Gravity Waves and the Temperature of the Martian Thermosphere
Journal Article
Overview
abstract
Abstract; Models of the Martian thermosphere capture its complex large scale behavior essential to understanding modern dynamics and atmospheric evolution at Mars, but only match observed temperatures through the addition of gravity wave dissipation‐driven cooling. While theory and high resolution simulations suggest this cooling effect to be correct, it has never been confirmed observationally due to the thermosphere's highly complex and variable nature. In this study, we use temperatures derived from the Mars Atmosphere and Volatile EvolutioN (MAVEN) satellite's Neutral Gas and Ion Mass Spectrometer (NGIMS) and remove influence of time of day, season, and changes in EUV in order to determine any associations between temperature and gravity wave activity, measured by independent metrics Integrated Wave Power (IWP) and gravity wave potential energy per mass . We find a positive association between gravity wave activity and temperature, counterintuitively providing observational evidence consistent with gravity wave cooling. We interpret our result to mean that, as gravity waves lose IWP and , temperatures decrease. The association between gravity wave activity and temperature is stronger in the northern hemisphere regardless of season, suggesting that gravity wave cooling may be stronger there. The association is inverted in the southern hemisphere during southern summer, suggesting that the influence of gravity waves on temperature may be different than during dusty conditions. The dominance of hemispherical differences over seasonal changes in the variation of association of gravity wave activity and temperature suggests that winter Thermospheric Polar Warming may not be driven by gravity wave activity.
