Transcript Atmospheric - Penicuik High School

Atmospheric systems
100% Solar Energy
The global heat budget
Life on earth would not exist if it were not
For solar energy. (light and heat from the sun).
The diagram shows about half the energy
That enters our atmosphere is actually
absorbed by the earths surface.
What is meant by
the earth’s “albido”?
Reflected by Atmospheric Gases
and Dust
Reflected by
Clouds 17%
8%
Absorbed by 23% Atmosphere
4% Absorbed
Clouds
19% Absorbed by Water
Vapour Gases and Dust
The ability of the earth’s
surface to reflect energy
6% Reflected by
Surface
52%
46% Absorbed by
Surface
Total absorbed = 23% (Atmosphere)
46% (Earth’s surface)
= 69%
Earth Albido = 17% + 8% + 6%
= 31%
Heat lost and heat gained
The amount of heat energy received at different latitudes varies because of the
curvature of the earth. The suns rays hit the earth more directly in equatorial
areas and more at an angle in polar areas.
At X
Heat energy is more spread out because
rays come in at an angle, so there is more
land to heat up.
There is more atmosphere to pass through so
There is more heat absorbed by the water vapour.
There is more heat absorbed by dust. There is also
More heat absorbed by atmospheric gases
More heat is reflected by snow and ice (the “albedo” factor)
At Y
Heat energy is more concentrated so there is less
land to heat up.
There is less atmosphere to pass through so less
heat is reflected by dust. Less is reflected by water
Vapour. Less is absorbed by dust . Less is absorbed
by atmospheric gases.
More energy is absorbed by the dark greens and
Browns . Very little solar energy reflected by the
“albedo” factor.
Net heat gain and heat loss
So, areas near the equator are gaining heat from the sun all the time and areas near
the poles are losing heat all the time. This diagram shows those latitudes which have
a net gain of heat and those which have a net heat loss.
Q Why aren’t equatorial areas getting hotter and polar regions getting colder?
A By transfer of heat by moving air and by Ocean currents
Transfer of heat energy
The sun hits the earth at the equator at 90%.
The surface is heated and warms the air which rises. This creates low pressure.
The air spread North and South and starts to cool. The cool air sinks. This creates an area of High pressure.
Most of this air blows back to the equator to be re-heated.
Some of the air travels towards the poles where it meets cold air coming south from the North pole.
The cold polar air and the warm tropical air mix and rise.
Some circulates South to the tropics where it cools and descends.
Some circulates to the North to the North pole where it cools and sinks.
Felix jumps from edge of Atmosphere
animation of global cell patterns
The transfer of heat energy by moving water
How does it work?
The sun hits the area around the equator at right angles. This heats the water up and it expands.
The expanding water pushes North and South from the equator to the poles. It carries heat energy with it.
To compensate cold water is pushed out of the polar areas back to the equator to be re-heated. The cycle continues.
The ocean currents are also pushed along by the wind cells (Hadley, Ferrell etc).
The coriolis effect (the spin of the earth) deflects ocean currents and winds so they rotate clockwise in the northern
hemisphere and anticlockwise in the southern hemisphere.
Only in the Pacific and Atlantic do Ocean currents resemble the wind patterns, because they are large areas of water.
Ocean currents mapped
Ocean currents in the Atlantic
Complete the ocean currents for the Atlantic from
The world map on the previous page.
Describe the pattern of ocean currents in the North
Atlantic.
Explain
why cold currents flow south and the
warmer currents flow north
Jan
July
Glasgow 4
15
Moscow -9
22
Explain the temperature differences between
Glasgow and Moscow
Exam style question
Both questions below are taken from a past exam paper. (note the key words – “Explain,” “account for,” “describe”
Explain why there is a surplus of solar energy in tropical
latitudes and a deficit towards the poles (8)
Describe and account for the pattern of ocean currents
in either the Atlantic or the Pacific Ocean. (10)
Global climate change
Describe the variations in global temperature as shown in the diagram above (5)
Physical reasons for global warming
The Earth’s orbit
Shape of the orbit (rugby ball)
Angle of tilt to the sun
Time of year when earth is closest to the sun
All of these change through time
Volcanic activity
Volcanic dust in atmosphere cuts down on solar radiation (the earth cools)
Sun spots
Are cooler areas of the sun. They mean the earth receives less energy. They appear randomly.
Solar flares give out more heat.
Other natural factors
Termites
Bogs and marshes
Melting tundra
Earth Cycles and Albido
Human reasons for climate change
• Suns rays pass through the atmosphere
• They are reflected off the earths surface
• The reflected heat is a different wavelength
and can be absorbed by greenhouse gases.
• This means the atmosphere starts to heat up
Greenhouse gases are: Carbon dioxide, Methane and CFC’s
Levels of green house gases have risen because we now burn more fossil fuels than ever before
Human factors – causing global warming
More CO2
Burning fossil fuels
Deforestation of rain forest
Reducing the number of trees
More Methane
More rubbish tips
More rice fields
Burning forests
More livestock (cows)
More Cfc’s
Poor disposal of old fridges
Poor disposal of old cars with A/C
Aerosol spray cans
burning permafrost
Measuring the melting of Greenland
Largest ice carving ever filmed
Earth if all the ice melted
Gases that cause global warming
Effects of Global warming
• Sea level rises, coastal flooding (waterfront developments
in rich countries are effected)
• Less land to build on and farm
• Changes in weather patterns ( N. America to get drier, middle
East to get wetter)
• Increase in violent storms
• Ecosystems effected (some animals benefit, others suffer
and become exctinct)
• More droughts around the world
• Mass migration as people move away from dry areas
• Increase conflict as more people try to live off less land
• Countries become poorer as resources are harder to get
• Possible increase in crime as people compete for food
and resources
Solutions to Global warming
• Use more nuclear power
• Create more efficient engines that burn less fuel
• Filter the Co2 out of the coal fired power stations
• Use more Bio-Fuels
• Encourage people to use cars less
• Each country to agree to Set Co2 reduction targets
• Invest in alternative energy (wind, solar, wave, Hydro)
• Invest in reforesting areas and stop deforestation of Rainforests
• Store carbon in underground rocks (carbon sequestration)
• Create clouds by firing aerosols to reflect sun heat
one guy and a marker pen
The argument for action
The argument for action
Tropical Continental (cT)
Stable, dry air
Warm and dusty
‘Harmattan’ winds
Blow South across Sahara
desert
Tropical Maritime (mT)
Moist, unstable air
Warm, wet ‘South Western
Monsoon’ winds
Blow North towards West
Africa
The area of low pressure where the two air masses
meet is called the ITCZ. It is a belt produced by a
combination of equatorial heating and the meeting of
these winds. It migrates in response to the changing
position of the thermal equator.
• It is summer in the Southern
Hemisphere so the suns
rays are concentrated here.
• ITCZ moves south as sun moves
south
•Only the very southern coastal strip
(at X) of west Africa is affected by mT
air
•Dry, dusty Harmattan winds blow
over most of West Africa
•Only areas fairly close to the coast
experience rain. Inland it is dry.
• It is summer in the Northern
Hemisphere so the suns rays are
concentrated here.
• ITCZ moves north towards the
Tropic of Cancer.
•CT air (hot, dry and dusty) is dragged
north, well into the Sahara
•Wet moist MT winds push well
inland from the south bringing the
wet season
Match the region with the
correct climate graph and write it in