Mars Nitric Oxide Nightglow as observed by MAVEN/IUVS

Abstract:

We report results from a study of nitric oxide nightglow over the northern hemisphere of Mars during winter. We present observations of the nitric oxide δ and γ band emissions between 190 and 270 nm by the Imaging UltraViolet Spectrograph on the MAVEN spacecraft. The emission reveals recombination of N and O atoms dissociated on the dayside of Mars, and is known to trace upper atmosphere hemispheric circulation patterns. We extend previous studies to higher latitudes, finding brighter emissions lower in the atmosphere as predicted from global circulation models. Statistically signicant variability suggests variation of the fluxes of N and O carried from the dayside thermosphere, as well as possible variations of the wind pattern in the nightside thermosphere and mesosphere. We report unexpected variability between the individual components of the nitric oxide band system. We provide statistical characteristics and evaluate possible explanations for this phenomenon.