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Ozone Abundance in Earth-like Planets
NTNU Earth Science Department
Shung-wen Hsu
Supervisor: Gu, Pin-Gao
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Outline
• Introduction
• About OZONE LAYER
• The SIMULATION
• Comparing to the Franck Selsis Paper
• Conclusion & Future work
Introduction
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Early Earth Atmosphere• The atmosphere formed when the core, mantle, and
crust differentiated.
• DEGAS with differentiate -- gas released form the Earth.• The original composition in the early Earth atmosphere
is : H2O、 H2、 HCl、 CO、 CO2、 N2…etc
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Index of Life?
• How to find the other life on other planets?
• By oxygen?• We can not be detected oxygen in
planet spectra, but we can detect Ozone.
• Finding creatures live on the land…?
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About OZONE LAYER
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The Stratosphere• Altitude : 10 ~ 50 km• Stable inversion layer
Thermosphere
Mesosphere
Stratosphere
Troposphere
• Locate at the stratosphere
• Heating the atmosphere and cause the inversion layer.
The Ozone layer
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The Formation of Ozone Layer
• Chapman Equations
• Reaction rate :• Fast : (1)、 (3)• Slow : (2)、 (4)• Very slow : (5)
• Timescale between
Chemistry and Transport (dynamical) .
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The Formation of Ozone Layer II• For simplify the equation, we take off the slow
reaction.
• Finally, we got this :
K1/k2 is an inverse ratio to temperature.
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Simulation
• Fortran program
• Isothermal Simulation
• Dynamic Equilibrium Simulation
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Isothermal Simulation• Assume :1. Each layer is well mixed.2. Each layer is independent ( no vertical convection
and heat transport) .3. The ozone do not heat or cool the atmosphere.4. The radiation from the ground does not be
considered.
K1/k2 is an inverse ratio to temperature.
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Isothermal Ozone Abundance
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O3 mixing ratio
• Mixing ratio air
O3
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F、 G、 K star spectra
A Stellar Spectral Flux Library: 1150 - 25000 A (Pickles 1998)
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Different Stellar Spectra in Isothermal Simulation
• We can only find that the F2V star causes higher ozone at altitude above 30km.
• The O3 mixing ratio of G2V is almost the same with the K2V.
• => We can’t get information from isothermal simulation.
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Dynamic Equilibrium Simulation• Assume :1.Each layer is well mixed.2.Each layer is independent.3.The heating effect is caused by ozone
only, and the cooling effect is caused by CO2 only. And I assume heating is equal to cooling in this simulation.
4.The radiation from the ground does not be considered.
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Heating & Cooling Rate
• Heating : caused from ozone absorb and transform UV into thermal energy.
• Cooling : caused from CO2 thermal emission to the space.
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Dynamic Equilibrium Simulation Result I
•Highest temperature
– 305k, 52km.
•The trend of the temperature maybe correct.
•The temperature difference between is much larger in the dynamic equilibrium simulation than a observed data.
Temperature Profile -- Solar Flux
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Dynamic Equilibrium Simulation Result I
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Result II – F,G,K type
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Result II – F,G,K type
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K1/k2 is an inverse ratio to temperature.
So, temperature is high, this effect will cause the [O3] drop, and oppositely, when the temperature is low, the [O3] will be more.
This effect seems to dominate my simulation!!
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Result II – F,G,K type
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Paper of Franck Selsis• DARWIN And The Atmosphere of Terrestrial Planets
K-type,low temperature, high ozone
F-type,High temperature, low ozone
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The Selsis Simulation Spectra of
Planets
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Conclusion & Future Work
• A lot of aspects do not be considered in my simulation, Ex. Scattering、 O3 cooling effect、 catalytic reaction、 incorrect UV flux…etc.
• Make the code complete, and expect the program could reflect the properties of earth-like planet atmosphere more precisely.
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The End
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Evidence in Geology
• Banded iron accumulated between about 1.9 to 3.5 billion years ago.
• Banded iron – the mineral which have not oxidized completely.
• Banded iron can not be found in the rock younger than 1.9 billion year. Banded iron