ozone a planetary context presented by stephen schneider deborah carlisle
TRANSCRIPT
OzoneOzoneA PLANETARY CONTEXTA PLANETARY CONTEXT
Presented by Presented by
Stephen Stephen SchneiderSchneider
Deborah CarlisleDeborah Carlisle
Interpolating Color Data
User Comments Average Red
Average Green
Average Blue
exercising 70.3 65.1 5.1resting 47.2 58.1 15.80% CO2 22.5 47.9 39.81% CO2 35.6 55.2 23.410% CO2 74.7 62.9 0.850% CO2 81.7 68.1 0.8
0% 1% 10% 50%
You can interpolate graphically ormathematically. Having calibrated samples close to the right color willimprove your accuracy.
0% CO2 resting exercising
1% CO2 10% CO2 50% CO2
Rest % = 1% + × (10% – 1%) = 1% + 0.299 × 9% = 3.7% 47.2 – 35.674.7 – 35.6
Atmospheric Absorption
• The Earth’s atmosphere absorbs most wavelengths of the radiation incident on it from space
• This is a good thing for life – high energy photons would sterilize the planet!
• It’s an intriguing coincidence(?) that our eyes work at wavelengths where the atmosphere is transparent.
Why Space-based Observatories?
Atmospheric HeatingStratosphere• Oxygen (O2) is split apart
by solar ultraviolet light, and O atoms recombine to make ozone (O3).
• O2 and O3 both absorb ultraviolet light, heating this layer.
Troposphere• Sunlight heats surface.• Atmosphere absorbs heat
from surface.
6Ozone (parts per million)
0
20
40
60
80
100
Alt
itud
e (k
m)
Troposphere
Mesosphere
Thermosphere
Ozone In the AtmosphereA
ltitude (miles)
10
0
20
30
40
50
60
90% of ozone is in the stratosphere
0 2 4 6 8
10% of ozone is in the troposphere
7
UVc - 100% AbsorptionUVb - 90% Absorption
UVa - 50% Absorption & Scattering
Ozone is the Earth’s natural sunscreen
Ozone (parts per million)
0
20
40
60
80
100
Alt
itud
e (k
m)
Troposphere
Mesosphere
Thermosphere
Altitude (m
iles)
10
0
20
30
40
50
60
0 2 4 6 8
Earth’s Energy Budget
9
October Average Ozone HoleOctober Average Ozone Hole
LowOzone
HighOzone
10
16%
32%
23%
12%
7%5%
1%4%
0
3400
3000
2000
1000
(CH3CCl3)
(e.g., HCFC-22 = CHClF2)
(CCl2FCClF2)
Naturalsources
Other gasesMethyl chloroform
HCFCs
CFC-113
Carbon tetrachloride (CCl4)
CFC-11 (CCl3F)
CFC-12 (CCl2F2)
Methyl chloride (CH3Cl)
0
20
15
10
5
15%
27-42%
5-20%20%
14%
4%
Methyl bromide (CH3Br)
Halon-1211 (CBrCIF 2)
Halon-1301 (CBrF3)
Other halons
Very-short lived gases (e.g., bromoform = CHBr3)
Chemicals that Destroy Stratospheric Ozone
• Cl is much more abundant than Br• Br is about 50 times more effective at O3 destruction
From Ozone FAQ - see http://www.unep.org/ozone/faq.shtml
Ground-level Ozone• Ozone problems are
caused by pollutants, not greenhouse gases.
• At ground level, the presence of NOx and volatile organics stimulates production of this caustic chemical.
• Ozone can cause lung damage and exacerbate breathing problems.