Thermal Tides in the Martian Atmosphere Near Northern Summer Solstice Observed by ACS/TIRVIM Onboard TGO

Siteng Fan (1) , Sandrine Guerlet (1, 2) , Francois, Forget (1) , Antoine Bierjon (1) , Ehouarn Millour (1) , Nikolay Ignatiev (3) , Alexey Shakun (3) , Alexey Grigoriev (4) , Alexander Trokhimovskiy (3) , Franck Montmessin (5) , Oleg Korablev (3)

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics
3 IKI - Space Research Institute of the Russian Academy of Sciences
4 RSAA - Research School of Astronomy and Astrophysics [Canberra]
5 PLANETO - LATMOS

Thermal tides in the Martian atmosphere are analyzed using temperature profiles retrieved from nadir observations obtained by the TIRVIM Fourier-spectrometer, part of the Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO). The data is selected near the northern summer solstice at solar longitude (LS) 75°-105° of Martian Year (MY) 35. The observations have a full local time coverage, which enables analyses of daily temperature anomalies. The observed zonal mean temperature is lower by 4-6K at ∼100Pa, but higher towards the summer pole, compared to the LMD Mars General Circulation Model (GCM). Wave mode decomposition shows dominant diurnal tide and important semi-diurnal tide and diurnal Kelvin wave, with maximal amplitudes of 5K, 3K, and 2.5K, respectively, from tens to hundreds of Pa. The results generally agree well with the LMD Mars GCM, but with noticeable earlier phases of diurnal (∼1h) and semi-diurnal (∼3h) tides.

Keywords: TIRVIM Fourier-spectrometer; Atmospheric Chemistry Suite; ExoMars Trace Orbiter; Thermal Tides; Martian Atmosphere; Nadir Observation

Domains: Sciences of the Universe [physics]

Siteng Fan, Sandrine Guerlet, Francois, Forget, Antoine Bierjon, Ehouarn Millour, et al.. Thermal Tides in the Martian Atmosphere Near Northern Summer Solstice Observed by ACS/TIRVIM Onboard TGO. Geophysical Research Letters, 2022, 49 (7), pp.e2021GL097130. ⟨10.1029/2021GL097130⟩. ⟨insu-03619922v2⟩