The Effects of Solar Cycle Variability on D and H in the Upper Atmosphere of Mars | CU Experts

The upper atmosphere of Mars is directly affected by solar activity and; the resulting solar irradiance impinging upon it. Variations in solar; forcing can affect the rate at which atmospheric species escape from the; planetary system. Remotely sensed observations of the upper atmosphere; of Mars have been made during solar activity extrema of Solar Cycles 22; and 24. These observations were made of D and H Lyman-a emissions using; the Mars Atmosphere and Volatile Evolution (MAVEN) mission and the; Hubble Space Telescope (HST) high resolution spectrographs. Data; obtained from the two missions are analyzed and used to derive densities; and escape rates of D and H from the martian upper atmosphere. The; results show that the properties of these two water-spawned atoms vary; with solar cycle, and display significant inter-annual variability,; mainly due to variations in atmospheric temperature. The findings; suggest that cooler atmospheric temperatures due to reduced solar EUV; flux may enhance the abundance of H atoms in the upper atmosphere of; Mars, yet this does not increase their escape rates.

Mayyasi M; Clarke J; Chaufray J-Y; Bougher S; Kass D; Villanueva G; Montmessin F; Deighan J; Jain S; Schneider N

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