Preliminary modelling of NOx photochemistry on Venus

The observational discovery of NO [3] in the Venus cloud layers revived interest in odd nitrogen chemistry on Venus. Based on column-integrated results from numerical modelling, the discovery paper proposed that odd nitrogen chemistry needed to be considered more closely because it might have important effects on the dominant chemical cycles on Venus [3]. A more detailed preliminary assessment of the potential impacts of odd nitrogen chemistry is being made using a 1-d global-average photochemical model. Two scenarios are being examined. One introduced heterogeneous oxidation of CO [10] and the other adjusted the thermal stability of ClCO to enhance the rate of oxidation of CO. Preliminary model simulations suggest odd nitrogen chemistry may have significant effects on specific aspects of the modelled chemistry, such as SO and SO2 abundances at 8090 km altitude [10]. However, the global-scale impact of odd nitrogen chemistry appears to be small.