MAVEN/IUVS observations of middle and upper atmosphere during solar minimum

Abstract:

The upper atmosphere of Mars, including the upper mesosphere and thermosphere, provides the main reservoir for atmospheric escape. The knowledge of the present state of the Martian upper atmosphere is an important component of understanding the interactions of Mars with its space environment, its coupling from lower/middle atmosphere, and escape of Martian upper atmosphere. MAVEN has been taking observations of the Martian middle and upper atmosphere for about six earth years (starting in 2014) and during this time the solar activity has gone from moderately maximum to minimum. Though, the seasonal variations in the Martian upper atmosphere are quite pronounced due to the large orbital eccentricity of Mars. These continued MAVEN observations of upper and middle atmosphere have provided an unique data set to qualitatively study the effects of seasons, solar EUV forcing, and atmospheric dynamics on the Martian thermosphere. We will present densities and temperatures measurements from 70 - 180 km made by the Imaging Ultraviolet Spectrograph (IUVS) aboard the MAVEN spacecraft from 2014 to 2020. By simultaneously measuring the temperatures and densities of the middle and upper atmospheres of Mars, our analysis would quantify the role of lower atmosphere coupling and solar EUV forcing in the observed temperature variability.