radiant energy can travel
through the vacuum of space.
• All objects emit radiant energy
• Hotter objects radiate more total energy per unit
area than colder objects do.
• Hottest radiating bodies produce the shortest
wavelengths of maximum radiation
• Objects that are good absorbers of radiation are
good emitters as well
• Energy enters the Earth system primarily as
solar radiation and eventually escapes as
heat
• 70% absorbed by earth or the atmosphere
• 30% reflected back into space
What Happens to Solar Radiation?
What happens to solar radiation?
•
When radiation strikes an object, there are three
different results:
1. Some energy is absorbed by object
2. Some substances (air & water) are transparent
to certain wavelengths of radiation (energy is
transmitted right through)
3. Some radiation may bounce off the object
without being absorbed or transmitted.
What Happens to Solar Radiation?
Reflection vs. Scattering
• What is the difference between reflection and
scattering of light?
• How might they effect the surroundings differently?
Fate of incoming solar radiation
• Reflection:
– Where does light go that is reflected?
– How does reflected light effect the surroundings?
• Absorption:
– Why would an object absorb solar radiation?
– What happens to an object that absorbs solar
radiation?
– Objects that absorb energy reradiate it
• Photosynthesis:
– Plants use energy (sunlight) to produce energy storage
molecule (glucose)
– Energy is absorbed, but not reradiated
Think, Pair, Share
1. List and explain the three mechanisms of
energy transfer as heat.
2. Explain what happens to solar radiation.
3. Describe the terms reflection, absorption, and
photosynthesis and how they relate to solar
radiation.
Climate vs. Weather
• What are they? What’s the difference?
Weather:
• Condition of atmosphere in terms of
temperature, atmospheric pressure, wind, and
precipitation (short term)
• EX: Rain, Sunny, Windy, etc
Climate:
• Long-term average of a region’s weather
• temperature, precipitation, and wind
• EX: Rainforest, Desert, etc
Why is there a need to transfer energy on Earth?
• Earth receives unequal amounts of energy from
the sun
• Creates unbalance so currents are used to
balance out energy
What is the ultimate cause of “wind” on Earth?
• Unequal absorption of energy from the sun
What factors affect a region’s weather?
Climate and Weather
• Involves transfer of energy into and out of the
atmosphere
What is ultimate source of Earth’s Energy?
• The Sun
What is utilized in transferring energy?
• Ocean and Air Currents
Explain in what direction air travels in our
atmosphere.
• Travels from High to Low Pressure
Explain how Earth attempts to balance the
unequal amount of energy shown below.
Earth’s Changing Climate
• How do you think Earth’s climate has changed
over time?
• What types of events could have caused these
changes?
• Know how Earth’s climate has changed over
time corresponding to changes in Earth’s
geography, atmospheric composition, and other
factors, such as solar radiation and plate
movement
Earth’s
Changing
Geography
Explain how this movement
Might affect the continental
climates
Earth’s Changing Climate
What types of natural processes can change Earth’s
climate:
• Volcanic Eruptions
• Ocean Circulation
• Solar Activity
• Earth Motions
What human impacts can change Earth’s Climate?
• Greenhouse Effect
• Global Warming
Volcanic Eruptions
• Releases aerosols
(volcanic ash, dust,
and sulfur-based
gases)
• Aerosols increase
amount of solar
radiation reflected
back into space
• What would impact
on Earth be?
• Lower Atmosphere
would cool
Ocean Circulation
• How does ocean circulation affect climates?
• Changes can occur in ocean circulation, that can result
in short-term climate fluctuations (El Nino, La Nina, …)
Solar Activity
• Formation of sunspots
corresponds with warm
periods in Europe and
North America
• May cause short-term
climatic change
• Why?
• Mountain Ranges create
Rain Shadow Effect.
• Wet Side and a Dry Side
• Huge affect on the climate
Rain Shadow Effect
Earth Motions
• Cause Long Term
Changes
• Geographic changes
in land and water
bodies cause
climate change
• Earth’s tilt and
rotation affect
climates as well
Greenhouse Effect
• Natural Warming of
Earth’s Lower
Atmosphere and Earth’s
surface
Global Warming
• Increases in Carbon Dioxide levels (and other
greenhouse gases) has caused global temperatures to
increase
• Makes a thicker “blanket” over Earth
Computer models are used to predict the effects of the increase in
Greenhouse gases on climate for the planet as a whole and for
specific regions
America’s
Changing
Landscape
What effect does this have on
Earth’s atmosphere? Explain
Greenhouse Gases
• Carbon Dioxide (CO2), Methane (CH4), and
Water Vapor (H2O) help maintain a warm
temperature near Earth’s surface.
• These gases help absorb heat from the sun
and then reemits that energy to Earth.
What is the Greenhouse Effect?
Global
Warming??
Why would
human action enhance
Greenhouse Effect??
How is temperature and
CO2 levels related?
Human impact on Climate Changes
Greenhouse Effect
• Natural warming of both Earth’s lower
atmosphere and Earth’s surface
Global Warming
• Global temperatures have increased as a result
of increases in carbon dioxide levels, as well as
other greenhouse gases.
Human impact on Climate Changes
Greenhouse Effect
• Natural warming of both Earth’s lower
atmosphere and Earth’s surface
Global Warming
• Global temperatures have increased as a result
of increases in carbon dioxide levels, as well as
other greenhouse gases.
What’s happened to CO2 levels over the last
150+ years?
• Why did it seem constant for so long and then
suddenly begin to spike? What do you believe would
cause it?
America’s
Changing
Landscape
What effect does this have on
Earth’s atmosphere? Explain
Think, Pair, Share
1. Describe how the greenhouse effect works
and impacts Earth.
2. Explain some causes for global warming.
3. Describe how the greenhouse effect can have
an impact on global warming based on human
activity.
4. Which atmospheric gases absorb the Earth’s
thermal radiation? What collective name do
scientists give these gases?
What will
result if
this
continues?
• During 20th century (1900s), Earth’s average
surface temperatures increased about 0.6oC
• Scientists predict that by the year 2100,
temperatures will increase by 1.4oC to 5.8oC.
Explain why increased atmospheric CO2 could
cause increase to Earth’s average temperature.
Think, Pair, Share
1. Explain the terms climate and weather.
2. What is the ultimate cause for wind on Earth?
3. Explain how the following can change Earth’s climate:
–
–
–
–
Atmospheric composition
Plate Movement
Solar radiation
Geography
4. Describe natural causes that can affect climate
5. Describe human causes that can affect climate
Each element on Earth moves among reservoirs, which exist
in earth, in oceans, in the atmosphere, and within
organisms as part of biogeochemical cycles
Focus Questions for Diagrams:
• Analyze the atmosphere, oceans, biomass and
inner earth to study the following:
1.What are the major reservoirs of the element?
2.Trace the movement of the element between at
least 3 reservoirs.
The Carbon Cycle
The “Basic” Carbon Cycle
1. Plants use carbon during
photosynthesis to
produce Oxygen and
Sugar
2. Animals take in oxygen
and sugar during
respiration to produce
Carbon Dioxide
The “Global” Carbon Cycle
The “Global” Carbon Cycle
•
1.
2.
3.
4.
Analyze the atmosphere, oceans, and inner
earth to study the following:
What are the physical forms of Carbon from the
picture?
What are the chemical forms of Carbon from
the picture?
What are 3 major reservoirs of Carbon on our
planet?
Trace the movement of carbon between at least
3 reservoirs.
The Water Cycle
The Water Cycle
•
1.
2.
3.
4.
Analyze the atmosphere, oceans, and inner
earth to study the following:
What are the physical forms of water from the
picture?
What are the chemical forms of water from the
picture?
What are major reservoirs of water on our
planet?
Trace the movement of water between at least
3 reservoirs.
Why does matter cycle between reservoirs?
• Many elements are essential for survival
• Organisms can’t create them on their own.
• Cycling of nutrients allows organisms to obtain
what is necessary for life.
• Movement of matter between reservoirs is driven
by Earth’s internal and external sources of energy.
Why should we care?
• Discuss with your group why each of the cycles
are important for your life (Carbon, Water)