Photodissociation in the atmosphere of Mars: impact of high resolution, temperature-dependent CO₂ cross-section measurements

We find that the adoption of 50 Å intervals for the purpose of computational efficiency results in errors in the calculated values for photodissociation of CO₂, H₂O, and O₂ which are generally ≤ 10%, but as large as 20% in some instances. The inclusion of temperature-dependent CO₂ cross-sections is shown to lead to a decrease in the diurnally averaged rate of CO₂ photodissociation as large as 33% at some altitudes, and increases of as much as 950% and 80% in the photodissociation rate coefficients of H₂O and O₂, respectively. The actual magnitude of the changes depends on the assumptions used to model the CO₂ absorption spectrum at temperatures lower than the available measurements, and at wavelengths longward of 1970 Å. -from Authors