[October 31, 2025] Planetary Atmospheric Photochemical Model Workshop

October 31 (Friday) Planetary ATMOspheres Model (PATMO) Workshop

Venue: Sophia University Yotsuya Campus (Classroom: TBA)
https://www.sophia.ac.jp/eng/aboutsophia/access/campus/

Registration: https://forms.gle/R3Pd6Fzk6Ax5G8Rk6

Abstract: The Planetary ATMOspheres model (PATMO) is a one-dimensional (1D) photochemical model designed to study the vertical structure and evolution of planetary atmospheres. PATMO integrates chemical kinetics, photochemistry, diffusion, and isotopic effects into a single framework. The model divides an atmosphere into discrete layers, each characterized by pressure, temperature, and species abundances, and evolves them in time using stiff ODE solvers (DLSODES). Molecular and eddy diffusion are included to represent vertical mixing, while boundary conditions allow for surface emissions, gravitational settling, and deposition processes. A distinctive feature of PATMO is its treatment of wavelength-dependent photochemistry. Ultraviolet (UV) radiation is propagated through the atmosphere, with absorption cross sections resolved at high spectral resolution to capture structured bands such as O₂ Schumann–Runge. This permits the explicit modeling of isotopic effects in photodissociation, allowing isotopologues to be tracked separately and isotope ratios to be calculated dynamically. Such a capability is essential for applications ranging from Earth’s ozone chemistry to sulfur and carbon isotopic cycles relevant for planetary atmospheres. Numerically, PATMO employs a hybrid Python–Fortran architecture, where a Python preprocessor constructs customized Fortran code for the specified reaction network and planetary setup. This design allows flexibility in network size and chemical detail while maintaining computational efficiency. PATMO has been tested against the US Standard Atmosphere for ozone and UV flux reproduction, applied to sulfur photochemistry involving CS₂ and related species, and extended to photochemistry relevant to exoplanets and exomoons.
The bootcamp will incorporate an introduction to the theoretical framework and code structure of the model followed by hands-on exercises on deployment and construction of specifically designed networks. The code has been tested in most Linux-like environments such Ubuntu and most macOS operating systems. Python 3, gfortran or IntelFortan are required for compiling the code.
Schedule:
Morning section

Afternoon section

Code: https://github.com/SophiaAtmo/PATMO