The densities of six neutral species in the Martian upper atmosphere were analyzed before and during the 2018 Martian global dust storm (GDS 2018) using data from the Neutral Gas and Ion Mass Spectrometer of the Mars Atmosphere and Volatile EvolutioN mission. The trends of the dayside densities of the neutral species and their relative abundances were investigated between May 27 and June 17, 2018, at altitudes of 160–210 km. GDS 2018 caused variations in the neutral species abundance of the upper atmosphere at its onset in June 5–8, 2018, with the CO₂, Ar, CO, O, N₂, and He densities decreasing relative to prestorm conditions. The densities of the examined neutral species increased during the storm, except those of O and He. During the storm, the relative abundances of CO₂ and Ar increased, while those of CO and O decreased and those of N₂ and He remained the same. The variation in the neutral species with altitude was consistent with the regular atmospheric conditions and unrelated to the GDS 2018 drivers. The higher thermospheric temperature observed during the storm onset suggested that changes in the composition of the neutral species were caused by storm-induced thermal enhancements.

中文翻译：

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MAVEN观测到的2018年6月全球沙尘暴对火星高层大气大气成分的影响

使用来自火星大气和挥发性演化任务的中性气体和离子质谱仪的数据，在 2018 年火星全球沙尘暴 (GDS 2018) 之前和期间分析了火星高层大气中六种中性物种的密度。2018 年 5 月 27 日至 6 月 17 日期间，在海拔 160-210 公里处调查了中性物种的日侧密度及其相对丰度的趋势。GDS 2018 在 2018 年 6 月 5 日至 8 日开始时导致高层大气中性物种丰度发生变化，CO ₂、Ar、CO、O、N ₂和 He 密度相对于风暴前条件下降。除 O 和 He 外，被检查的中性物种的密度在风暴期间增加。在风暴期间，二氧化碳的相对丰度₂和Ar 增加，而CO 和O 减少，N ₂和He 保持不变。中性物种随海拔高度的变化与常规大气条件一致，与 GDS 2018 驱动因素无关。在风暴开始期间观察到的较高热层温度表明中性物种组成的变化是由风暴引起的热增强引起的。