Wave Spectral Changes in the Thermosphere and Ionosphere Related to the PEDE 2018 Dust Event on Mars Observed by MAVEN NGIMS

Abstract In this study, we compare responses of the thermosphere and ionosphere to a planet encircling dust event in 2018 (PEDE 2018) occurred at the beginning of June 2018, a rare event last observed in 2007. Using the data from NGIMS (Neutral Gas and Ion Mass Spectrometer) instrument onboard MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft, we examine wave signatures and their spectral changes of three neutral species (O, Ar, CO 2 ) and three ion species (O + , O 2 + , CO 2 + ). Compared to low‐dust period, the following salient features stand out: (a) Wave activities (amplitudes) are significantly enhanced in the neutral species, but with smaller enhancement in the ion species; (b) The apparent wavelengths in the neutrals shift and broaden from a range of 50–300 km to 80–400 km, with dominant wavelength shifting from 100 to 200 km; (c) The apparent wavelengths in the ions shift and broaden from a range of 80–300 km to 100–400 km, with dominant wavelength shifting from 150 km to 250–300 km; (d) The correlations among the wavelength distributions of various species are high with correlation coefficient above 0.57 during low‐dust period and above 0.69 during PEDE 2018. These observed changes in wave signatures likely reflect filtering effects caused by changes in the middle atmosphere circulation induced by the global dust storm.