5:15 PM - 7:15 PM
[U12-P02] An introduction of one-dimensional photochemical model for Archean atmosphere
Keywords:photochemical model , Archean atmosphere, atmospheric evolution , reducing, PATMO
We introduce a one-dimensional photochemical model for Archean atmosphere. The model PATMO[1] features a Python preprocessor automatically generating all necessary subroutines in Fortran 90 for atmospheric photochemistry simulation. Given a specified chemical network, the kinetic of the Ordinary Differential Equations (ODEs) system will be solved in Fortran 90 modules, which users can configure via an options file. For researchers investigating the atmospheric evolution of specified species, PATMO can offer flexibility that additional chemical reactions can be incorporated into the existing network as needed. The model dynamically updates solar attenuation condition, the opacity term, and photodissociation reaction rates at each timestep, ensuring accurate representation of photochemical species evolution. The model can flexibly apply to the present atmosphere on Earth or be adapted for exoplanetary studies by modifying the initial conditions.
In this study, the model incorporates 62 chemical species and 455 chemical reactions, simulating the vertical atmospheric column from surface to 100 km over a 100-years period. The simulation estimates the fluxes of organic materials to the surface from a reducing Archean atmosphere, which differed from the present atmosphere by having very low O2 and high concentrations of CO2 and CH4. We focus on the abundance of CO and the organic molecules generated from it. The model was validated by comparing output with previous studies [2], [3], [4] of the Archean atmosphere, demonstrating consistency with established findings.
References
[1] Danielache et al., Geochemical journal 57-2, 42-58 (2023). DOI:10.2343/geochemj.GJ23004.
[2] Zahnle et al., Geobiology, 4(4), 271-283 (2006). DOI:10.1111/j.1472-4669.2006.00085.x.
[3] Claire et al.,Geochimica et Cosmochimica Acta, 141, 365-380 (2014). DOI: 10.1016/j.gca.2014.06.032 .
[4] Pinto et al., Science 210,183-185(1980). DOI:10.1126/science.210.4466.183.
In this study, the model incorporates 62 chemical species and 455 chemical reactions, simulating the vertical atmospheric column from surface to 100 km over a 100-years period. The simulation estimates the fluxes of organic materials to the surface from a reducing Archean atmosphere, which differed from the present atmosphere by having very low O2 and high concentrations of CO2 and CH4. We focus on the abundance of CO and the organic molecules generated from it. The model was validated by comparing output with previous studies [2], [3], [4] of the Archean atmosphere, demonstrating consistency with established findings.
References
[1] Danielache et al., Geochemical journal 57-2, 42-58 (2023). DOI:10.2343/geochemj.GJ23004.
[2] Zahnle et al., Geobiology, 4(4), 271-283 (2006). DOI:10.1111/j.1472-4669.2006.00085.x.
[3] Claire et al.,Geochimica et Cosmochimica Acta, 141, 365-380 (2014). DOI: 10.1016/j.gca.2014.06.032 .
[4] Pinto et al., Science 210,183-185(1980). DOI:10.1126/science.210.4466.183.