Strong Variability of the Modeled Venus NO Nightglow

The ultraviolet nightglow of nitric oxide (NO) on Venus offers a unique window into the dynamics and chemistry of its upper atmosphere. We present three-dimensional simulations of Venus' NO nightglow using a ground-to-thermosphere model, revealing a strong, short-timescale variability consistent with observations. The Venus Planetary Climate Model accurately reproduces the altitude of peak emission at 115 km, matching SPICAV data, and shows an average peak brightness of 53 ± 33 kR, only 5% below the observed values. Crucially, the observed variability and morphology of the NO emission are tightly linked to atmospheric dynamics; its maxima strongly correlate with horizontal wind convergence, leading to localized subsidence. This downward transport is essential for delivering nitrogen atoms to fuel the nightglow, making it a critical tracer for understanding Venus's complex atmospheric circulation. Our findings underscore the importance of the NO nightglow as a powerful diagnostic for the solar-to-antisolar circulation on Venus.