Ten years of Martian nitric oxide nightglow observations

Abstract

AbstractWe present 10 years of Martian NO nightglow Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars observations in limb and stellar occultation modes. The NO nightglow is used as a tracer of the summer‐to‐winter hemispherical circulation in the upper atmosphere of Mars. Its distribution roughly follows the curve latitude = −80 sin(solar longitude), with deviations. We find that the peak brightness is 5 ± 4.5 kR, situated at 72 ± 10.4 km. It ranges from 0.23 to 18.51 kR and from 42 to 97 km. These values are consistent with previous studies. We also present maps of the brightness of the NO emission peak and its variability, an important factor that can reach up to 50% of the emission and is not reproduced by average brightness model maps. The characteristics and factors that may control the emission are investigated. In particular, we show that the solar activity exerts a positive influence on the number of detections. It does not influence, on the contrary, the brightness or altitude of the peak of the NO nightglow emission. Results presented in this study lead to future comparisons with global Martian atmospheric models and observational targets for the Imaging Ultraviolet Sprectrograph Mars Atmosphere and Volatile Evolution.