Thermospheric density responses to Martian dust storm in autumn based on MAVEN data

The unique seasonal surface dust storms on Mars have a significant impact on the Martian atmosphere. However, due to the lack of observations, semi-empirical models are difficult to simulate the density changes in the thermosphere with the existence of dust storms in detail. Data from multiple Mars probes now offer new opportunities to study the detailed response of Martian dust storms to the upper atmosphere. In this paper, we use MAVEN accelerometer and mass spectrometer to study the variations of the Martian thermosphere density in autumn between MY 32 and MY34 (The corresponding Earth dates: February 11, 2015 to February 28, 2019), and use the seasonal model with dust storm index to fit the annual data of the above three Martian years. The results show that the thermosphere density has a clear response to the surface dust storm activity. Furthermore, the spatial distribution of measured data in autumn (northern hemisphere) is compared with the atmospheric density distribution simulated by the general circulation model (GCM) under specific initial conditions. The model simulation results agree well with the thermospheric density distribution characteristics of each Martian year under the initial strong dust storm conditions. It proves the important role of global dust storm in changing the structure of the Martian thermospheric atmosphere.