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Communication Dans Un Congrès Année : 2021

Odd oxygen photochemistry of Martian atmosphere and the role of dust

Résumé

Though the photochemistry of Mars is comparatively simple, the orbital properties of Mars and its exposure to solar influx lead to pronounced seasonal and latitudinal variations of short lived species (trace gases). In a recent analysis of SPICAM observations in the UV, we have studied spatio-temporal variability of ozone. We further use the photochemistry coupled LMD GCM to study in detail the important source and sink processes of odd oxygen Ox (ozone and oxygen atoms) and their contribution in different locations and seasons. Ox is in photochemical equilibrium up to about 30 km in the aphelion season and up to 45 km in the perihelion season. In the photochemical equilibrium domain, HO$ _{2}$+O is the dominant loss process of Ox, while above this domain, the HO$ _{x}$+O, H+O$ _{3}$ and O+O reactions have comparable contributions to the Ox loss. From SPICAM observations, we have found a correlation of ozone with dust. In southern tropical latitudes, the columnar ozone is seen to increase during a global dust storm year (MY 28) compared to the ozone column values during a year without global dust storm (MY 27). This indicates towards the radiative impact of dust on ozone. We have also studied the role of heterogeneous chemistry on dust in determining production of ozone and related tracers, by a 1D photochemical model developed at PRL and the LMD GCM. The sensitivity of input parameters taken by us in the study of heterogenous chemistry such as sticking coefficients, was also analysed.
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Dates et versions

insu-04438976 , version 1 (05-02-2024)

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Varun Sheel, Franck Lefèvre, Ashimananda Modak. Odd oxygen photochemistry of Martian atmosphere and the role of dust. 43rd COSPAR Scientific Assembly, Jan 2021, Sydney, Australia. pp.Abstract C3.2-0011-21 (oral), id.761. ⟨insu-04438976⟩
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