EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Thermal tides in Martian atmosphere observed by EMIRS onboard the Hope spacecraft

Siteng Fan1, Francois Forget1, Michael Smith2, Sandrine Guerlet1, Khalid Badri3, Samuel Atwood4, Christopher Edwards5, Philip Christensen6, Justin Deighan4, Hessa Al Matroushi3, Antoine Bierjon1, Jiandong Liu1, and Ehouarn Millour1
Siteng Fan et al.
  • 1LMD/IPSL, Sorbonne Université, PSL Research Université, École Normale Supérieure, École Polytechnique, CNRS, Paris, France (
  • 2NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 3Mohammed Bin Rashid Space Center, Emirates Institute for Advanced Science and Technology, Al Khawaneej Area, Dubai, UAE
  • 4Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
  • 5Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ, USA
  • 6School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA

Thermal tides are planetary-scale harmonic responses driven by diurnal solar forcing and influenced by planetary topography. Excited by solar heating absorbed by the atmosphere and energy exchange with surface, thermal tides grow in Martian atmosphere. These tides usually have large amplitudes due to the low heat capacity of Martian atmosphere, and dominate its diurnal variations. In this talk, we present results of the analysis of thermal tides in Martian atmosphere using temperature profiles retrieved using infrared spectra obtained by the Emirates Mars InfraRed Spectrometer (EMIRS) instrument onboard the Emirates Mars Mission (EMM) Hope spacecraft. The first set of data obtained during the mission science phase is selected, covering a solar longitude (LS) range 60° - 80° of Martian Year (MY) 36, which is a clear season without large dust storms. The novel orbit design of the spacecraft allows a full local time coverage to be reached within 10 Martian days, approximately ~5° of LS. It enables the analysis of diurnal temperature variations without the interference of seasonal changes, which was shown to be significant in previous studies. Wave mode decomposition is also applied to these diurnal variations, and amplitudes of other tide modes are derived. The results show good agreements with predictions derived using the Laboratoire de Météorologie Dynamique (LMD) Mars Global Circulation Model (GCM), except for a noticeable phase difference of the dominant diurnal thermal tide. This work provides valuable information on understanding diurnal variations in Martian atmosphere and inspires future advances of Mars GCMs.

How to cite: Fan, S., Forget, F., Smith, M., Guerlet, S., Badri, K., Atwood, S., Edwards, C., Christensen, P., Deighan, J., Al Matroushi, H., Bierjon, A., Liu, J., and Millour, E.: Thermal tides in Martian atmosphere observed by EMIRS onboard the Hope spacecraft, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4208,, 2022.