Wind measurements in Mars' middle atmosphere: IRAM Plateau de Bure interferometric CO observations

R. Moreno (1) , E. Lellouch (1) , F. Forget (2) , T. Encrenaz (1) , S. Guilloteau (3, 4, 5) , E. Millour (2)

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
3 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
4 OASU - Observatoire aquitain des sciences de l'univers
5 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]

The IRAM Plateau de Bure Interferometer has been used to map the CO(1–0) rotational line in Mars' middle atmosphere. Absolute winds and thermal profiles were retrieved during the 1999, 2001, 2003 and 2005 planet's oppositions. The observations sampled various seasons (L=143, 196, 262, 317 and 322), and different dust situations (clear, global storm, regional storm). The absolute winds were derived by measuring directly the Doppler lineshifts. The main zonal circulation near 50 km is dominated by strong retrograde winds, with typical velocities of 70–170 m/s, strongly varying seasonally, latitudinally, and longitudinally (in particular between morning and evening). Comparison of the retrieved temperature with a general circulation model indicates that the model often underestimates the temperatures in the middle (20–50 km) atmosphere, and overestimates them above 50 km.

Mots clés: Mars; Atmosphere; dynamics

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

R. Moreno, E. Lellouch, F. Forget, T. Encrenaz, S. Guilloteau, et al.. Wind measurements in Mars' middle atmosphere: IRAM Plateau de Bure interferometric CO observations. Icarus, 2009, 201 (2), pp.549-563. ⟨10.1016/J.ICARUS.2009.01.027⟩. ⟨hal-00404733⟩