TROPICS: insolation high year round, high sun angle and ...Ozone depletion What is ozone? ... Carbon...
Transcript of TROPICS: insolation high year round, high sun angle and ...Ozone depletion What is ozone? ... Carbon...
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GEO 101, February 6, 2014
Finish insolation variation
Global environmental issues associated with insolation
TROPICS: insolation high year round, high sun angle and ~ constant duration
MID-LATITUDES: insolation highest at summer solstice, higher sun angle and longer day, lowest at winter solstice due to low angle and short day
Poles: insolation highest at summer solstice due to 24 hour duration low angle sun, none at winter solstice
Total annual insolation decreases as latitude increases
Seasonality (difference between winter and summer) increases as latitude increases
Global average annual energy balance
Surplus
DeficitTropics
Mid-High latitudes
San FranciscoSt. LouisWashington DC
Insolation on the June SolsticeComparison between top of atmosphere and Earth surface
Top of atmosphere
N. P
ole
Eq
uat
or
Duration factor23.5°N
90°N
80°N
70°N
60°N
50°N
40°N
30°N
20°N
10°N
00°N
10°S
20°S
30°S
40°S
50°S
60°S
70°S
80°S
90°SJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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48
40
44
3236
2824
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0
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90° sun elevation
Meg
ajo
ule
s/m
2 /d
ay
At
top
of
the
atm
osp
her
e
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0 0 0 0 0 0244039 4420 1
Chart monthly insolation at the North Pole
44
40 36 32 28
2024
16
12
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4
812
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2024
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32 36
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Chart of monthly insolation at the North Pole(dark bars = N.P., light are Equator for reference)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
5
45
35
25
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40
30
20
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Chart monthly insolation at the South Pole
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
44 25 06 0 0 0 0 0 17 37 49
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16
20
24
28
32
36
40
44
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90° S
Example only, do not use your sheet for this demo. problem.Class assignment: if your last name begins with
A-B, do 80°N and 10°S
C-D, do 70°N and 20°S
E-H, do 60°N and 30°S
I-L, do 50°N and 40°S
M, do 40°N and 50°S
N-Q, do 30°N and 60°S
R-T, do 20°N and 70°S
U-Z, do 10°N and 80°S
Graphs will be due on Tuesday
Incoming shortwave radiation
Outgoing longwave radiation
Ultraviolet Thermal infrared
Shortwave infrared
Visible light
From sun to earth
From earth to space
50%41%9%
Two global environmental issues related to interaction of atmospheric gases, insolation, and outgoing Earth radiation
Ozone Greenhouse gases
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For greenhouse warming and ozone depletion, be able to explain:
•basics of how it works
•problem
•causes of the problem
•consequences
•possible solutions
O2
O3
Earth’s atmosphere is unique: not at chemical equilibrium (entropy). Highly reactive atmosphere reveals life.
N2
Ozone depletion What is ozone?
Naturally occurring form of oxygen with 3 oxygen atoms in molecule instead of usual two.
O2 is what we need to breathe
O3 is a highly reactive gas
(like breathing chlorox fumes)
~400 mya
~2.4 bya
~3.7 bya
~4.6 bya
Land plants
Photosynthetic bacteria
Single cell organisms
Earth formed
Oxygen revolution
Sulfur dioxide
Nitrogencompounds
Life (as we know it) evolved under ozone layer protection
Carbon dioxide
Methane
Where is ozone?
90% of O3 found in stratosphere
good ozone: blocks UV radiation
10% of O3 near Earth’s surface
bad ozone: toxic to life
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Normal equilibrium
O2 + UV O + O
O2 + O O3
O3 + UV O2 + O
Most O3 produced in tropical stratosphere and transported poleward
Manmade chemicals interfere with equilibrium
Man-made chemicals that destroy ozone
•CFCs (chlorofluorocarbons), HCFCs: refrigerants, foam blowing agents, aerosol propellants
•Halons: old fire extinguishers
•Carbon tetrachloride: solvent
•Methyl chloroform: solvent, aerosols, cleaners, (labeled as 1,1,1-trichloroethane)
•Methyl bromide: pesticide (soil fumigant) used heavily on tomatoes and strawberries (Banned in 2005)
All are long lasting
Global environmental problem
Identified in 1980s
Stratospheric O3 concentrations decreasing
Most noticeable in Antarctica
TOMS = Total Ozone Mapping SpectrometerOMI = Ozone Monitoring Instrument
0.0
5.0
10.0
15.0
20.0
25.0
30.0
1975 1980 1985 1990 1995 2000 2005 2010 2015
Ozone Hole Area in million km2
How do CFCs destroy ozone?
Ultraviolet radiation strikes a CFC molecule
C
Cl ClCl
F
...and causes a chlorine atom to break away
Cl
Chlorine atom collides with an ozone molecule
OO
O
How do CFCs destroy ozone?
...creates molecule of regular oxygen and chlorine monoxide
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ClO
O
How do CFCs destroy ozone?
Free oxygen atom collides with chlorine monoxide
...yields a molecule of regular oxygen and a free chlorine atom
chlorine is freed to react again
In winter, chlorine attaches to ice clouds in stratosphere above pole. This keeps ozone-depleting chlorine “locked up”
When ice melts in spring (September in Antarctica), chlorine is freed and attacks O3 “hole”
http://ozonewatch.gsfc.nasa.gov/
What’s so bad about it?
1% ozone loss ~
5-7% increase in skin cancer
Cataracts
Immune system suppression
Inhibits plant growth
Globally, what’s being done about it?
Montreal Protocol, 1987
World production
World production
Montreal Protocol relatively successful because
1. Problem obviously man-made
2. Scientists agreed on cause and solution
3. No major country’s economy based on CFCs
You personally can:
•FIX leaky auto air conditioners
(#1 CFC, HCFC, HFC source in US)
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Greenhouse warmingWhat are greenhouse gases?
Range is from blue (low) to red (high)
What are anthopogenic greenhouse gases?Approximate percent responsibility for problem
Halocarbons
How does it work?
GG
http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.htmlhttp://cdiac.ornl.gov/trends/co2/jubany.html
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Are current CO2 levels that unusual?
Ice core records
http://www.ncdc.noaa.gov/cag/time-series/global
Global Land and Ocean Temperature Anomalies1880 - present
http://www.ncdc.noaa.gov/cag/time-series/globalCauses of CO2 concentration increase
Deforestation
Burning of fossil fuels
Causes of CO2 concentration increase What are fossil fuels?
Gas
Liquid
Solid
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Top Ten CO2 emitters in 2008 (million metric tons of carbon/ year)
http://www.ucsusa.org/global_warming/science_and_impacts/science/each-countrys-share-of-co2.html
2008 per capita fossil-fuel CO2 emission rates. expressed in metric tons of carbon.
Consequences may be
• Higher sea levels due to ocean expansion and ice melting (inundation of island nations)
• More intense storms
• Disruption of agriculture
• Extinctions
• Spread of tropical diseases
What’s being done globally?
Kyoto Protocol: 1997 : agreement to reduce greenhouse gas emissions by % of 1990 levels.
Entered into force on February 16, 2005
United States never ratified protocol
Kyoto Protocol not as successful because
1. Problem itself highly debated
2. Developed countries’ economies based on fossil fuels
3. Developing countries’ forests are source of income
4. China’s energy needs met by coal
Much more expensive to implement Kyoto Protocol
What can you do personally ?
Conserve energy
Drive fuel efficient vehicle
Insulate home
Recycle (saves energy)
on-campus paper and aluminum
Plant trees
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