“The Tale Of Ozone Hole” IDC-601 ABHISHEK MISHRA PH14047
CONTENTS
• Motivation
• Ozone Chemistry [Stratosphere]
• Historical Timeline
• TOMS dataset / observations
• Lessons Learned
DISCRETE LAYERS OF ATMOSPHERE Z[P,T]
IMAGE SOURCE: Howstuffworks
IMAGE SOURCE: Wiki commons
‘SELECTIVE ABSORPTION’ by gases in
Atmosphere
99%[Fix],H2O,
Trace species
Dry, ozone, [m+d]
oxygen, etc.
Difficult to quantify
Any object, Temperature > 0 emits Electromagnetic/Thermal Radiation:
[WIDE SPECTRUM OF ENERGIES]
SOLAR ELECTROMAGNETIC SPECTRUM
High Energy WavesLow Energy waves
TROPOSPHERE
STRATOSPHERE
MESOSPHERE
OZONE LAYER
“HIGH ENERGY UV
[λ<300nm]
RADIATIONS NEVER
MAKE IT TO THE
EARTH’S SURFACE”
Image Source: Google images
Discovered by
Schoenbien in 1839
PHOTODISSOCITION
M: Any Air molecule
This ozone absorbs the harmful UV radiation!! Although photo dissociation of O
2
[Must be Replenished]
CHAPMAN
PROPOSED
COUPLE OF
REACTIONS
[SOURCE]
CHAPMAN’S MECHANISM [1930]
NET
The Missing Sinks were identified in the last three decades of research work!!
CATALYTIC
LOSS CYCLES
“PRE-HUMAN
INFLUENCE”
RESERVOIRMUTUAL
DESTRUCTION
They proposed that CFC’s due to their inertness could make it to the Stratosphere and
interact with the catalytic cycles. [Transport Concept]
Dr. Joseph Farman
Farman’s Research group and NASA
satellites showed a Expanding
depleted region of ozone in
Antarctica!! [1985]
A Rising Concern at that time [Anderson et al., 1989]
It was figured out in a couple of years that the reason was CFC!!
PUTTING THE PIECES TOGETHER
RESERVOIR
LOSS OF OZONE
NEW
CATALYTIC
CYCLE
A result of both experimental and Lab results
Image courtesy NASA (Mark Schoenberg, GSFC).
PSC’s [Polar Stratospheric Clouds] Jeopardise the Reservoirs
-80 degree centigrade
Hailey Station [1956]
We need to Trust our Data and Work [Honesty]
Dr. Shigeru Chubachi, Meteorological
Research Institute, Japan, measured low
ozone and an ozone hole over Syowa,
Antarctica (reported at Ozone
Commission meeting in Halkidiki, Greece
in Sept 1984)
Source: Paul Newman Ted talk
References
• Paul Newman Ted talk
• Wallace and Hobbs
• The Ozone Observatory/ the earth observatory [NASA]
• J c Farman, B G Gardiner and J.D Shanklin, [Large losses of ozone in stratosphere {nature 315 -207 (16 May 1985)}
• Mario Molina and Roland [Stratospheric Sinks for CFC’s]
• Johnson et al 1989