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Ozone Abundance in Earth-like Planets. NTNU Earth Science Department Shung-wen Hsu Supervisor : Gu, Pin-Gao. Outline. Introduction. Introduction About OZONE LAYER The SIMULATION Comparing to the Franck Selsis Paper Conclusion & Future work. Early Earth Atmosphere.
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Ozone Abundance in Earth-like Planets NTNU Earth Science Department Shung-wen Hsu Supervisor:Gu, Pin-Gao
Outline Introduction • Introduction • About OZONE LAYER • The SIMULATION • Comparing to the Franck Selsis Paper • Conclusion & Future work
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
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…?
Thermosphere Mesosphere The Ozone layer • Locate at the stratosphere • Heating the atmosphere and cause the inversion layer. Stratosphere Troposphere The Stratosphere • Altitude : 10 ~ 50 km • Stable inversion layer
The Formation of Ozone Layer • Timescale between • Chemistry and Transport (dynamical) . • Chapman Equations • Reaction rate : • Fast : (1)、(3) • Slow : (2)、(4) • Very slow : (5)
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.
Simulation • Fortran program • Isothermal Simulation • Dynamic Equilibrium Simulation
Isothermal Simulation • Assume : • Each layer is well mixed. • Each layer is independent ( no vertical convection and heat transport) . • The ozone do not heat or cool the atmosphere. • The radiation from the ground does not be considered. K1/k2 is an inverse ratio to temperature.
O3 mixing ratio • Mixing ratio
F、G、K star spectra A Stellar Spectral Flux Library: 1150 - 25000 A (Pickles 1998)
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.
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.
Heating & Cooling Rate • Heating : caused from ozone absorb and transform UV into thermal energy. • Cooling : caused from CO2 thermal emission to the space.
Dynamic Equilibrium Simulation Result I Temperature Profile -- Solar Flux 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.
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!!
K-type,low temperature, high ozone F-type,High temperature, low ozone Paper of Franck Selsis • DARWIN And The Atmosphere of Terrestrial Planets
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.
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