Solar, Dust, and Tidal Effects on Martian Dayside Exospheric Temperature: An Empirical Model Based on a Decadal MAVEN/IUVS Data Set

Abstract The Martian exospheric temperature, T exo , is a fundamental parameter that regulates atmospheric escape from Mars to space. Previous studies have shown that this parameter varies significantly in response to both solar forcing and atmospheric dynamics. Accurately quantifying and modeling exospheric temperature is essential for understanding Mars’ long-term climate evolution. Using a decadal data set of Ly α airglow emission observed by the Imaging Ultraviolet Spectrograph on the Mars Atmosphere and Volatile EvolutioN mission, we derived the Martian dayside exospheric temperature under varying solar and atmospheric conditions during 2014–2023. Our analysis indicates that the Martian dayside exospheric temperature varies from ∼140 to 300 K over the past decade. Long-term variations are primarily driven by solar forcing, with a sensitivity of ∼45 K mW −1 m 2 to the solar Ly α flux measured at Mars. Short-term variations are influenced by dust activity and atmospheric tides. On average, the Martian dayside exospheric temperature is enhanced by ∼20.1 K during large-scale dust storms, and atmospheric tides lead to longitudinal variations with magnitudes of ∼10–15 K and ∼10–30 K near aphelion and perihelion, respectively. We developed an empirical model of the Martian dayside exospheric temperature through multidimensional least-squares fitting, which is capable of capturing the combined effects of solar, dust, and tidal forces. This model offers a valuable tool for estimating the Martian exospheric variability under diverse conditions.