Benchmarking Photolysis Rates with Socrates (24.11): Species for Earth and Exoplanets

TL;DR

This paper presents updated photolysis rates for Earth and exoplanet atmospheres using the Socrates scheme, comparing results with past data and providing benchmarks for different stellar irradiance conditions.

Contribution

It introduces a new set of benchmark photolysis rates for various species under solar and M dwarf star irradiation, improving upon previous datasets.

Findings

Good agreement with previous photolysis data, with some discrepancies due to updated parameters.

Higher UV flux from M dwarfs increases photolysis rates for high-threshold reactions.

Provides benchmark data useful for atmospheric modeling of Earth and exoplanets.

Abstract

Using the Socrates photolysis scheme, we present newly calculated photolysis rates under modern Earth atmospheric conditions for species directly relevant to Earth and species relevant to different atmospheric compositions. We compare to a previous photolysis comparison exercise, namely PhotoComp 2011. Overall, we find good agreement between our results and previous work, with discrepancies usually caused by the implementation of temperature or pressure dependent quantum yields and updated cross-section data. We provide a new set of benchmark photolysis rates for additional species both for Solar irradiance and when irradiated by an M dwarf host star. In general, the higher actinic flux at far-UV and shorter wavelengths of the M dwarf compared to the Sun drives increased photolysis rates for reactions with high threshold energies. This work provides an updated set of benchmark results for further studies of photolysis in the Earth's atmosphere and that of other planets.